• TABLE OF CONTENTS
HIDE
 Front Cover
 How to use this soil survey
 Table of Contents
 Index to map units
 List of Tables
 Location of Ponce Area of Southern...
 General nature of the area
 How this survey was made
 General soil map for broad land...
 Description of the soils
 Adjuntas series
 Aguilita series
 Alonso series
 Caguabo series
 Callabo series
 Cintrona series
 Constancia series
 Consumo series
 Cortada series
 Cuyon series
 Daguey series
 Ensenada series
 Fe series
 Fraternidad series
 Guanabano series
 Humatas series
 Hydraquents
 Hydraquents, saline
 Jacaguas series
 Jacana series
 Juana Diaz series
 Lares series
 Lirios series
 Llanos series
 Los Guineos series
 Machuelo series
 Maraguez series
 Maricao series
 Meros series
 Montegrande series
 Morado series
 Mucara series
 Paso Seco series
 Pellejas series
 Quebrada series
 Reilly series
 Riverwash
 San Anton series
 Serrano series
 Teresa series
 Tidal flats
 Toa series
 Tuque series
 Yauco series
 Use and management of the...
 Crops and pasture
 Capability grouping
 Estimated yields
 Woodland management and produc...
 Woodland suitability groups
 Recreation
 Engineering uses of the soils
 Soil properties significant in...
 Engineering interpretations of...
 Engineering test data
 Formation, morphology, and classification...
 Factors of soil formation
 Climate
 Plants and animals
 Parent material
 Relief
 Time
 Morphology of the soils
 Classification of the soils
 References
 Glossary
 Guide to map units
 General soil map
 Index to map sheets
 Map






Title: Soil survey of Ponce area of southern Puerto Rico.
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027417/00001
 Material Information
Title: Soil survey of Ponce area of southern Puerto Rico.
Physical Description: Book
Creator: Gierbolini, Roberto E.
Publisher: The Service
Publication Date: 1979
 Notes
Funding: U.S. Department of Agriculture Soil Surveys
 Record Information
Bibliographic ID: UF00027417
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: Government Documents Department, George A. Smathers Libraries, University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 6816216

Table of Contents
    Front Cover
        Cover
    How to use this soil survey
        Unnumbered ( 2 )
    Table of Contents
        Page i
    Index to map units
        Page ii
    List of Tables
        Page iii
    Location of Ponce Area of Southern Puerto Rico
        Page iv
    General nature of the area
        Page 1
        Climate
            Page 1
    How this survey was made
        Page 2
    General soil map for broad land use planning
        Page 3
        Soils of the humid area
            Page 3
            Caguabo-Mucara-Quebrada
                Page 3
            Humatas-Maricao-Los Guineos association
                Page 4
        Soils of the semiarid area
            Page 4
            Callabo association
                Page 4
            Aguilita-Tuque association
                Page 4
            Constancia-Jacaguas-San Anton association
                Page 5
            Fraternidad-Paso Seco association
                Page 5
    Description of the soils
        Page 6
    Adjuntas series
        Page 7
        Page 8
    Aguilita series
        Page 9
    Alonso series
        Page 10
        Page 11
    Caguabo series
        Page 12
    Callabo series
        Page 13
    Cintrona series
        Page 14
    Constancia series
        Page 15
    Consumo series
        Page 16
    Cortada series
        Page 17
    Cuyon series
        Page 17
    Daguey series
        Page 18
    Ensenada series
        Page 19
    Fe series
        Page 20
    Fraternidad series
        Page 21
    Guanabano series
        Page 22
    Humatas series
        Page 23
    Hydraquents
        Page 24
    Hydraquents, saline
        Page 24
    Jacaguas series
        Page 24
    Jacana series
        Page 25
    Juana Diaz series
        Page 26
    Lares series
        Page 27
    Lirios series
        Page 28
    Llanos series
        Page 28
        Page 29
    Los Guineos series
        Page 30
    Machuelo series
        Page 31
    Maraguez series
        Page 32
    Maricao series
        Page 33
    Meros series
        Page 34
    Montegrande series
        Page 34
    Morado series
        Page 35
    Mucara series
        Page 36
    Paso Seco series
        Page 37
    Pellejas series
        Page 38
    Quebrada series
        Page 39
    Reilly series
        Page 40
    Riverwash
        Page 41
    San Anton series
        Page 41
    Serrano series
        Page 42
    Teresa series
        Page 43
    Tidal flats
        Page 44
    Toa series
        Page 44
    Tuque series
        Page 45
    Yauco series
        Page 45
    Use and management of the soils
        Page 46
    Crops and pasture
        Page 46
    Capability grouping
        Page 47
        Page 48
    Estimated yields
        Page 49
        Page 50
        Page 51
        Page 52
    Woodland management and productivity
        Page 53
    Woodland suitability groups
        Page 53
        Page 54
        Page 55
    Recreation
        Page 56
    Engineering uses of the soils
        Page 56
        Page 57
        Page 58
    Soil properties significant in engineering
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
    Engineering interpretations of the soils
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
    Engineering test data
        Page 74
    Formation, morphology, and classification of the soils
        Page 75
    Factors of soil formation
        Page 75
    Climate
        Page 76
    Plants and animals
        Page 76
    Parent material
        Page 76
    Relief
        Page 77
    Time
        Page 77
    Morphology of the soils
        Page 77
    Classification of the soils
        Page 78
    References
        Page 78
    Glossary
        Page 78
        Page 79
        Page 80
    Guide to map units
        Page 81
    General soil map
        Page 82
    Index to map sheets
        Page 83
        Page 84
    Map
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
Full Text

P ,. *'/, 'K 172






SSOIL SURVEY OF


Ponce Area of Soulferni Puerto Rico




















..... ... .
W I







United States Department of Agriculture
Soil Conservation Service
In cooperation with the
University of Puerto Rico
College of Agricultural Sciences
College of Agricultural Sciences
















This is a publication of the National Cooperative Soil Survey, a joint effort of the United States
Department of Agriculture and agencies of the States, usually the Agricultural Experiment Stations. In
some surveys, other Federal and local agencies also contribute. The Soil Conservation Service has leader-
ship for the Federal part of the National Cooperative Soil Survey. In line with Department of Agriculture
policies, benefits of this program are available to all, regardless of race, color, national origin, sex, re-
ligion, marital status, or age.
Major fieldwork for this soil survey was performed in the period 1966-1970. Soil names and descrip-
tions were approved in 1971. Unless otherwise indicated, statements in the publication refer to conditions
in the survey area in 1970. This survey was made cooperatively by the Soil Conservation Service and the
University of Puerto Rico College of Agricultural Sciences. It is part of the technical assistance furnished
to the Sur and Caribe Soil Conservation Districts.
Soil maps in this survey may be copied without permission, but any enlargement of these maps could
cause misunderstanding of the detail of mapping and result in erroneous interpretations. Enlarged maps
do not show small areas of contrasting soils that could have been shown at a larger mapping scale.




How To Use This Soil Survey

T HIS SOIL SURVEY has information that overlay on the soil map and colored to show
can be applied in managing farms and wood- soils that have the same limitation or suitabil-
lands; in selecting sites for roads, ponds, build- ity. For example, soils that have a slight limi-
ings, and other structures; and in judging the station for a given use can be colored green,
suitability of tracts of land for farming, in- those that have a moderate limitation can be
dustry, and recreation, colored yellow, and those that have a severe
limitation can be colored red.
Locating soils Farmers and those who work with farmers
can learn about use and management of the
All the soils of the Ponce Area of Southern soils from the soil descriptions and from the
Puerto Rico are shown on the detailed map at discussion of the capability units and the wood-
the back of this publication. This map consists land groups.
of many sheets made from aerial photographs. Foresters can refer to the section "Wood-
Each sheet is numbered to correspond with a land management and productivity," where the
number on the Index to Map Sheets. soils of the county are grouped according to
On each sheet of the detailed map, soil areas their suitability for trees.
are outlined and are identified by symbols. All Community planners xand others may be in-
areas marked with the same symbol are the terested in the section "General soil map for
same kind of soil. broad land use planning" where broad patterns
of soils are described. And they can read about
Finding and using information soil properties that affect the choice of sites for
houses, industrial buildings, and recreation
The "Guide to Map Units" lists all the soils areas in the sections "Recreation" and "Engi-
of the area in alphabetic order by map symbol neering uses of the soils."
and shows the page where each soil is described. Engineers and builders can find, in the sec-
It also shows the capability classification of tion "Engineering uses of the soils," tables that
each soil and the woodland group in which the contain test data, estimates of soil properties,
soil has been placed. and information about soil features that affect
Individual colored maps showing the relative engineering practices.
suitability or degree of limitation of the soils Scientists and others can read about how the
for many specific purposes can be developed by soils formed and how they are classified in the
using the soil map and the information in the section "Formation, morphology, and classifica-
text. Translucent material can be used as an tion of the soils."


Cover: Guineagrass pasture in an area of Fraternidad-Paso
Seco soil association.













Contents

Page Page
Index to map units ----------------- ii Maraguez series -- -
Summary of tables ------- ------- iii Maricao series _--------------- 33
General nature of the area ---- -------- 1 Meros series -------------_ -- 34
Climate -------------------------------- 1 Montegrande series --------- ------ 34
How this survey was made --------------- 2 Morado series -- -- -------------- 35
General soil map for broad land use Mucara series --------------- 36
planning ------------------------------ 3 Paso Seco series ---------------------- 37
Soils of the humid area ---- --------- 3 Pellejas series ------ ---------- 38
1. Caguabo-Mucara-Quebrada Quebrada series ---------------- 39
association -------------- 3 Reilly series ------------------ 40
2. Humatas-Maricao-Los Guineos Riverwash --- ---------------- 41
association --- --------- -- 4 San Anton series -- ------------- 41
Soils of the semiarid area --------- 4 Serrano series -- --------------- 42
3. Callabo association --- ------- 4 Teresa series ________________________ 43
4. Aguilita-Tuque association ------- 4 Tidal flats __-------------------------- 44
5. Constancia-Jacaguas-San Anton Toa series __________________________ 44
association ------ -- ------- 5 Tuque series __-------------------------45
6. Fraternidad-Paso Seco association_ 5 Yauco series ----- --------------- 45
Description of the soils ------------------- 6 Use and management of the soils ---- 46
Adjuntas series ------------------------ 7 Crops and pasture -------------------- 46
Aguilita series ------- ---------- 9 Capability grouping ------------ 47
Alonso series ----- ----------- 10 Estimated yields _________________-49
Caguabo series -------- -------- 12 Woodland management and productivity_ 53
Callabo series ---------------- --- 13 Woodland suitability groups -- --- 53
Cintrona series -------- --------- 14 Recreation ----__-----------_____ 56
Constancia series -------- ------ 15 Engineering uses of the soils ------ 56
Consumo series ---------------- 16 Soil properties significant in
Cortada series ----- --------17 engineering ---- ------------ 59
Cuyon series -------------------17 Engineering interpretations of the
Daguey series --- -------------- 18 soils _____----------------- 64
Ensenada series --------------- 19 Engineering test data --------- 74
Fe series -- --- -------------- 20 Formation, morphology, and classification
Fraternidad series ---------- 21 of the soils 75
Guanabano series -22 Factors of soil formation --------- 75
Humatas series ---- ------------ 23 Climate ------- --- -----_ 76
Hydraquents --- --------------- 24 Plants and animals ----------------- 76
Hydraquents, saline ---- --------- 24 Parent material----- 76
Jacaguas series ----------- 24 Relief mateal ---------------- 77
Jacana series ------------------------25 Time -----------------------------77
T im e -------------------------------- 77
Juana Diaz series---------- 26 Morphology of the soils --------------- 77
Lares series--------------------- 27 Classification of the soils ---- ------- 78
Lirios series ------------------------- 28 References----------------------------78
Llanos series ---------- 28 References- 78
Los Guineos series ----- -------- 30 Glossary __---------------------------_ 78
Machuelo series --- ------------- 31 Guide to map units -------- Following 80

Issued November 1979







i












Index to map units

Page Page
AaF2-Adjuntas clay, 40 to 60 percent LeC-Lares clay, 5 to 12 percent slopes -- 27
slopes, eroded ------------------------ 8 LmF2-Lirios clay loam, 40 to 60 percent
AgD-Aguilita gravelly clay loam, 12 to slopes, eroded -------------- 28
20 percent slopes ----------------- 9 LnB-Llanos clay, 2 to 5 percent slopes ___ 29
AgF-Aguilita gravelly clay loam, 20 to LnC2-Llanos clay, 5 to 12 percent slopes,
60 percent slopes ------------------- 9 eroded ------ --------------- 29
AhF-Aguilita stony clay loam, 20 to 60 LuE-Los Guineos clay, 20 to 40 percent
percent slopes -- --------------- 10 slopes -------- -------- 30
AnE2-Alonso clay, 20 to 40 percent LuF-Los Guineos clay, 40 to 60 percent
slopes, eroded --------------------- 11 slopes ------------ -------- 31
AnF2-Alonso clay, 40 to 60 percent LyFX-Los Guineos-Maricao association,
slopes, eroded --------------------- 11 steep -------------------- 31
CbF2-Caguabo gravelly clay loam, 20 to LzFX-Los Guineos-Maricao-Stony rock
60 percent slopes, eroded ------------- i2 land association, steep -- ------- 31
CdF-Caguabo-Rock land complex, Ma-Machuelo clay ----------------- 32
20 to 60 percent slopes ------------- 12 MeF2-Maraguez silty clay loam, 40 to 60
CoD-Callabo silty clay loam, 12 to 20 percent slopes, eroded ------------------ 33
percent slopes --- ------------- 13 MkF2-Maricao clay, 20 to 60 percent
CoE-Callabo silty clay loam, 20 to 40 slopes, eroded --------------- 33
percent slopes ------------ ----- 13 Mr-Meros sand ------------------ 34
CoF2-Callabo silty clay loam, 40 to 60 MsC-Montegrande clay, 2 to 12 percent
percent slopes, eroded ----- --------- 14 slopes ---------------------- 35
Cr-Cintrona clay ---- ----------- 15 MtE2-Morado clay loam, 20 to 40 percent
Ct-Constancia silty clay --------------- 16 slopes, eroded --------- ------- 36
CuF2-Consumo clay, 40 to 60 percent MtF2-Morado clay loam, 40 to 60 percent
slopes, eroded --------- ---------- 16 slopes, eroded ---- -------------- 36
Cx-Cortada silty clay loam ------------ 17 MuD2-Mucara silty clay, 12 to 20 percent
CyB-Cuyon loam, 0 to 5 percent slopes -_ 18 slopes, eroded ------------------------ 37
DaD-Daguey clay, 12 to 20 percent MuE2-Mucara silty clay, 20 to 40 percent
slopes ------------- 19 slopes, eroded ------ ----- ---- 37
EnC-Ensenada gravelly clay, 2 to 12 MuF2-Mucara silty clay, 40 to 60 percent
percent slopes ----------------------- 20 slopes, eroded --------------------- 37
Fe-Fe clay -------------------------- 21 PaB-Paso Seco clay, 2 to 5 percent slopes_ 38
FtB-Fraternidad clay, 2 to 5 percent PeF2-Pellejas clay loam, 40 to 60 percent
slopes ------------------------------ 22 slopes, eroded ------------------------ 39
FtC2-Fraternidad clay, 5 to 12 percent QeD2-Quebrada silty clay loam, 12 to 20
slopes, eroded ------------------------ 22 percent slopes, eroded-----------------39
GoF-Guanabano clay, 40 to 60 percent QeE2-Quebrada silty clay loam, 20 to 40
GoFpesGuanabano clay, 40 to 60 percent percent slopes, eroded ----------------- 39
Slopes T- u a23 cly,20to40pecetQeF2-Quebrada silty clay loam, 40 to 60
HmE2-Humatas clay, 20 to 40 percent percent slopes, eroded -----------40
slopes, eroded ----------------------- 23 Re-Reilly gravelly loam ------------- 40
HmF2-Humatas clay, 40 to 60 percent Rw-Riverwash -----41
slopes, eroded ----- -------------- 24 Sa-San Anton clay loam ------------- 42
HxF-Humatas complex, 20 to 60 percent Se-Serrano sand------------------- 43
slopes ---- ---------------- 24 Te-Teresa clay---- --- ---------- 44
Hy-Hydraquents ----- ----------- 24 Tf-Tidal flats ----- ----------- 44
Hz-Hydraquents, saline --------------- 24 To-Toa silty clay loam ---- -------- 44
Jg-Jacaguas silty clay loam ----------- 25 TuF-Tuque stony clay loam, 12 to 60
JnC-Jacana clay, 5 to 12 percent slopes -_ 26 percent slopes --- ------------ 45
JzD-Juana Diaz clay loam, 12 to 20 percent YcB-Yauco silty clay loam, 2 to 5 percent
slopes ---------------------- 26 slopes ------- ------------ 46
JzE-Juana Diaz clay loam, 20 to 40 percent YcC-Yauco silty clay loam, 5 to 12 percent
slopes --------------------------- 27 slopes _-------------------- ---46


ii












Summary of tables
Page
Acreage and proportionate extent of the soils (Table 2)----------- 8
Acres. Percent.
Classification of the soils (Table 10) -------- ----------- 79
Soil name. Family. Subgroup. Order.
Engineering test data (Table 9) --------- ------------- 76
Parent material. Bureau of public roads report No. Depth.
Horizon. Moisture density-Maximum dry density, Optimum
moisture content. Percentage passing sieve number 4, 10,
40, 60, 200. Percentage smaller than 0.05 mm, 0.02 mm,
0.005 mm, 0.002 mm. Liquid limit. Plasticity index. Classi-
fication-AASHTO, Unified.
Estimated average yields per acre of principal crops under two
levels of management (Table 3) -------------------- -- 50
Sugarcane. Coffee. Plantains. Bananas. Taniers.
Pigeonpeas. Yams. Corn. Tomatoes. Peppers.
Estimated average yields per acre of principal pasture grasses
under two levels of management (Table 4) ---------- 52
Stargrass. Pangolagrass. Guineagrass. Merkergrass.
Estimated soil properties significant in engineering (Table 7) ------ 60
Depth to Bedrock, Seasonal high water table. Depth from surface.
USDA texture. Classification-Unified, AASHTO. Coarse
fragments > 3 inches. Percentage passing sieve number
4, 10, 40, 200. Liquid limit. Plasticity index.
Permeability. Available water capacity. Reaction.
Shrink-swell potential. Corrosivity to-Uncoated steel,
Concrete.
Interpretations of engineering properties of the soils (Table 8) --- 66
Septic tank absorption fields. Sewage lagoons. Shallow
excavations. Dwellings without basements. Sanitary land-
fills. Local roads and streets. Roadfill. Sand and gravel.
Topsoil. Pond reservoir areas. Dikes, levees, and embank-
ments. Drainage for crops and pasture. Irrigation.
Terraces and diversions.
Recreation (Table 6) __-_---------------- --------- 57
Camp areas. Picnic areas. Playgrounds. Paths and trails.
Temperature and precipitation (Table 1)--------------------- 2
Woodland management and productivity (Table 5) ------------- 54
Woodland group. Potential productivity. Limitations-
Erosion hazard, Equipment limitation, Seedling mortality.















iii














































SAN JUAN
AGUADILLA ARECIBO
I DESECHEO

\S 4FAJARDO .*

ECAGUAS bI CULEBRA
MAYAGUEZ


es I VIEQUBS

S* -PONCE
o A So.




I MONA State Agricultural Experiment Station


Location of Ponce Area of Southern Puerto Rico.
















Soil Survey of the Ponce Area of Southern Puerto Rico

By Roberto E. Gierbolini, Soil Conservation Service
Fieldwork by Roberto E. Gierbolini, Gilberto Acevedo, Joaquin Torres Mas, Enrique Ortiz Torres, and Luis H. Rivera, Soil Conservation
Service

United States Department of Agriculture, Soil Conservation Service, in cooperation with the University of Puerto Rico College of
Agricultural Sciences



General nature of the area acreage of these soils is irrigated. Open drains are used
on slowly permeable soils to remove excess water. Some
The Ponce Area of Southern Puerto Rico takes in an soils that have an excess of soluble salts need to be
area of 305,402 acres, or 477 square miles. Ponce, which drained and reclaimed. Some of the well drained soils
is 71 miles from San Juan, is the largest city in the on the bottom lands have been used for vegetables,
area. Other municipalities in the survey area are mainly tomatoes.
Adjuntas, Coamo, Guayanilla, Juana Diaz, Penuelas, Two agricultural experiment substations are in the
Santa Isabel, and Villalba. Coamo, Juana Diaz, Santa area, the Fortuna Substation, between Ponce and
Isabel, and Villalba are within the Caribe Soil Conser- Juana Diaz, and the Adjuntas Substation, in Barrio
vation District, and Adjuntas, Guayanilla, Penuelas, Limani of Adjuntas.
and Ponce are within the Sur Soil Conservation Dis-
trict. This survey area is bordered in the south by the Climate
Caribbean Sea.
In 1970, the population of the survey area was In most of the Ponce area the days are hot and the
309,316. About 58 percent of the population lived in nights are warm throughout the year. Winds from the
urban areas, and 42 percent lived in rural areas. Indus- sea lower the midday temperatures slightly on some
try and commerce have increased greatly in the last days. In the mountains of the interior, temperatures
10 years, mainly in and around Ponce. Petrochemical are appreciably lower than elsewhere, but freezing
industries have been established in Guayanilla and temperatures are unknown anywhere in the area. Rain-
Penuelas. Fort Allen, a U. S. Navy Base, is in this fall is heavy from about April through November. It is
survey area. lightest near the coast, where irrigation is necessary
Dairy farms are scattered throughout the survey for greatest crop yield, and heaviest in the mountains.
area. Many areas are in brush. The climate generally Table 1 gives data on temperature and precipitation
is favorable for farming, livestock, orchard fruits, and for the survey area. The data were recorded at the
woodland products. Adjuntas Substation in the mountains and at Ponce on
About 80 percent of the soils of this survey area is on the south coast.
the uplands where the slope is more than 20 percent. At Ponce, in winter the average temperature is 77
And about 60 percent of the acreage of these soils is in degrees F, and the average daily minimum tempera-
the humid area where most of the food crops in the ture is 67 degrees. The lowest temperature on record,
survey area are grown. Only about 8 percent of the which occurred on February 3, 1954, is 54 degrees. In
soils on the humid uplands is suitable for cultivation, summer the average temperature is 82 degrees, and the
These soils have such limitations as steep slopes, average daily maximum temperature is 89 degrees. The
shallowness, rapid runoff, and an erosion hazard. highest recorded temperature, which occurred on Au-
The semiarid uplands are used mainly for pasture gust 25, 1966, is 99 degrees.
because of low, poorly distributed rainfall. Long At Adjuntas, in winter the average temperature is
drought periods are common in most years from 67 degrees F, and the average daily minimum tempera-
November to May. The climate is unfavorable for ture is 55 degrees. The lowest temperature on record,
general farming, but it is favorable for raising poultry which occurred on February 7, 1975, is 44 degrees. In
and livestock. There are many dairy farms in the semi- summer the average temperature is 72 degrees, and
arid uplands and some farms that raise beef cattle. A the average daily maximum temperature is 84 degrees.
large acreage is in brush, especially in the limestone The highest recorded temperature, which occurred on
area. May 29, 1973, is 90 degrees.
The soils on the flood plains and the coastal plains in Of the total annual precipitation, 21 inches at Ponce
the semiarid area are used to grow sugarcane. Sugar- and 40 inches at Adjuntas, or 60 percent, usually falls
cane is the major crop in the survey area. A large in April through September. In 2 years out of 10, the
1
















Soil Survey of the Ponce Area of Southern Puerto Rico

By Roberto E. Gierbolini, Soil Conservation Service
Fieldwork by Roberto E. Gierbolini, Gilberto Acevedo, Joaquin Torres Mas, Enrique Ortiz Torres, and Luis H. Rivera, Soil Conservation
Service

United States Department of Agriculture, Soil Conservation Service, in cooperation with the University of Puerto Rico College of
Agricultural Sciences



General nature of the area acreage of these soils is irrigated. Open drains are used
on slowly permeable soils to remove excess water. Some
The Ponce Area of Southern Puerto Rico takes in an soils that have an excess of soluble salts need to be
area of 305,402 acres, or 477 square miles. Ponce, which drained and reclaimed. Some of the well drained soils
is 71 miles from San Juan, is the largest city in the on the bottom lands have been used for vegetables,
area. Other municipalities in the survey area are mainly tomatoes.
Adjuntas, Coamo, Guayanilla, Juana Diaz, Penuelas, Two agricultural experiment substations are in the
Santa Isabel, and Villalba. Coamo, Juana Diaz, Santa area, the Fortuna Substation, between Ponce and
Isabel, and Villalba are within the Caribe Soil Conser- Juana Diaz, and the Adjuntas Substation, in Barrio
vation District, and Adjuntas, Guayanilla, Penuelas, Limani of Adjuntas.
and Ponce are within the Sur Soil Conservation Dis-
trict. This survey area is bordered in the south by the Climate
Caribbean Sea.
In 1970, the population of the survey area was In most of the Ponce area the days are hot and the
309,316. About 58 percent of the population lived in nights are warm throughout the year. Winds from the
urban areas, and 42 percent lived in rural areas. Indus- sea lower the midday temperatures slightly on some
try and commerce have increased greatly in the last days. In the mountains of the interior, temperatures
10 years, mainly in and around Ponce. Petrochemical are appreciably lower than elsewhere, but freezing
industries have been established in Guayanilla and temperatures are unknown anywhere in the area. Rain-
Penuelas. Fort Allen, a U. S. Navy Base, is in this fall is heavy from about April through November. It is
survey area. lightest near the coast, where irrigation is necessary
Dairy farms are scattered throughout the survey for greatest crop yield, and heaviest in the mountains.
area. Many areas are in brush. The climate generally Table 1 gives data on temperature and precipitation
is favorable for farming, livestock, orchard fruits, and for the survey area. The data were recorded at the
woodland products. Adjuntas Substation in the mountains and at Ponce on
About 80 percent of the soils of this survey area is on the south coast.
the uplands where the slope is more than 20 percent. At Ponce, in winter the average temperature is 77
And about 60 percent of the acreage of these soils is in degrees F, and the average daily minimum tempera-
the humid area where most of the food crops in the ture is 67 degrees. The lowest temperature on record,
survey area are grown. Only about 8 percent of the which occurred on February 3, 1954, is 54 degrees. In
soils on the humid uplands is suitable for cultivation, summer the average temperature is 82 degrees, and the
These soils have such limitations as steep slopes, average daily maximum temperature is 89 degrees. The
shallowness, rapid runoff, and an erosion hazard. highest recorded temperature, which occurred on Au-
The semiarid uplands are used mainly for pasture gust 25, 1966, is 99 degrees.
because of low, poorly distributed rainfall. Long At Adjuntas, in winter the average temperature is
drought periods are common in most years from 67 degrees F, and the average daily minimum tempera-
November to May. The climate is unfavorable for ture is 55 degrees. The lowest temperature on record,
general farming, but it is favorable for raising poultry which occurred on February 7, 1975, is 44 degrees. In
and livestock. There are many dairy farms in the semi- summer the average temperature is 72 degrees, and
arid uplands and some farms that raise beef cattle. A the average daily maximum temperature is 84 degrees.
large acreage is in brush, especially in the limestone The highest recorded temperature, which occurred on
area. May 29, 1973, is 90 degrees.
The soils on the flood plains and the coastal plains in Of the total annual precipitation, 21 inches at Ponce
the semiarid area are used to grow sugarcane. Sugar- and 40 inches at Adjuntas, or 60 percent, usually falls
cane is the major crop in the survey area. A large in April through September. In 2 years out of 10, the
1







2 SOIL SURVEY

TABLE 1.-Temperature and precipitation

Temperature Precipitation

2 years in 2 years in 10
10 will have- Averae will have- Average
Month Average Average number of number
Average Averageofdays
daily daily Average Maximum Minimum growing Average with 0.10
maximum minimum temperature temperature degree Less More inch or
higher lower ays than- than- more
than- than-

oF F F F F Units In in In

Recorded at Adjuntas, 1970-74

January ---- 78.5 54.7 66.6 83 46 205 3.32 1.25 4.97 5
February 79.2 53.7 66.5 83 45 182 2.61 1.11 3.82 4
March ---79.9 54.3 67.1 85 47 220 4.01 1.38 6.11 7
April ___ 80.9 56.1 68.5 86 49 255 4.41 2.13 6.26 6
May --------- 81.9 59.4 70.6 87 50 329 3.88 1.63 5.70 7
June ------83.5 61.3 72.4 89 55 372 5.47 2.61 7.80 8
July ---84.0 60.4 72.2 89 55 378 6.16 3.09 8.65 9
August 83.9 61.5 72.7 88 54 394 7.61 6.62 8.56 14
September 83.8 61.0 72.4 88 56 372 12.12 7.65 16.16 14
October ---- 82.4 61.0 71.7 88 55 363 11.54 8.30 14.53 15
November --- 81.1 58.7 69.9 85 51 297 6.64 4.70 8.43 10
December --- 77.9 57.0 67.5 84 47 233 3.43 2.38 4.40 8
Year ----- 81.4 58.3 69.8 90 45 3,600 71.20 65.67 76.61 107

Recorded at Ponce, 1951-74

January -- 84.3 66.1 76.3 91 59 505 .78 .14 1.26 2
February --- 86.1 66.3 76.2 90 59 454 .72 .18 1.14 2
March ----- 86.8 66.9 76.8 91 59 521 .86 .15 1.39 2
April -- 87.3 69.2 78.2 91 63 546 1.92 .52 3.04 4
May -- --- 88.0 72.2 80.1 92 65 623 2.92 .87 4.56 4
June --------- 88.9 73.8 81.4 93 68 642 3.13 1.10 4.75 5
July --- 89.6 73.7 81.7 94 68 673 2.91 1.26 4.25 5
August 89.8 73.3 81.6 96 68 670 4.45 2.20 6.27 6
September --- 89.7 72.9 81.3 94 68 639 5.26 2.53 7.48 7
October ---89.2 72.2 80.7 94 67 642 5.63 2.03 8.51 7
November --- 88.4 69.9 79.2 92 62 576 3.18 .87 5.02 5
December --- 87.0 67.7 77.4 92 61 539 1.20 .27 1.93 3
Year ------ 87.9 70.4 79.2 96 58 7,030 32.96 23.66 41.54 52

1A growing degree day is a unit of heat available for plant growth. It can be calculated by adding the maximum and minimum
daily temperatures, dividing the sum by 2, and subtracting the temperature below which growth is minimal for the principal crops
in the area (60 F).

rainfall in April through September is less than 15 Climatic data for this survey area were specially
inches at Ponce and 33 inches at Adjuntas. The heavi- prepared for the Soil Conservation Service by the Na-
est 1-day rainfall during the period of record was 6.75 tional Climatic Center, Asheville, North Carolina.
inches at Ponce on August 28, 1970, and 11.99 inches
at Adjuntas on September 16, 1975. Thunderstorms
occur on about 40 days each year, and most occur in How this survey was made
summer.
The average relative humidity in midafternoon is Soil scientists made this survey to learn what kinds
70 percent. Humidity is higher at night, and the aver- of soil are in the survey area, where they are, and how
age at dawn is 80 percent. The percentage of possible they can be used. The soil scientists went into the area
sunshine is 60 in summer and winter. The prevailing knowing they likely would locate many soils they al-
wind is from the northeast. Average windspeed is high- ready knew something about and perhaps identify
est, 14 miles per hour, in July. some they had never seen before. They observed the
During the rainy season, an occasional tropical de- steepness, length, and shape of slopes; the size of
pression skirts or crosses the area and rainfall is ex- streams and the general pattern of drainage; the kinds
tremely heavy, causing severe flash flooding in narrow of native plants or crops; the kinds of rock; and many
valleys. Every 10 or 20 years a hurricane approaches or facts about the soils. They dug many holes to expose
crosses the area and causes wind damage and flooding, soil profiles. A profile is the sequence of natural layers,







PONCE AREA OF SOUTHERN PUERTO RICO 3

or horizons, in a soil; it extends from the surface down planning the management of a farm or field or for se-
into the parent material, which has been changed very lecting a site for a road, or building or other structure.
little by leaching or by the action of plant roots. The kinds of soil in any one association differ from
The soil scientists recorded the characteristics of the place to place in slope, depth, stoniness, drainage, or
profiles they studied, and they compared those profiles other characteristics that affect their management.
with others in areas nearby and in places more distant. The soil associations in this survey area have been
Thus, through correlation, they classified and named placed into two broad groups. These groups and the soil
the soils according to nationwide, uniform procedures, associations are described on the following pages.
After classifying and naming the soils, the soil
scientists drew the boundaries of the map units on S
aerial photographs. These photographs show wood- Soils of the humid area
lands, buildings, field borders, roads, and other details Two soil associations are in this group. They are in
that help in drawing boundaries accurately. The soil the northern half of the survey area. The soils in these
map at the back of this publication was prepared from associations formed in material that was derived from
aerial photographs. basic volcanic rock. They are mostly moderately steep
The areas shown on a soil map are called soil map to very steep and are used mainly for coffee trees, food
units. Some map units are made up of one kind of soil, crops, and native pasture. These soils receive rain
others are made up of two or more kinds of soil, and a throughout the year and have sufficient moisture for
few have little or no soil. Map units are discussed in the common crops.
the section "Description of the soils."
While a soil survey is in progress, samples of soils 1. Caguabo-Mucara-Quebrada association
are taken for laboratory measurements and for en-
gineering tests. The soils are field tested, and interpre- Moderately steep to very steep, well drained, medium
stations of their characteristics may be modified during acid to neutral, loamy and clayey soils over weathered
the course of the survey. New interpretations are made and hard rock; on side slopes and ridges on the volcanic
for local use, mainly through field observation of dif- uplands
ferent kinds of soil in different uses under different This association extends from east to west across the
levels of management. Also, data are assembled from entire width of the survey area, from the town of
other sources, such as test results, records, field experi- Coamo to Guayanilla. The landscape is mountainous
ence, and state and local specialists. For example, data and is highly dissected by intermittent streams. Nar-
on crop yields under defined practices are assembled row ridges are common.
from farm records and from field or plot experiments This association makes up about 32 percent of the
on the same kinds of soil. survey area. Caguabo soils make up about 31 percent
But only part of a soil survey is done when the soils of the association; Mucara soils, 31 percent; Quebrada
have been named, described, interpreted, and delin- soils, 17 percent; and minor soils, 21 percent.
eated on aerial photographs and when the laboratory The Caguabo soils are loamy and shallow to hard
data and other data have been assembled. The mass of rock. They are well drained and occur mainly on very
detailed information then needs to be organized so that steep side slopes. In some places, rocks cover more than
it is usable to farmers, managers of pastureland and 75 percent of the surface. The Mucara soils are clayey
woodland, engineers, planners, developers and builders, and moderately deep to volcanic rock. They are on
home buyers, and others. moderately steep to very steep hills. The Quebrada soils
are loamy and deep to volcanic rock. They are on foot
slopes, side slopes, and ridges.
The minor soils of the association are the well
General soil map for broad land use drained, loamy Morado and Maraguez soils and the
planning moderately well drained, clayey Montegrande soils.
The Morado and Maraguez soils are in the same places
The general soil map at the back of this publication as the Mucara and Quebrada soils, and the Monte-
shows, in color, soil associations that have a distinct grande soils are on narrow foot slopes. Also in this
pattern of soils and of relief and drainage. Each asso- association are well drained Toa soils and excessively
ciation is a unique natural landscape. Typically, an drained Reilly soils in some narrow strips along rivers
association consists of one or more major soils and and streams.
some minor soils. It is named for the major soils. The Generally, the soils of this association are not suit-
soils making up one association can occur in other able for cultivation because of the hazard of erosion,
associations but in a different pattern, the steep slopes, and the limited depth. They are suited
The general soil map provides a broad perspective of to use as pasture and woodland, but clearing most areas
the soils and landscape in the survey area. It provides a for pasture is difficult and expensive. The use of ma-
basis for comparing the potential of large areas for chinery is not feasible.
general kinds of land use. Areas that are, for the most A large acreage is in brush and brushy pasture.
part, suited to certain kinds of farming or to other land Many coffee farms have been abandoned, but small
uses can be identified on the map. Likewise, areas of areas of shade-grown coffee trees are still under culti-
soils having properties that are distinctly unfavorable vation, especially on the gentler slopes. In some areas
for certain land'uses can be located, the soils have been planted to grasses, such as pangola-
Because of its small scale, the map does not show the grass and stargrass, and the soils on some middle
kind of soil at a specific site. Thus, it is not suitable for slopes and foot slopes are planted periodically to food







PONCE AREA OF SOUTHERN PUERTO RICO 3

or horizons, in a soil; it extends from the surface down planning the management of a farm or field or for se-
into the parent material, which has been changed very lecting a site for a road, or building or other structure.
little by leaching or by the action of plant roots. The kinds of soil in any one association differ from
The soil scientists recorded the characteristics of the place to place in slope, depth, stoniness, drainage, or
profiles they studied, and they compared those profiles other characteristics that affect their management.
with others in areas nearby and in places more distant. The soil associations in this survey area have been
Thus, through correlation, they classified and named placed into two broad groups. These groups and the soil
the soils according to nationwide, uniform procedures, associations are described on the following pages.
After classifying and naming the soils, the soil
scientists drew the boundaries of the map units on S
aerial photographs. These photographs show wood- Soils of the humid area
lands, buildings, field borders, roads, and other details Two soil associations are in this group. They are in
that help in drawing boundaries accurately. The soil the northern half of the survey area. The soils in these
map at the back of this publication was prepared from associations formed in material that was derived from
aerial photographs. basic volcanic rock. They are mostly moderately steep
The areas shown on a soil map are called soil map to very steep and are used mainly for coffee trees, food
units. Some map units are made up of one kind of soil, crops, and native pasture. These soils receive rain
others are made up of two or more kinds of soil, and a throughout the year and have sufficient moisture for
few have little or no soil. Map units are discussed in the common crops.
the section "Description of the soils."
While a soil survey is in progress, samples of soils 1. Caguabo-Mucara-Quebrada association
are taken for laboratory measurements and for en-
gineering tests. The soils are field tested, and interpre- Moderately steep to very steep, well drained, medium
stations of their characteristics may be modified during acid to neutral, loamy and clayey soils over weathered
the course of the survey. New interpretations are made and hard rock; on side slopes and ridges on the volcanic
for local use, mainly through field observation of dif- uplands
ferent kinds of soil in different uses under different This association extends from east to west across the
levels of management. Also, data are assembled from entire width of the survey area, from the town of
other sources, such as test results, records, field experi- Coamo to Guayanilla. The landscape is mountainous
ence, and state and local specialists. For example, data and is highly dissected by intermittent streams. Nar-
on crop yields under defined practices are assembled row ridges are common.
from farm records and from field or plot experiments This association makes up about 32 percent of the
on the same kinds of soil. survey area. Caguabo soils make up about 31 percent
But only part of a soil survey is done when the soils of the association; Mucara soils, 31 percent; Quebrada
have been named, described, interpreted, and delin- soils, 17 percent; and minor soils, 21 percent.
eated on aerial photographs and when the laboratory The Caguabo soils are loamy and shallow to hard
data and other data have been assembled. The mass of rock. They are well drained and occur mainly on very
detailed information then needs to be organized so that steep side slopes. In some places, rocks cover more than
it is usable to farmers, managers of pastureland and 75 percent of the surface. The Mucara soils are clayey
woodland, engineers, planners, developers and builders, and moderately deep to volcanic rock. They are on
home buyers, and others. moderately steep to very steep hills. The Quebrada soils
are loamy and deep to volcanic rock. They are on foot
slopes, side slopes, and ridges.
The minor soils of the association are the well
General soil map for broad land use drained, loamy Morado and Maraguez soils and the
planning moderately well drained, clayey Montegrande soils.
The Morado and Maraguez soils are in the same places
The general soil map at the back of this publication as the Mucara and Quebrada soils, and the Monte-
shows, in color, soil associations that have a distinct grande soils are on narrow foot slopes. Also in this
pattern of soils and of relief and drainage. Each asso- association are well drained Toa soils and excessively
ciation is a unique natural landscape. Typically, an drained Reilly soils in some narrow strips along rivers
association consists of one or more major soils and and streams.
some minor soils. It is named for the major soils. The Generally, the soils of this association are not suit-
soils making up one association can occur in other able for cultivation because of the hazard of erosion,
associations but in a different pattern, the steep slopes, and the limited depth. They are suited
The general soil map provides a broad perspective of to use as pasture and woodland, but clearing most areas
the soils and landscape in the survey area. It provides a for pasture is difficult and expensive. The use of ma-
basis for comparing the potential of large areas for chinery is not feasible.
general kinds of land use. Areas that are, for the most A large acreage is in brush and brushy pasture.
part, suited to certain kinds of farming or to other land Many coffee farms have been abandoned, but small
uses can be identified on the map. Likewise, areas of areas of shade-grown coffee trees are still under culti-
soils having properties that are distinctly unfavorable vation, especially on the gentler slopes. In some areas
for certain land'uses can be located, the soils have been planted to grasses, such as pangola-
Because of its small scale, the map does not show the grass and stargrass, and the soils on some middle
kind of soil at a specific site. Thus, it is not suitable for slopes and foot slopes are planted periodically to food







PONCE AREA OF SOUTHERN PUERTO RICO 3

or horizons, in a soil; it extends from the surface down planning the management of a farm or field or for se-
into the parent material, which has been changed very lecting a site for a road, or building or other structure.
little by leaching or by the action of plant roots. The kinds of soil in any one association differ from
The soil scientists recorded the characteristics of the place to place in slope, depth, stoniness, drainage, or
profiles they studied, and they compared those profiles other characteristics that affect their management.
with others in areas nearby and in places more distant. The soil associations in this survey area have been
Thus, through correlation, they classified and named placed into two broad groups. These groups and the soil
the soils according to nationwide, uniform procedures, associations are described on the following pages.
After classifying and naming the soils, the soil
scientists drew the boundaries of the map units on S
aerial photographs. These photographs show wood- Soils of the humid area
lands, buildings, field borders, roads, and other details Two soil associations are in this group. They are in
that help in drawing boundaries accurately. The soil the northern half of the survey area. The soils in these
map at the back of this publication was prepared from associations formed in material that was derived from
aerial photographs. basic volcanic rock. They are mostly moderately steep
The areas shown on a soil map are called soil map to very steep and are used mainly for coffee trees, food
units. Some map units are made up of one kind of soil, crops, and native pasture. These soils receive rain
others are made up of two or more kinds of soil, and a throughout the year and have sufficient moisture for
few have little or no soil. Map units are discussed in the common crops.
the section "Description of the soils."
While a soil survey is in progress, samples of soils 1. Caguabo-Mucara-Quebrada association
are taken for laboratory measurements and for en-
gineering tests. The soils are field tested, and interpre- Moderately steep to very steep, well drained, medium
stations of their characteristics may be modified during acid to neutral, loamy and clayey soils over weathered
the course of the survey. New interpretations are made and hard rock; on side slopes and ridges on the volcanic
for local use, mainly through field observation of dif- uplands
ferent kinds of soil in different uses under different This association extends from east to west across the
levels of management. Also, data are assembled from entire width of the survey area, from the town of
other sources, such as test results, records, field experi- Coamo to Guayanilla. The landscape is mountainous
ence, and state and local specialists. For example, data and is highly dissected by intermittent streams. Nar-
on crop yields under defined practices are assembled row ridges are common.
from farm records and from field or plot experiments This association makes up about 32 percent of the
on the same kinds of soil. survey area. Caguabo soils make up about 31 percent
But only part of a soil survey is done when the soils of the association; Mucara soils, 31 percent; Quebrada
have been named, described, interpreted, and delin- soils, 17 percent; and minor soils, 21 percent.
eated on aerial photographs and when the laboratory The Caguabo soils are loamy and shallow to hard
data and other data have been assembled. The mass of rock. They are well drained and occur mainly on very
detailed information then needs to be organized so that steep side slopes. In some places, rocks cover more than
it is usable to farmers, managers of pastureland and 75 percent of the surface. The Mucara soils are clayey
woodland, engineers, planners, developers and builders, and moderately deep to volcanic rock. They are on
home buyers, and others. moderately steep to very steep hills. The Quebrada soils
are loamy and deep to volcanic rock. They are on foot
slopes, side slopes, and ridges.
The minor soils of the association are the well
General soil map for broad land use drained, loamy Morado and Maraguez soils and the
planning moderately well drained, clayey Montegrande soils.
The Morado and Maraguez soils are in the same places
The general soil map at the back of this publication as the Mucara and Quebrada soils, and the Monte-
shows, in color, soil associations that have a distinct grande soils are on narrow foot slopes. Also in this
pattern of soils and of relief and drainage. Each asso- association are well drained Toa soils and excessively
ciation is a unique natural landscape. Typically, an drained Reilly soils in some narrow strips along rivers
association consists of one or more major soils and and streams.
some minor soils. It is named for the major soils. The Generally, the soils of this association are not suit-
soils making up one association can occur in other able for cultivation because of the hazard of erosion,
associations but in a different pattern, the steep slopes, and the limited depth. They are suited
The general soil map provides a broad perspective of to use as pasture and woodland, but clearing most areas
the soils and landscape in the survey area. It provides a for pasture is difficult and expensive. The use of ma-
basis for comparing the potential of large areas for chinery is not feasible.
general kinds of land use. Areas that are, for the most A large acreage is in brush and brushy pasture.
part, suited to certain kinds of farming or to other land Many coffee farms have been abandoned, but small
uses can be identified on the map. Likewise, areas of areas of shade-grown coffee trees are still under culti-
soils having properties that are distinctly unfavorable vation, especially on the gentler slopes. In some areas
for certain land'uses can be located, the soils have been planted to grasses, such as pangola-
Because of its small scale, the map does not show the grass and stargrass, and the soils on some middle
kind of soil at a specific site. Thus, it is not suitable for slopes and foot slopes are planted periodically to food







4 SOIL SURVEY

crops. A few small dairy farms are scattered through- in these associations formed in material that weath-
out the association. ered from volcanic and limestone rocks, and others
Because of the slope, the soils of this association formed in sediment that washed from the limestone
generally have severe limitations that affect their use and volcanic uplands. Some saline soils and some soils
for buildings or other intensive development, that have expansive clays are included in these asso-
ciations. The soils in the associations are nearly level
2. Humatas-Maricao-Los Guineos association to very steep. Those on the bottom lands are used for
Steep and very steep, well drained and moderately well irrigated sugarcane, and the steeper soils are used for
drained, very strongly acid, clayey soils over thick pasture. Because of the poor distribution of rainfall,
layers of highly weathered rock; on side slopes and the soils do not receive rainfall the year round, so for
hilltops in the volcanic uplands most of the year they lack sufficient moisture for the
This association extends from east to west across common crops.
the northern part of the survey area. The largest acre- 3. Callabo association
age is in the municipality of Adjuntas. The landscape
is mountainous and is highly dissected by many inter- Moderately steep to very steep, well drained, slightly
mittent streams. Rounded hilltops are common. Some acid to neutral, loamy soils over weathered rock; on
areas are at an elevation of more than 550 meters above side slopes, foot slopes, and hilltops on the volcanic
sea level. Some areas have many rocks and boulders on uplands
the surface. This association is the largest in the semiarid part
This association makes up about 19 percent of the of the survey area. It extends from the municipality of
survey area. Humatas soils make up about 36 percent Coamo in the eastern end of the survey area to Pastillo
of the association; Maricao soils, 20 percent; Los Bajo in Ponce. The landscape is mostly mountainous,
Guineos soils, 23 percent; and minor soils, 21 percent. but some foot slopes are gently sloping to strongly
The Humatas soils are steep to very steep, well sloping.
drained, and deep to highly weathered rock. They are This association makes up about 19 percent of the
mainly,on side slopes and hilltops. Some of the Huma- survey area. Callabo soils make up about 75 percent of
tas soils have gravel throughout their profile. The the association, and minor soils make up the rest.
Maricao soils are very steep, well drained, and shallow The Callabo soils are moderately deep to semicon-
to highly weathered rock. They are mostly on side solidated rock, well drained, and loamy. They are
slopes and narrow ridges. The Los Guineos soils are mainly moderately steep to very steep.
moderately well drained and deep to weathered rock. The minor soils are the clayey Llanos soils on foot-
They are on side slopes and rounded hilltops. slopes and the Jacana soils on rounded hills; loamy
The minor soils of this association are the well Juana Diaz soils that are shallow to sandstone; and
drained, clayey Alonso, Consumo, Daguey, and Adjun- calcareous, clayey Guanabano soils. All of these soils
tas soils on side slopes; the moderately well drained, are well drained.
clayey Lares soils on terraces; and the somewhat ex- Most of the soils of this association are not suitable
cessively drained, loamy Pellejas soils and the well for cultivation because of the hazard of erosion. Long
drained, loamy Lirios soils on side slopes. Also in this drought periods are common in most years from No-
association are a few narrow strips of deep, well vember to May or June. Irrigation is possible only on
drained Toa soils and shallow, excessively drained the Jacana and Llanos soils on the lower slopes, but it
Reilly soils along the rivers and streams. is not feasible because of the scarcity of water for
A large acreage of this association is not suitable irrigation in the area. Almost all the water available
for cultivation because of steep slopes, rapid and very for irrigation is used on the bottom lands that are
-rapid runoff, and the hazard of erosion, but the less planted to sugarcane. Machinery can be used, for the
sloping soils are suitable for cultivation if they are most part, only on the lower slopes.
properly managed to control erosion. Lime and fertil- Because rainfall is low and poorly distributed, most
izer are necessary for good yields. The use of machin- of the soils are in native pasture, mainly guineagrass
ery is not feasible on most soils of the association. and Angletongrass. Some of the Callabo soils on up-
Most of the food crops in the survey area are grown lands are occasionally planted to food crops despite the
in this association. Some areas are planted to shade- hazard of erosion and difficulty of cultivation. Soils on
grown coffee trees, and some are in sun-grown coffee many of the higher ridges are in brushy forest. Many
trees. Many coffee farms have been abandoned. A large small and medium-sized dairy farms are scattered
acreage is in brush and brushy pasture. Some areas throughout the association.
belong to the government; these are in forest and Because of the slope, the soils of this association
brush. There are some small dairy farms that have generally have severe limitations that affect their use
good improved pastures, and part of the area to be for buildings and other intensive development.
mined for copper is in this association.
Because of the slope, the soils of this association 4. Aguilita-Tuque association
generally have severe limitations that affect their use Steep and very steep, well drained, moderately alka-
for buildings and other intensive development. Se Steep and very steep, well drained, moderately alka-
or buildings and other intensive development. line, loamy and clayey soils that have gravel and stones
over limestone; on foot slopes, side slopes, and hilltops
Soils of the semiarid area on the limestone uplands
Four soil associations are in this group. They are in This association is the second largest in the semiarid
the southern half of the survey area. Some of the soils part of the survey area. It is in the southwestern part







4 SOIL SURVEY

crops. A few small dairy farms are scattered through- in these associations formed in material that weath-
out the association. ered from volcanic and limestone rocks, and others
Because of the slope, the soils of this association formed in sediment that washed from the limestone
generally have severe limitations that affect their use and volcanic uplands. Some saline soils and some soils
for buildings or other intensive development, that have expansive clays are included in these asso-
ciations. The soils in the associations are nearly level
2. Humatas-Maricao-Los Guineos association to very steep. Those on the bottom lands are used for
Steep and very steep, well drained and moderately well irrigated sugarcane, and the steeper soils are used for
drained, very strongly acid, clayey soils over thick pasture. Because of the poor distribution of rainfall,
layers of highly weathered rock; on side slopes and the soils do not receive rainfall the year round, so for
hilltops in the volcanic uplands most of the year they lack sufficient moisture for the
This association extends from east to west across common crops.
the northern part of the survey area. The largest acre- 3. Callabo association
age is in the municipality of Adjuntas. The landscape
is mountainous and is highly dissected by many inter- Moderately steep to very steep, well drained, slightly
mittent streams. Rounded hilltops are common. Some acid to neutral, loamy soils over weathered rock; on
areas are at an elevation of more than 550 meters above side slopes, foot slopes, and hilltops on the volcanic
sea level. Some areas have many rocks and boulders on uplands
the surface. This association is the largest in the semiarid part
This association makes up about 19 percent of the of the survey area. It extends from the municipality of
survey area. Humatas soils make up about 36 percent Coamo in the eastern end of the survey area to Pastillo
of the association; Maricao soils, 20 percent; Los Bajo in Ponce. The landscape is mostly mountainous,
Guineos soils, 23 percent; and minor soils, 21 percent. but some foot slopes are gently sloping to strongly
The Humatas soils are steep to very steep, well sloping.
drained, and deep to highly weathered rock. They are This association makes up about 19 percent of the
mainly,on side slopes and hilltops. Some of the Huma- survey area. Callabo soils make up about 75 percent of
tas soils have gravel throughout their profile. The the association, and minor soils make up the rest.
Maricao soils are very steep, well drained, and shallow The Callabo soils are moderately deep to semicon-
to highly weathered rock. They are mostly on side solidated rock, well drained, and loamy. They are
slopes and narrow ridges. The Los Guineos soils are mainly moderately steep to very steep.
moderately well drained and deep to weathered rock. The minor soils are the clayey Llanos soils on foot-
They are on side slopes and rounded hilltops. slopes and the Jacana soils on rounded hills; loamy
The minor soils of this association are the well Juana Diaz soils that are shallow to sandstone; and
drained, clayey Alonso, Consumo, Daguey, and Adjun- calcareous, clayey Guanabano soils. All of these soils
tas soils on side slopes; the moderately well drained, are well drained.
clayey Lares soils on terraces; and the somewhat ex- Most of the soils of this association are not suitable
cessively drained, loamy Pellejas soils and the well for cultivation because of the hazard of erosion. Long
drained, loamy Lirios soils on side slopes. Also in this drought periods are common in most years from No-
association are a few narrow strips of deep, well vember to May or June. Irrigation is possible only on
drained Toa soils and shallow, excessively drained the Jacana and Llanos soils on the lower slopes, but it
Reilly soils along the rivers and streams. is not feasible because of the scarcity of water for
A large acreage of this association is not suitable irrigation in the area. Almost all the water available
for cultivation because of steep slopes, rapid and very for irrigation is used on the bottom lands that are
-rapid runoff, and the hazard of erosion, but the less planted to sugarcane. Machinery can be used, for the
sloping soils are suitable for cultivation if they are most part, only on the lower slopes.
properly managed to control erosion. Lime and fertil- Because rainfall is low and poorly distributed, most
izer are necessary for good yields. The use of machin- of the soils are in native pasture, mainly guineagrass
ery is not feasible on most soils of the association. and Angletongrass. Some of the Callabo soils on up-
Most of the food crops in the survey area are grown lands are occasionally planted to food crops despite the
in this association. Some areas are planted to shade- hazard of erosion and difficulty of cultivation. Soils on
grown coffee trees, and some are in sun-grown coffee many of the higher ridges are in brushy forest. Many
trees. Many coffee farms have been abandoned. A large small and medium-sized dairy farms are scattered
acreage is in brush and brushy pasture. Some areas throughout the association.
belong to the government; these are in forest and Because of the slope, the soils of this association
brush. There are some small dairy farms that have generally have severe limitations that affect their use
good improved pastures, and part of the area to be for buildings and other intensive development.
mined for copper is in this association.
Because of the slope, the soils of this association 4. Aguilita-Tuque association
generally have severe limitations that affect their use Steep and very steep, well drained, moderately alka-
for buildings and other intensive development. Se Steep and very steep, well drained, moderately alka-
or buildings and other intensive development. line, loamy and clayey soils that have gravel and stones
over limestone; on foot slopes, side slopes, and hilltops
Soils of the semiarid area on the limestone uplands
Four soil associations are in this group. They are in This association is the second largest in the semiarid
the southern half of the survey area. Some of the soils part of the survey area. It is in the southwestern part







4 SOIL SURVEY

crops. A few small dairy farms are scattered through- in these associations formed in material that weath-
out the association. ered from volcanic and limestone rocks, and others
Because of the slope, the soils of this association formed in sediment that washed from the limestone
generally have severe limitations that affect their use and volcanic uplands. Some saline soils and some soils
for buildings or other intensive development, that have expansive clays are included in these asso-
ciations. The soils in the associations are nearly level
2. Humatas-Maricao-Los Guineos association to very steep. Those on the bottom lands are used for
Steep and very steep, well drained and moderately well irrigated sugarcane, and the steeper soils are used for
drained, very strongly acid, clayey soils over thick pasture. Because of the poor distribution of rainfall,
layers of highly weathered rock; on side slopes and the soils do not receive rainfall the year round, so for
hilltops in the volcanic uplands most of the year they lack sufficient moisture for the
This association extends from east to west across common crops.
the northern part of the survey area. The largest acre- 3. Callabo association
age is in the municipality of Adjuntas. The landscape
is mountainous and is highly dissected by many inter- Moderately steep to very steep, well drained, slightly
mittent streams. Rounded hilltops are common. Some acid to neutral, loamy soils over weathered rock; on
areas are at an elevation of more than 550 meters above side slopes, foot slopes, and hilltops on the volcanic
sea level. Some areas have many rocks and boulders on uplands
the surface. This association is the largest in the semiarid part
This association makes up about 19 percent of the of the survey area. It extends from the municipality of
survey area. Humatas soils make up about 36 percent Coamo in the eastern end of the survey area to Pastillo
of the association; Maricao soils, 20 percent; Los Bajo in Ponce. The landscape is mostly mountainous,
Guineos soils, 23 percent; and minor soils, 21 percent. but some foot slopes are gently sloping to strongly
The Humatas soils are steep to very steep, well sloping.
drained, and deep to highly weathered rock. They are This association makes up about 19 percent of the
mainly,on side slopes and hilltops. Some of the Huma- survey area. Callabo soils make up about 75 percent of
tas soils have gravel throughout their profile. The the association, and minor soils make up the rest.
Maricao soils are very steep, well drained, and shallow The Callabo soils are moderately deep to semicon-
to highly weathered rock. They are mostly on side solidated rock, well drained, and loamy. They are
slopes and narrow ridges. The Los Guineos soils are mainly moderately steep to very steep.
moderately well drained and deep to weathered rock. The minor soils are the clayey Llanos soils on foot-
They are on side slopes and rounded hilltops. slopes and the Jacana soils on rounded hills; loamy
The minor soils of this association are the well Juana Diaz soils that are shallow to sandstone; and
drained, clayey Alonso, Consumo, Daguey, and Adjun- calcareous, clayey Guanabano soils. All of these soils
tas soils on side slopes; the moderately well drained, are well drained.
clayey Lares soils on terraces; and the somewhat ex- Most of the soils of this association are not suitable
cessively drained, loamy Pellejas soils and the well for cultivation because of the hazard of erosion. Long
drained, loamy Lirios soils on side slopes. Also in this drought periods are common in most years from No-
association are a few narrow strips of deep, well vember to May or June. Irrigation is possible only on
drained Toa soils and shallow, excessively drained the Jacana and Llanos soils on the lower slopes, but it
Reilly soils along the rivers and streams. is not feasible because of the scarcity of water for
A large acreage of this association is not suitable irrigation in the area. Almost all the water available
for cultivation because of steep slopes, rapid and very for irrigation is used on the bottom lands that are
-rapid runoff, and the hazard of erosion, but the less planted to sugarcane. Machinery can be used, for the
sloping soils are suitable for cultivation if they are most part, only on the lower slopes.
properly managed to control erosion. Lime and fertil- Because rainfall is low and poorly distributed, most
izer are necessary for good yields. The use of machin- of the soils are in native pasture, mainly guineagrass
ery is not feasible on most soils of the association. and Angletongrass. Some of the Callabo soils on up-
Most of the food crops in the survey area are grown lands are occasionally planted to food crops despite the
in this association. Some areas are planted to shade- hazard of erosion and difficulty of cultivation. Soils on
grown coffee trees, and some are in sun-grown coffee many of the higher ridges are in brushy forest. Many
trees. Many coffee farms have been abandoned. A large small and medium-sized dairy farms are scattered
acreage is in brush and brushy pasture. Some areas throughout the association.
belong to the government; these are in forest and Because of the slope, the soils of this association
brush. There are some small dairy farms that have generally have severe limitations that affect their use
good improved pastures, and part of the area to be for buildings and other intensive development.
mined for copper is in this association.
Because of the slope, the soils of this association 4. Aguilita-Tuque association
generally have severe limitations that affect their use Steep and very steep, well drained, moderately alka-
for buildings and other intensive development. Se Steep and very steep, well drained, moderately alka-
or buildings and other intensive development. line, loamy and clayey soils that have gravel and stones
over limestone; on foot slopes, side slopes, and hilltops
Soils of the semiarid area on the limestone uplands
Four soil associations are in this group. They are in This association is the second largest in the semiarid
the southern half of the survey area. Some of the soils part of the survey area. It is in the southwestern part







4 SOIL SURVEY

crops. A few small dairy farms are scattered through- in these associations formed in material that weath-
out the association. ered from volcanic and limestone rocks, and others
Because of the slope, the soils of this association formed in sediment that washed from the limestone
generally have severe limitations that affect their use and volcanic uplands. Some saline soils and some soils
for buildings or other intensive development, that have expansive clays are included in these asso-
ciations. The soils in the associations are nearly level
2. Humatas-Maricao-Los Guineos association to very steep. Those on the bottom lands are used for
Steep and very steep, well drained and moderately well irrigated sugarcane, and the steeper soils are used for
drained, very strongly acid, clayey soils over thick pasture. Because of the poor distribution of rainfall,
layers of highly weathered rock; on side slopes and the soils do not receive rainfall the year round, so for
hilltops in the volcanic uplands most of the year they lack sufficient moisture for the
This association extends from east to west across common crops.
the northern part of the survey area. The largest acre- 3. Callabo association
age is in the municipality of Adjuntas. The landscape
is mountainous and is highly dissected by many inter- Moderately steep to very steep, well drained, slightly
mittent streams. Rounded hilltops are common. Some acid to neutral, loamy soils over weathered rock; on
areas are at an elevation of more than 550 meters above side slopes, foot slopes, and hilltops on the volcanic
sea level. Some areas have many rocks and boulders on uplands
the surface. This association is the largest in the semiarid part
This association makes up about 19 percent of the of the survey area. It extends from the municipality of
survey area. Humatas soils make up about 36 percent Coamo in the eastern end of the survey area to Pastillo
of the association; Maricao soils, 20 percent; Los Bajo in Ponce. The landscape is mostly mountainous,
Guineos soils, 23 percent; and minor soils, 21 percent. but some foot slopes are gently sloping to strongly
The Humatas soils are steep to very steep, well sloping.
drained, and deep to highly weathered rock. They are This association makes up about 19 percent of the
mainly,on side slopes and hilltops. Some of the Huma- survey area. Callabo soils make up about 75 percent of
tas soils have gravel throughout their profile. The the association, and minor soils make up the rest.
Maricao soils are very steep, well drained, and shallow The Callabo soils are moderately deep to semicon-
to highly weathered rock. They are mostly on side solidated rock, well drained, and loamy. They are
slopes and narrow ridges. The Los Guineos soils are mainly moderately steep to very steep.
moderately well drained and deep to weathered rock. The minor soils are the clayey Llanos soils on foot-
They are on side slopes and rounded hilltops. slopes and the Jacana soils on rounded hills; loamy
The minor soils of this association are the well Juana Diaz soils that are shallow to sandstone; and
drained, clayey Alonso, Consumo, Daguey, and Adjun- calcareous, clayey Guanabano soils. All of these soils
tas soils on side slopes; the moderately well drained, are well drained.
clayey Lares soils on terraces; and the somewhat ex- Most of the soils of this association are not suitable
cessively drained, loamy Pellejas soils and the well for cultivation because of the hazard of erosion. Long
drained, loamy Lirios soils on side slopes. Also in this drought periods are common in most years from No-
association are a few narrow strips of deep, well vember to May or June. Irrigation is possible only on
drained Toa soils and shallow, excessively drained the Jacana and Llanos soils on the lower slopes, but it
Reilly soils along the rivers and streams. is not feasible because of the scarcity of water for
A large acreage of this association is not suitable irrigation in the area. Almost all the water available
for cultivation because of steep slopes, rapid and very for irrigation is used on the bottom lands that are
-rapid runoff, and the hazard of erosion, but the less planted to sugarcane. Machinery can be used, for the
sloping soils are suitable for cultivation if they are most part, only on the lower slopes.
properly managed to control erosion. Lime and fertil- Because rainfall is low and poorly distributed, most
izer are necessary for good yields. The use of machin- of the soils are in native pasture, mainly guineagrass
ery is not feasible on most soils of the association. and Angletongrass. Some of the Callabo soils on up-
Most of the food crops in the survey area are grown lands are occasionally planted to food crops despite the
in this association. Some areas are planted to shade- hazard of erosion and difficulty of cultivation. Soils on
grown coffee trees, and some are in sun-grown coffee many of the higher ridges are in brushy forest. Many
trees. Many coffee farms have been abandoned. A large small and medium-sized dairy farms are scattered
acreage is in brush and brushy pasture. Some areas throughout the association.
belong to the government; these are in forest and Because of the slope, the soils of this association
brush. There are some small dairy farms that have generally have severe limitations that affect their use
good improved pastures, and part of the area to be for buildings and other intensive development.
mined for copper is in this association.
Because of the slope, the soils of this association 4. Aguilita-Tuque association
generally have severe limitations that affect their use Steep and very steep, well drained, moderately alka-
for buildings and other intensive development. Se Steep and very steep, well drained, moderately alka-
or buildings and other intensive development. line, loamy and clayey soils that have gravel and stones
over limestone; on foot slopes, side slopes, and hilltops
Soils of the semiarid area on the limestone uplands
Four soil associations are in this group. They are in This association is the second largest in the semiarid
the southern half of the survey area. Some of the soils part of the survey area. It is in the southwestern part








PONCE AREA OF SOUTHERN PUERTO RICO 5

of the survey area and extends from Ponce to Guay- sand and gravel at a depth of 12 to 20 inches. These
anilla. A large part of this association in the area of soils are closer to the rivers and are subject to more
Ponce and Penuelas is bordered on the south by the frequent flooding than the other soils of the associa-
sea. The landscape is mountainous with rounded hill- tion. The San Anton soils are deep, well drained, and
tops and gravelly foot slopes. Some foot slopes are free loamy. They are easily worked and are the best soils
of gravel and stones. for farming in the association.
This association makes up about 13 percent of the The minor soils of the association are deep, well
survey area. Aguilita soils make up about 69 percent drained Cortada soils that are easily worked; poorly
of the association; Tuque soils, about 18 percent; and drained, clayey Machuelo and Cintrona soils; saline
minor soils, 13 percent. Serrano and Teresa soils; Meros sands; and loamy,
The Aguilita soils are loamy and shallow to soft shallow Cuyon soils that are closer to the riverbanks.
gravelly limestone. They are mainly steep to very Some areas of Hydraquents; Hydraquents, saline; and
steep and occupy side slopes and hilltops. Some of these Tidal flats are also in the association. These areas have
soils have stones on the surface. The Tuque soils are no value for farming.
loamy, are shallow to a caliche horizon, and are under- The soils of this association are the best soils for
lain by soft gravelly limestone. They are mostly steep farming in the Ponce area. Long drought periods are
to very steep and on side slopes; on some hilltops they common in most years, and because rainfall is low and
are less steep. Aguilita soils and Tuque soils are well poorly distributed, the soils need to be irrigated. Many
drained. lakes and ponds provide water for irrigation. In some
The minor soils of the association are well drained, years the entire area is flooded as a result of heavy
gravelly, clayey Ensenada soils on terraces and well rains during the period from August to October. The
drained, loamy Yauco soils on foot slopes, slowly permeable soils retain water on the surface for
The soils of this association generally are not suit- a few days after they are flooded, and most of the
able for cultivation because of slope, runoff, the large slowly permeable soils are artificially drained to re-
amount of gravel and stones, and shallowness to lime- move excess water. Saline soils in the association are
stone. Rainfall is low and poorly distributed through- difficult and expensive to reclaim. Farm machinery can
out the year, and long drought periods are common in be used in most areas of the association.
most years. Almost all the acreage of the Tuque and Sugarcane is the major cash crop, and almost all the
Aguilita soils west of Ponce are in brush. Clearing sugarcane grown in the survey area is grown in this
this area for pasture is difficult and expensive. Much of association. Some areas are planted to vegetables.
the acreage of Aguilita gravelly clay loam is in native The soils of this association generally have severe
pasture of low carrying capacity. Some patches of limitations for use as housing sites because of the
guineagrass and Angletongrass are scattered through- hazard of flooding, but in areas close to cities, towns,
out this area. Some Ensenada and Yauco soils on foot and villages, these limitations are being overcome so
slopes are planted to irrigated sugarcane. The use of that the soils can be used for housing and industry.
machinery is feasible only on these lower slopes. Some of the soils close to the rivers have good potential
Because of slope and the large amount of stones, the as a source of gravel.
soils of this association have severe limitations for use
as housing sites and for intensive industrial develop- 6. Fraternidad-Paso Seco association
ment. Soil material from this association is used as fill Gently sloping to strongly sloping, moderately well
for highway and housing construction. Gently sloping to strongly sloping, moderately well
for highway and housing construction, drained, neutral to moderately alkaline, clayey soils
5. Constancia-Jacaguas-San Anton association that are deep or moderately deep to sand and gravel;
on terraces, alluvial fans, and foot slopes on the coastal
Nearly level, somewhat poorly drained and well plain
drained, neutral to moderately alkaline, loamy and association is the least extensive in the survey
clayey soils that are deep or shallow to sand and This association is the least extensive in the survey
area. It is on the coastal plain slightly above the river
gravel; on the river flood plains flood plains. The largest part extends from Coamo
This association is in the southernmost part of the Lake, in the eastern part of the survey area, to Coto
Ponce Area. It extends from east to west across the Laurel, near the city of Ponce. A small area is near the
survey area and is bordered on the south by the sea. town of Cayures, northeast of Santa Isabel. Some of
It is made up of bottom lands along the major rivers, the soils of this association are saline.
Many rivers and streams in the association overflow This association makes up about 5 percent of the
in some years. Loamy soils are dominant in the asso- survey area. Fraternidad soils make up about 75 per-
ciation, but clayey and sandy soils are included. Some cent of the association; Paso Seco soils, 18 percent;
of the soils are saline, and minor soils, the remaining 7 percent.
This association makes up about 12 percent of the Fraternidad soils are gently sloping to strongly
survey area. Constancia soils make up about 20 percent sloping and are mainly on terraces. The Paso Seco
of the association; Jacaguas soils, 16 percent; San soils are underlain by sand and gravel at a depth of 2
Anton soils, 14 percent; and minor soils, the remain- to 3 feet. They are on terraces and alluvial fans.
ing 50 percent. The minor soils of the association are the somewhat
Constancia soils are somewhat poorly drained and poorly drained Fe soils, which are saline and clayey.
clayey. The water table is at a depth of 17 to 48 inches The soils of this association are generally suitable
after the soils have been drained. The Jacaguas soils for intensive cultivation if they are properly managed,
are well drained and loamy. They are underlain by drained, and irrigated. They are best suited to irri-








PONCE AREA OF SOUTHERN PUERTO RICO 5

of the survey area and extends from Ponce to Guay- sand and gravel at a depth of 12 to 20 inches. These
anilla. A large part of this association in the area of soils are closer to the rivers and are subject to more
Ponce and Penuelas is bordered on the south by the frequent flooding than the other soils of the associa-
sea. The landscape is mountainous with rounded hill- tion. The San Anton soils are deep, well drained, and
tops and gravelly foot slopes. Some foot slopes are free loamy. They are easily worked and are the best soils
of gravel and stones. for farming in the association.
This association makes up about 13 percent of the The minor soils of the association are deep, well
survey area. Aguilita soils make up about 69 percent drained Cortada soils that are easily worked; poorly
of the association; Tuque soils, about 18 percent; and drained, clayey Machuelo and Cintrona soils; saline
minor soils, 13 percent. Serrano and Teresa soils; Meros sands; and loamy,
The Aguilita soils are loamy and shallow to soft shallow Cuyon soils that are closer to the riverbanks.
gravelly limestone. They are mainly steep to very Some areas of Hydraquents; Hydraquents, saline; and
steep and occupy side slopes and hilltops. Some of these Tidal flats are also in the association. These areas have
soils have stones on the surface. The Tuque soils are no value for farming.
loamy, are shallow to a caliche horizon, and are under- The soils of this association are the best soils for
lain by soft gravelly limestone. They are mostly steep farming in the Ponce area. Long drought periods are
to very steep and on side slopes; on some hilltops they common in most years, and because rainfall is low and
are less steep. Aguilita soils and Tuque soils are well poorly distributed, the soils need to be irrigated. Many
drained. lakes and ponds provide water for irrigation. In some
The minor soils of the association are well drained, years the entire area is flooded as a result of heavy
gravelly, clayey Ensenada soils on terraces and well rains during the period from August to October. The
drained, loamy Yauco soils on foot slopes, slowly permeable soils retain water on the surface for
The soils of this association generally are not suit- a few days after they are flooded, and most of the
able for cultivation because of slope, runoff, the large slowly permeable soils are artificially drained to re-
amount of gravel and stones, and shallowness to lime- move excess water. Saline soils in the association are
stone. Rainfall is low and poorly distributed through- difficult and expensive to reclaim. Farm machinery can
out the year, and long drought periods are common in be used in most areas of the association.
most years. Almost all the acreage of the Tuque and Sugarcane is the major cash crop, and almost all the
Aguilita soils west of Ponce are in brush. Clearing sugarcane grown in the survey area is grown in this
this area for pasture is difficult and expensive. Much of association. Some areas are planted to vegetables.
the acreage of Aguilita gravelly clay loam is in native The soils of this association generally have severe
pasture of low carrying capacity. Some patches of limitations for use as housing sites because of the
guineagrass and Angletongrass are scattered through- hazard of flooding, but in areas close to cities, towns,
out this area. Some Ensenada and Yauco soils on foot and villages, these limitations are being overcome so
slopes are planted to irrigated sugarcane. The use of that the soils can be used for housing and industry.
machinery is feasible only on these lower slopes. Some of the soils close to the rivers have good potential
Because of slope and the large amount of stones, the as a source of gravel.
soils of this association have severe limitations for use
as housing sites and for intensive industrial develop- 6. Fraternidad-Paso Seco association
ment. Soil material from this association is used as fill Gently sloping to strongly sloping, moderately well
for highway and housing construction. Gently sloping to strongly sloping, moderately well
for highway and housing construction, drained, neutral to moderately alkaline, clayey soils
5. Constancia-Jacaguas-San Anton association that are deep or moderately deep to sand and gravel;
on terraces, alluvial fans, and foot slopes on the coastal
Nearly level, somewhat poorly drained and well plain
drained, neutral to moderately alkaline, loamy and association is the least extensive in the survey
clayey soils that are deep or shallow to sand and This association is the least extensive in the survey
area. It is on the coastal plain slightly above the river
gravel; on the river flood plains flood plains. The largest part extends from Coamo
This association is in the southernmost part of the Lake, in the eastern part of the survey area, to Coto
Ponce Area. It extends from east to west across the Laurel, near the city of Ponce. A small area is near the
survey area and is bordered on the south by the sea. town of Cayures, northeast of Santa Isabel. Some of
It is made up of bottom lands along the major rivers, the soils of this association are saline.
Many rivers and streams in the association overflow This association makes up about 5 percent of the
in some years. Loamy soils are dominant in the asso- survey area. Fraternidad soils make up about 75 per-
ciation, but clayey and sandy soils are included. Some cent of the association; Paso Seco soils, 18 percent;
of the soils are saline, and minor soils, the remaining 7 percent.
This association makes up about 12 percent of the Fraternidad soils are gently sloping to strongly
survey area. Constancia soils make up about 20 percent sloping and are mainly on terraces. The Paso Seco
of the association; Jacaguas soils, 16 percent; San soils are underlain by sand and gravel at a depth of 2
Anton soils, 14 percent; and minor soils, the remain- to 3 feet. They are on terraces and alluvial fans.
ing 50 percent. The minor soils of the association are the somewhat
Constancia soils are somewhat poorly drained and poorly drained Fe soils, which are saline and clayey.
clayey. The water table is at a depth of 17 to 48 inches The soils of this association are generally suitable
after the soils have been drained. The Jacaguas soils for intensive cultivation if they are properly managed,
are well drained and loamy. They are underlain by drained, and irrigated. They are best suited to irri-








6 SOIL SURVEY

gated sugarcane, and most of the acreage has been in in the Ponce Area of Southern Puerto Rico. Each soil
sugarcane that is furrow irrigated. There are many series is described in detail, and then each map unit in
small ponds to store water for irrigation in this asso- that series is briefly described. Unless mentioned
ciation. The use of machinery is feasible, but care otherwise, it is to be assumed that what is stated about
should be taken to avoid moving the earth when the the soil series holds true for the map units in that
soils are wet. series. Thus, to get full information about any one map
The saline soils of this association are not ex- unit, it is necessary to read both the description of the
tensive and are barren or are in salt-tolerant weeds. map unit and the description of the soil series to which
No attempts have been made to reclaim areas of these it belongs.
saline soils. Some areas where irrigation is not feasible An important part of the description of each soil
are in pasture (fig. 1). There are some small dairy series is the soil profile, that is, the sequence of layers
farms in this association. from the surface downward to rock or other underly-
Generally, the soils have some limitations that af- ing material. Each series contains two descriptions of
feet housing and industrial development because of the this profile. The first is brief and in terms familiar to
shrink-swell behavior of the expansive clays, the layman. The second is much more detailed and is
for those who need to make thorough and precise
studies of soils. Color terms are for moist soil unless
Description of the soils otherwise stated. The profile described in the series is
representative of map units in that series. If the pro-
This section describes the soil series and map units file of a given map unit is different from the one






































Figure 1.-Some areas of the Fraternidad-Paso Seco association, where irrigation is not feasible, are in pasture.







PONCE AREA OF SOUTHERN PUERTO RICO 7

described for the series, the differences are stated in no soil material and support little or no vegetation.
the description of the map unit, or they are differences Such places are called miscellaneous areas; they are
that are apparent in the name of the map unit. delineated on the soil map and given descriptive
Preceding the name of each map unit is the symbol names. Riverwash is an example. Some of these areas
that identifies the soil on the detailed soil maps. Each are too small to be delineated and are identified by a
soil description includes general facts about the soil. special symbol on the soil map.
In each description, the principal hazards and limita- The acreage and proportionate extent of each map
tions are indicated, and the management concerns and unit are given in table 2, and additional information
practices needed are discussed. Listed at the end of on properties and limitations for many soil uses is
each description of a map unit is the capability unit given for each kind of soil in other tables. (See "Sum-
and woodland group in which the map unit has been mary of tables.") Many of the terms used in describing
placed. soils are defined in the Glossary, and detailed informa-
The map units on the detailed soil maps represent an tion about the terminology and methods of soil
area on the landscape made up mostly of the soil or mapping can be obtained from the Soil Survey
soils for which the unit is named. Most of the delin- Manual (3).1
eations shown on the detailed soil map are phases of
soil series. Ad s
Soils that have profiles that are almost alike make Ajuntas series
up a soil series. Except for allowable differences in tex-
ture of the surface layer or of the underlying substra- The Adjuntas series consists of well drained, very
tum, all the soils of a series have major horizons that steep soils. Slope ranges from 40 to 60 percent. These
are similar in composition, thickness, and arrangement soils formed in fine textured residuum of weathered
in the profile. volcanic rock that is high in quartz. These soils occur
Not all map units are phases of a soil series. Hydra- on short side slopes and narrow ridgetops of the
quents, for example, are a broader group of soils and do strongly dissected humid uplands. The annual rainfall
not belong to -a series. They are, however, listed in ranges from 80 to 90 inches. The annual temperature
alphabetic order along with the soil series, ranges from 750 to 770F.
Soils of one series can differ in texture of the surface In a representative profile, the surface layer is dark
layer or in the underlying substratum and in slope, brown, clay about 5 inches thick. The subsoil is about
erosion, stoniness, salinity, wetness, or other charac- 19 inches thick. In the upper 5 inches it is dark brown
teristics that affect their use. On the basis of such and strong brown, firm clay; in the 7 inches below that
differences, a soil series is divided into phases. The it is strong brown, firm clay; and in the lowermost
name of a soil phase commonly indicates a feature that 7 inches it is yellow, white, and brownish yellow, firm
affects use or management. For example, Juana Diaz clay with red mottles. The substratum, to a depth of
clay loam, 12 to 20 percent slopes, is one of several 48 inches, is strongly and partly weathered volcanic
phases within the Juana Diaz series, rock. Semiconsolidated rock is at a depth of more than
Some map units are made up of two or more domi- 4 feet.
nant kinds of soil. Such map units are called soil com- These soils are moderately permeable. They have
plexes and soil associations. moderate available water capacity and low natural
A soil complex consists of areas of two or more soils fertility. They are somewhat difficult to work. Runoff
that are so intricately mixed or so small in size that is very rapid. These soils are highly susceptible to ero-
they cannot be shown separately on the soil map. Each sion.
area includes some of each of the two or more domi- The Adjuntas soils have been in native pasture and
nant soils, and the pattern and proportion are some- brush for many years. A few acres are in coffee. The
what similar in all areas. Caguabo-Rock land complex soils are suited to native pasture, pangolagrass, and
is an example. woodland.
A soil association is made up of soils that are geo- Representative profile of Adjuntas clay, 40 to 60
graphically associated and are shown as one unit on percent slopes, eroded, 320 meters east of school at
the map because it is not practical to separate them. dead end of Highway 602:
A soil association has considerable regularity in geo- Ap-0 to 5 inches; dark brown (10YR 3/3) clay;
graphic pattern and in the kinds of soil that are a part moderate fine and medium granular
of it. The extent of the soils can differ appreciably structure; firm, slightly sticky and plas-
from one delineation to another; nevertheless, interpre- tic; many fine roots; few fine and me-
tations can be made for use and management of the dium volcanic rock fragments; few fine
soils. Los Guineos-Maricao association is an example. quartz grains; many fine pores; very
Most map units include small, scattered areas of strongly acid; clear smooth boundary.
soils other than those that appear in the name of the B1-5 to 10 inches; dark brown (7.5YR 4/4) and
map unit. Some of these soils have properties that dif- strong brown (7.5YR 5/6) clay; weak
fer substantially from those of the dominant soil or fine subangular blocky structure; firm,
soils and thus could significantly affect use and man- slightly sticky and plastic; common fine
agement of the map unit. These soils are described in roots; few patchy clay films; few fine
the description of each map unit. Some of the more and medium volcanic rock fragments;
unusual or strongly contrasting soils that are included few fine quartz grains; many fine pores;
are identified by a special symbol on the soil map.
Most mapped areas include places that have little or 1Italic numbers in parentheses refer to References, p. 78.







8 SOIL SURVEY

TABLE 2.-Acreage and proportionate extent of the soils

Soil Acres1 Percent Soil Acres Percent

Adjuntas clay, 40 to 60 percent slopes, eroded- 360 0.1 Llanos clay, 5 to 12 percent slopes, eroded -- 6,000 2.0
Aguilita gravelly clay loam, 12 to 20 percent Los Guineos clay, 20 to 40 percent slopes 2,560 .8
slope ---- ---------------------- 920 .3 Los Guineos clay, 40 to 60 percent slopes 6,470 2.1
Aguilita gravelly clay loam, 20 to 60 percent Los Giineos-Maricao association, steep ___-- 7,040 2.3
slopes -------------------------------- 14,680 4.8 Los Guineos-Maricao-Stony rock land associa-
Aguilita stony clay loam, 20 to 60 percent tion, steep --------------------------- 2,000 .7
slopes ------------------------------- 11,710 3.8 Machuelo clay------------------------ 1,770 .6
Alonso clay, 20 to 40 percent slopes, eroded -- 1,200 .4 Maraguez silty clay loam, 40 to 60 percent
Alonso clay, 40 to 60 percent slopes, eroded 1,980 .6 slopes, eroded ------------------------- 6,460 2.1
Caguabo gravelly clay loam, 20 to 60 percent Maricao clay, 20 to 60 percent slopes, eroded-- 8,840 2.9
slopes, eroded ------------------------- 23,900 7.8 Meros sand ---------------------------- 1,240 .4
Caguabo-Rock land complex, 20 to 60 percent Montegrande clay, 2 to 12 percent slopes ---- 2,990 1.0
slopes -------------------------------- 6,600 2.2 Morado clay loam, 20 to 40 percent slopes,
Callabo silty clay loam, 12 to 20 percent slopes- 5,100 1.7 eroded -------------------------------- 870 .3
Callabo silty clay loam, 20 to 40 percent slopes- 9,260 3.0 Morado clay loam, 40 to 60 percent slopes,
Callabo silty clay loam, 40 to 60 percent slopes eroded -------------------------------- 9,760 3.2
eroded ----------------------------- 29,702 9.7 Mucara silty clay, 12 to 20 percent slopes,
Cintrona clay ..---------------------------- 1,390 .5 eroded -------------------------------- 530 .2
Constancia silty clay ------------------- 7,190 2.4 Mucara silty clay, 20 to 40 percent slopes,
Consume clay, 40 to 60 percent slopes, eroded- 2,120 .7 eroded -------------------------------- 1,770 .6
Cortada silty clay loam ------------------ 3,760 1.2 Mucara silty clay, 40 to 60 percent slopes,
Cuyon loam, 0 to 5 percent slopes ---------- 1,910 .6 eroded -------------------------------- 27,950 9.2
Daguey clay, 12 to 20 percent slopes -------- 1,780 .6 Paso Seco clay, 2 to 5 percent slopes -------- 2,820 .9
Ensenada gravelly clay, 2 to 12 percent slopes- 390 .1 Pellejas clay loam, 40 to 60 percent slopes,
Fe clay -------------------------- 870 .3 eroded ------------------------------- 730 .2
Fraternidad clay, 2 to 5 percent slopes ---- 9,460 3.1 Quebrada silty clay loam, 12 to 20 percent
Fraternidad clay, 5 to 12 percent slopes, slopes, eroded ------------------------- 1,210 .4
eroded -------------------------------- 2,890 .9 Quebrada silty clay loam, 20 to 40 percent
Guanabano clay. 40 to 60 percent slopes ---- 920 .3 slopes, eroded -------------------------- 1,910 .6
Humatas clay, 20 to 40 percent slopes, eroded- 3,590 1.2 Quebrada silty clay loam, 40 to 60 percent
Humatas clay. 4- to 60 percent slopes, eroded- 15,760 5.2 slopes, eroded ------------------------- 13,800 4.5
Humatas compllex, 20 to 60 percent slopes --- 1,060 .3 Reilly gravelly loam --------------------- 1,000 .3
Hydraquents ------- ------------ 170 .1 Riverwash ------------------------------- 200 .1
Hydraquents, saline ---------------------- 2,240 .7 San Anton clay loam -------------------- 5,850 1.9
Jacaguas silty clay loam ------------------ 6,100 2.0 Serrano sand ---------------------------- 950
Jacana clay,, 5 to 12 percent slopes -------- 2,020 .7 Teresa clay ----------------------------- 3,740 1.2
Juana Diaz clay loam, 12 to 20 percent slopes_ 440 .1 Tidal flats -------------------------- 330 .1
Juana Diaz clay loam, 20 to 40 percent slopes- 280 .1 Toa silty clay loam ----------------------- 1,160 .4
Lares clay, 5 to 12 percent slopes ---------- 390 .1 Tuque stony clay loam, 12 to 60 percent slopes- 7,750 2.5
Lirios clay loam, 40 to 60 percent slopes, Yauco silty clay loam, 2 to 5 percent slopes 1,100 .4
eroded ---. ----- -- ------------- 590 .2 Yauco silty clay loam, 5 to 12 percent slopes -- 2,300 .8
Llanos clay, 2 to 5 percent slopes --------- 3,570 1.2 Total ------------------------------ 305,402 100.0

Map unit acreages have been adjusted to the official survey a rea acreage of 305,402.


very strongly acid; clear smooth bound- ranges from dark brown (10YR 3/3) to brown (10YR
ary. 4/3). Depth to semiconsolidated rock ranges from 48
B2-10 to 17 inches; strong brown (7.5YR 5/6) to 72 inches.
clay; weak fine and medium subangular Adjuntas soils occur on the same landscape as the
blocky structure; firm, slightly sticky Consumo, Daguey, Humatas, and Maraguez soils. Ad-
and plastic; few fine roots; common juntas soils are less red and more shallow to volcanic
patchy clay films; few fine volcanic rock rock than Consumo, Daguey, and Humatas soils. Ad-
fragments; few fine quartz grains; many juntas soils are more acid and have finer texture than
fine pores; very strongly acid; clear Maraguez soils.
wavy boundary. AaF2-Adjuntas clay, 40 to 60 percent slopes, eroded.
B3-17 to 24 inches; yellow (10YR 7/6), white This is a very steep soil on short side slopes and nar-
(10YR 8/2), and brownish yellow row ridges of the strongly dissected, humid uplands.
(10YR 6/8) clay; common fine promi- It generally is in areas of more than 100 acres.
nent red (2.5YR 4/6) mottles; weak Included with this soil in mapping are a few small
medium subangular blocky structure; areas of Consumo clay and Maraguez silty clay loam.
friable, slightly sticky and plastic; few Also included are some areas, on narrow foot slopes,
fine roots; many fine pores; many quartz where the slope is less than 40 percent.
grains; very strongly acid; clear wavy Runoff is very rapid, and erosion is a hazard. Deep
boundary, gullies are common in drainageways. Slippage is a
C-24 to 48 inches; strongly and partly weath- hazard in roadbanks, ditches, and drainageways.
ered volcanic rock. Clearing of brushy areas is costly. Liming and fertil-
The solum is 20 to 32 inches thick. The Ap horizon izing are difficult and costly. Because of the steep







PONCE AREA OF SOUTHERN PUERTO RICO 9

slopes, diversion ditches are difficult to lay out, con- to 60 percent of the surface. The Al horizon is 7 to 12
struct, and maintain. This soil has a deep root zone. inches thick. It has value and chroma of 3 or less. The
Because of the steep slopes, rapid runoff, and ero- AC horizon has value and chroma of 3 or higher.
sion hazard, this soil has severe limitations for cultiva- Depth to the soft limestone ranges from 11 to 18 inches.
tion. It should be maintained under permanent The amount of fine and coarse hard limestone frag-
vegetation. ments in the profile ranges from 40 to more than 50
This soil has been mostly in brush and native pas- percent.
tures of low carrying capacity. A few acres are in Aguilita soils are on the same landscape as the Yauco
shade-grown coffee. and Tuque soils. Aguilita soils are shallower to the soft
Capability unit VIIe-1; woodland suitability group limestone than the Yauco soils, and they have gravel
3rl. throughout the profile. Unlike the Tuque soils, Aguilita
soils do not have an indurated caliche layer.
AgD-Aguilita gravelly clay loam, 12 to 20 percent
Aguilita series slopes. This moderately steep soil is on side slopes, foot
slopes, and rounded hilltops of the semiarid uplands.
The Aguilita series consists of well drained, cal- It generally is in areas of about 5 to 20 acres. This
careous, moderately steep to very steep soils on foot soil is similar to the one described as typical of the
slopes, side slopes, and rounded hilltops in the semi- series, except that the surface layer is slightly thicker.
arid area. Slope ranges from 12 to 60 percent. These Included with this soil in mapping are small areas
soils formed in moderately fine textured residuum of that have 10 to 20 percent cobbles on the surface. Also
soft limestone. The annual rainfall ranges from 25 to included are some areas of soils that are not gravelly
45 inches. The annual temperature ranges from 780 in the surface layer.
to 800 F. Runoff is medium on this soil, and erosion is a haz-
In a representative profile, the surface layer is very ard. This soil is fertile, but some measures for con-
dark grayish brown gravelly clay loam about 8 inches trolling erosion are needed if the soil is to be used for
thick. The subsoil, extending to a depth of 13 inches, is cultivated crops. Because rainfall is low and unevenly
dark brown and pale yellow, friable gravelly clay loam. distributed throughout the year, there are few adapted
The substratum, to a depth of 60 inches, is pale yellow, species of grasses on this soil. Long drought periods
white, and gray, friable, soft gravelly limestone; the are common. Irrigation is not feasible. The soil has a
substratum consists of more than 50 percent hard lime- limited root zone because of the high content of cal-
stone fragments. cium carbonate.
Aguilita soils are moderately permeable. They have This soil generally is not suitable for cultivation be-
low available water capacity and high natural fertility, cause of slope, medium runoff, and the erosion hazard.
Because of the high content of calcium carbonate, the It should be maintained in permanent vegetation.
depth of the root zone is restricted. The organic matter Angletongrass and guineagrass are the best adapted
content generally is high in the surface layer. grasses on this soil.
Aguilita soils have been in native pasture and brush This soil has been used mainly for grazing. Some
for many years. They are well suited to native pasture, areas are in brush. A good stocking rate is necessary
especially Angletongrass and guineagrass (fig. 2). to avoid overgrazing and to maintain a good stand of
They are used mainly as a source of roadfill because of pasture.
the physical properties of the limestone and because Capability unit VIe-2; woodland suitability group
they are in areas close to the cities. 2x1.
Representative profile of Aguilita gravelly clay loam, AgF-Aguilita gravelly clay loam, 20 to 60 percent
20 to 60 percent slopes, in an area 150 meters north slopes. This steep to very steep soil is on side slopes and
of kilometer marker 3.7 on Highway 149: ridges in the semiarid area. It generally is in areas
A1-0 to 8 inches; very dark grayish brown of more than 100 acres. It is the soil described as
(10YR 3/2) gravelly clay loam; moder- representative of the series. Cobbles and stones are
ate fine granular structure; firm, slightly scattered on 5 to 15 percent of the surface.
sticky and slightly plastic; many fine Included with this soil in mapping are small areas of
roots; 40 percent fine and coarse lime- soils that do not have gravel in the surface layer and
stone fragments; moderately alkaline; many small severely eroded spots where soft limestone
abrupt smooth boundary. is in the surface layer.
AC-8 to 13 inches; 40 percent dark brown Runoff is rapid to very rapid, and erosion is a haz-
(10YR 3/3) and 60 percent pale yellow ard. This soil is not suitable for cultivation. Because
(2.5Y 7/4) gravelly clay loam; weak fine rainfall is low and is poorly distributed during the
granular structure; friable, slightly year, the use of this soil is restricted to range, but few
sticky and slightly plastic; many fine adapted species of grasses are grown. Long periods of
roots; 40 percent fine and coarse lime- drought are common in most years. Irrigation is not
stone fragments; moderately alkaline; feasible. Seeding and fertilizing are difficult and costly.
clear smooth boundary. This soil has been mainly in pasture and brush.
C-13 to 60 inches; pale yellow, white, and gray Clearing the brush for pasture is costly. The limita-
friable soft gravelly limestone; more tions for cultivation are severe because of slope, shal-
than 50 percent, by volume, hard lime- low depth to soft limestone, and the erosion hazard.
stone gravel. Permanent vegetation should be maintained. A con-
In some areas, stones and rocks are scattered on 30 trolled stocking rate is necessary to avoid overgrazing.








10 SOIL SURVEY








































Figure 2.-The Aguilita soils are shallow to soft limestone, but they are well suited to guineagrass pasture if properly managed.

Capability unit VIIe-4; woodland suitability group adapted species of grasses are grown. Long periods of
3x1. drought are common. Irrigation is not feasible. Seed-
AhF-Aguilita stony clay loam, 20 to 60 percent ing and fertilizing and clearing of brush for pasture
slopes. This steep and very steep soil is on side slopes are difficult and costly.
and ridges in the semiarid area. It generally is in This soil has been mostly in brush and brushy pas-
areas of more than 100 acres. It is similar to the soil ture of very low carrying capacity. It has severe limita-
described as typical of the series, except that stones tions for cultivation because of slope, depth to soft
and rocks cover 40 to 60 percent of the surface. limestone, the erosion hazard, and the large amount
Included with this soil in mapping are a few hilltops of stones and rocks. This soil should be kept under
where stones and rocks cover more than 80 percent of permanent vegetation.
the surface. Also included are some severely eroded Capability unit VIIs-2; woodland suitability group
soils on ridges that have soft limestone in the surface 3x1.
layer.
Runoff on this soil is rapid to very rapid, and erosion Alonso series
is a hazard. The soil is not suitable for cultivation.
Because rainfall is low and is poorly distributed, the The Alonso series consists of well drained, steep to
use of this soil is largely restricted to range, but few very steep soils on side slopes, foot slopes, and hilltops







PONCE AREA OF SOUTHERN PUERTO RICO 11
of the strongly dissected humid uplands. Slope ranges horizon is saprolite; very strongly acid;
from 20 to 60 percent. These soils formed in fine tex- gradual wavy boundary.
tured residuum of highly weathered pinkish volcanic C-53 to 60 inches; variegated colors of the clay
rock. The annual rainfall ranges from 80 to 90 inches. saprolite; reddish brown, red, very dark
The annual temperature ranges from 720 to 740 F. gray, pale green, and white; massive;
In a representative profile, the surface layer is dark friable, slightly sticky and plastic; very
reddish brown clay about 6 inches thick. The subsoil strongly acid.
is about 47 inches thick. In the upper 11 inches it is The solum is 40 to 60 inches thick. The Ap horizon
dusky red, firm clay; in the 16 inches below that it is ranges from dark reddish brown (5YR 3/3) to dusky
dark reddish brown, firm clay; in the next 15 inches red (2.5YR 3/2). The B2t horizon ranges from dark
it is dark reddish brown and dark red, firm clay; and reddish brown (5YR 3/4) to dusky red (2.5YR 3/2).
in the lowermost 6 inches it is dark reddish brown and The structure of the B2 horizon ranges from weak to
red friable clay. The substratum between depths of 53 moderate and fine to medium subangular blocky. The
and 60 inches is reddish brown, red, very dark gray, B3 horizon is 10 to 35 percent saprolite.
pale green, and white, friable clay. The Alonso soils are on the same landscape as the
These soils are moderately permeable. They have Daguey, Humatas, Consumo, and Morado soils. The
moderate to high available water capacity and moder- Alonso soils have a thicker B2t horizon than the Con-
ate natural fertility. Because of the high content of sumo soils, and the color of their B2t horizon has a
clay, they are difficult to work. The organic-matter lower chroma than that of the Daguey and Humatas
content is moderate, and crops respond well to fer- soils. The Alonso soils are deeper to semiconsolidated
tilizer. Runoff is rapid to very rapid, volcanic rock than the Morado soils.
Alonso soils have been planted to food crops, coffee, AnE2-Alonso clay, 20 to 40 percent slopes, eroded.
and pasture for many years. They are well suited to This is a steep soil on side slopes and hilltops of the
tanniers, plantains, bananas, yams, dasheens, and strongly dissected humid uplands. It is generally in
pangolagrass and stargrass. They are also suited to use areas of about 50 to 100 acres. Its profile is the one
as woodland. described as representative of the series.
Representative profile of Alonso clay, 20 to 40 per- Included with this soil in mapping are small spots,
cent slopes, eroded, about 15 meters east of kilometer mostly along drainageways, of soils that have slopes
marker 67 on Highway 135: greater than 40 percent. Also included are some soils,
Ap-0 to 6 inches; dark reddish brown (5YR on narrow foot slopes, that have slopes of 12 to 20 per-
3/3) clay; weak medium subangular cent.
blocky structure parting to granular; Runoff is rapid, and erosion is a hazard because of
firm, slightly sticky and plastic; many the steep slopes. Deep gullies are common in drainage-
fine roots, very strongly acid; clear ways. Slippage is common especially on roadbanks and
smooth boundary. in ditches and drainageways. Some measures for con-
B21t-6 to 16 inches; dusky red (10R 3/2) clay; trolling erosion are needed if this soil is to be used for
moderate medium subangular blocky cultivated crops. This soil is difficult to work because
structure; firm, slightly sticky and plas- of the stickiness and plasticity of the clay. It should be
tic; many fine roots; few thin patchy tilled at optimum moisture content to prevent big clods
clay films; very strongly acid; clear from forming. The soil has a deep root zone and is
wavy boundary. medium in fertility. Crops respond well to heavy ap-
B22t-16 to 25 inches dark reddish brown plications of lime and fertilizer. The use of machinery
(2.5YR 3/4) clay; moderate fine and me- is not feasible on this soil.
dium subangular blocky structure; firm, This soil has some limitations for cultivated crops
slightly sticky and plastic; common fine because of the steep slopes, rapid runoff, and the haz-
roots; many thin patchy clay films; very ard of erosion. If crops are rotated and lime and fer-
strongly acid; clear wavy boundary. tilizer are applied and if practices that help control
B23t-25 to 32 inches; dark reddish brown erosion are used, this soil is suited to all the crops
(2.5YR 3/4) clay; moderate fine suban- grown in the area.
gular blocky structure; firm, slightly This soil has been planted to a variety of crops in-
sticky and plastic; few fine roots; few cluding shade-grown coffee, plantains, yams, and tan-
patchy clay films; very strongly acid; niers. Some areas are in brush; others are in native
clear wavy boundary. and adapted grasses. Pangolagrass and stargrass grow
B24t-32 to 47 inches; 90 percent dark reddish well on this soil. Controlling the stocking rate helps
brown (5YR 3/3) and 10 percent dark prevent overgrazing and leaves a good stand of grass.
red (2.5YR 3/6) clay; weak fine and Capability unit IVe-1; woodland suitability group
medium subangular blocky structure; 2cl.
firm, slightly sticky and plastic; few fine AnF2-Alonso clay, 40 to 60 percent slopes, eroded.
roots; few thin patchy clay films; very This is a very steep soil on side slopes and narrow
strongly acid; clear wavy boundary. ridges of the humid uplands. It generally is in areas of
B3-47 to 53 inches; dark reddish brown '(5YR more than 100 acres. Except for having a slightly thin-
3/3) and red ((2.5YR 3/6) clay; weak ner solum, this soil is similar to the one described as
fine subangular blocky structure; fri- representative of the series. It has been greatly af-
able, slightly sticky and plastic; very fected by erosion and slippage.
few thin patchy clay films; 15 percent of Included with this soil in mapping are soils, on a







12 SOIL SURVEY

few rounded hilltops, that have slopes of less than 40 weathered volcanic rock fragments;
percent. massive; neutral.
Because of the steep slopes, runoff is very rapid and R-17 inches; hard, semiconsolidated volcanic
erosion is a hazard. Deep gullies are common in drain- rock.
ageways. Slippage is common especially on roadbanks The solum is 9 to, 14 inches thick. The Ap horizon
and in ditches and drainageways. Liming and fertiliz- has hue of 10YR, value of 3 and 4, and chroma of 2
ing are costly and difficult on this soil, and ditches are and 4. The B2 horizon has hue of 7.5YR and 10YR,
difficult to lay out, construct, and maintain. This soil value of 3 and 4, and chroma of 3 and higher. It has
has a deep root zone. weak, fine, and medium subangular blocky to granular
This soil generally is not suitable for cultivation be- structure. The Ap and B2 horizons are neutral to
cause of the steep slopes, very rapid runoff, and erosion slightly acid. Depth to the semiconsolidated rock
hazard. It is suited to woodland use and to native ranges from 12 to 20 inches. The fine volcanic frag-
pasture. ments range from 20 to 30 percent in the Ap horizon
This soil has been planted to shade-grown coffee, and from 30 to 40 percent in the B2 horizon.
bananas, and oranges. Most of the coffee farms have Caguabo soils are on the same landscape as the
been abandoned and are now in brush. Some areas of Mucara, Maraguez, Morado, and .Quebrada soils.
this soil are in native pasture of low carrying capacity, Caguabo soils have hard, semiconsolidated volcanic
and others are in brushy pasture, rock at a depth of 12 to 20 inches, and volcanic frag-
Capability unit VIe-1; woodland suitability group ments make up 30 to 40 percent of their B2 horizon.
3cd. The Mucara, Maraguez, Morado, and Quebrada soils
are deeper to volcanic rock and have fewer volcanic
Caguabo series fragments than Caguabo soils. Unlike the Morado
soils, which have a dark reddish gray surface layer,
The Caguabo series consists of well drained, moder- the Caguabo soils have a dark yellowish brown surface
ately steep to very steep soils on short side slopes and layer.
narrow ridgetops of the strongly dissected humid up- CbF2-Caguabo gravelly clay loam, 20 to 60 percent
lands. The soils are shallow to hard volcanic rock. slopes, eroded. This steep and very steep soil is on short
Slope ranges from 20 to 60 percent. These soils formed side slopes and narrow ridges on the humid uplands. It
in moderately fine textured residuum of weathered generally is in areas of more than 500 acres. It is the
basic volcanic rock. The annual rainfall ranges from soil described as representative of the series.
75 to 85 inches, and the temperature ranges from 740 Included in mapping are very small areas of soils
to 760 F. that have stones and boulders on the surface and a
In a representative profile, the surface layer is dark few areas of soils that do not have gravel in the surface
yellowish brown gravelly clay loam about 5 inches layer.
thick. The subsoil, between depths of 5 and 12 inches, Runoff is rapid and very rapid, and erosion is a haz-
is dark yellowish brown, firm, slightly sticky and ard because of the steepness of the slopes. The shallow-
slightly plastic, gravelly clay loam. The substratum, ness to hard rock limits root penetration. Ditches are
between depths of 12 and 17 inches, consists of highly difficult to lay out, construct, and maintain because of
weathered and partly weathered volcanic rock frag- steep slopes and shallowness to hard rock. Fertilizing
ments. The semiconsolidated volcanic rock is at a depth is costly and difficult.
of 17 inches. This soil is not suitable for cultivation. The use of
These soils are moderately permeable. They have a this soil is restricted largely to grazing because of
low available water capacity and high natural fertility, steep and very steep slopes, rapid and very rapid run-
The root zone is restricted. Runoff is rapid to very off, the effects of past erosion, the shallowness to rock,
rapid, and the soils are highly susceptible to erosion. and the erosion hazard. Deferred grazing helps control
Cagua:bo soils have been in native pasture. Small and erosion.
scattered patches have been planted to shallow-rooted A large acreage of this soil has been in brushy wood-
crops. Large areas are in brush, land and brushy pasture for many years. There are
Representative profile of Caguabo gravelly clay small spots of native pasture of low carrying capacity.
loam, 20 to 60 percent slopes, eroded, 100 meters west In some of the less steep areas this soil is planted to
of kilometer marker 8.75 on Highway 503: pigeonpeas and other food crops.
Ap-0 to 5 inches; dark yellowish brown (10YR Capability unit VIIs-3; woodland suitability group
3/4) gravelly clay loam; moderate fine 4d1.
granular structure; firm, slightly sticky CdF-Caguabo.Rock land complex, 20 to 60 percent
and slightly plastic; many fine roots; slopes. This steep and very steep complex is on side
neutral; clear smooth boundary. slopes and narrow ridges on the humid volcanic up-
B-5 to 12 inches; dark yellowish brown (10YR lands. The Caguabo soil makes up about 60 percent of
3/4) gravelly clay loam; weak fine sub- the complex, and Rock land makes up 40 percent. The
angular blocky structure parting to gran- areas generally are more than 500 acres in size. The
ular structure; firm, slightly sticky and Caguabo soil is similar to the soil described as repre-
slightly plastic; common fine roots; 35 sentative of the series. Rock land consists of areas
percent, by volume, fine volcanic rock where volcanic rock, boulders, and cobbles cover 90 to
fragments; neutral; gradual wavy 100 percent of the surface. The soils between the rocks
boundary. are not classified and vary in depth, texture, and color.
C-12 to 17 inches; highly weathered and partly The Caguabo soil and Rock land occur in such an







PONCE AREA OF SOUTHERN PUERTO RICO 13
intricate pattern that mapping them separately at the C-19 to 27 inches; highly weathered volcanic
scale of the soil map was not practical. rock; neutral.
Because of shallowness to hard rock, steepness of R-27 inches; semiconsolidated volcanic rock.
slopes, and the large amount of rocks, cultivating these The solum is 14 to 24 inches thick. The Ap horizon
areas is not feasible. Most of the acreage has been in has value of 3 or 4 and chroma of 2 or 3. The B2 hori-
brush and brushy pasture. Clearing these areas is too zon has value of 3 or higher and chroma of 2 to 4. It
costly and impractical. This complex provides good has weak, medium or coarse, subangular blocky struc-
habitat for wildlife. ture. The B3 horizon is clay loam or silty clay loam.
Capability unit VIIs-3; not in a woodland suitabil- Depth to the semiconsolidated rock ranges from 20 to
ity group. 36 inches.
The Callabo soils are on the same landscape as the
Callabo series Jacana, Guanabano, Juana Diaz, and Llanos soils. The
Callabo soils are coarser textured than the Jacana
The Callabo series consists of well drained, moder- soils. Unlike the Guanabano soils, Callabo soils are non-
ately steep to very steep soils on foot slopes, long and calcareous. The Callabo soils have a finer textured B
short side slopes, hilltops, and ridgetops in the semi- horizon than the Juana Diaz soils. The Callabo soils
arid uplands. Slope ranges from 12 to 60 percent. These are coarser textured and shallower to rock than the
soils formed in moderately fine textured residuum of Llanos soils.
weathered volcanic rock. The annual rainfall ranges CoD-Callabo silty clay loam, 12 to 20 percent slopes.
from 25 to 50 inches, and the temperature ranges from This is a moderately steep soil on side slopes, foot
780 to 800 F. slopes, and rounded hilltops in the semiarid uplands.
In a representative profile, the surface layer is very It generally is in areas of about 20 to 50 acres. It is
dark grayish brown silty clay loam about 5 inches similar to the soil described as representative of the
thick. The subsoil is about 14 inches thick. In the upper series, but the surface layer is slightly thicker.
8 inches it is dark brown and very dark grayish brown, Included with this soil in mapping are Llanos clay
firm silty clay loam, and in the lower 6 inches it is dark in narrow strips along drainageways, Jacana clay on
yellowish-brown, friable clay loam. The substra- short foot slopes, and some severely eroded soils on
tum, between depths of 19 and 27 inches, is highly hilltops.
weathered volcanic rock. Semiconsolidated rock is at a Erosion is a hazard because of the slope, and some
depth of 27 inches. measures for controlling erosion are needed if crops
These soils are moderately permeable. They have low are to be grown. The soil is easily worked, and crops
available water capacity and high natural fertility. The respond well to fertilizer. Long periods of drought are
organic-matter content is high in the surface layer, common. Because rainfall is low and poorly distributed
Runoff is medium to very rapid, throughout the year, the choice of plants and the time
The Callabo soils have been in native pasture for of year for planting are limited. Irrigation is not feasi-
many years. They are well suited to guineagrass and ble because of the slope.
Angletongrass. In many places the lower slopes and This soil is not suitable for cultivation because of
the steep slopes are plowed and planted to food crops. the slope, medium runoff, and the poor distribution of
There are small patches of brush. rainfall. It is suitable for grazing, but there are few
Representative profile of Callabo silty clay loam, 20 suited species of grass. Grazing should be deferred to
to 40 percent slopes, 100 meters west of kilometer protect the soil.
marker 2.3 on Highway 512: A large acreage of this soil is in native pasture,
Ap-0 to 5 inches; very dark grayish brown mainly guineagrass and Angletongrass. During the
(10YR 3/2) silty clay loam; moderate short rainy season, some areas are planted to pigeon-
medium granular structure; friable, peas, corn, pumpkins, and other food crops. Other
slightly sticky and slightly plastic; many areas are in brushy pastures of low carrying capacity.
fine roots; 10 percent angular volcanic Capability unit IVe-3; woodland suitability group
rock fragments; few worm holes; slightly 3d1.
acid; clear smooth boundary. CoE-Callabo silty clay loam, 20 to 40 percent slopes.
B2-5 to 13 inches; 70 percent dark brown This is a steep soil generally in areas of more than 100
(10YR 4/3) and 30 percent very dark acres on side slopes and ridges in the semiarid uplands.
grayish brown (10YR 3/2) silty clay It is the soil described as representative of the series.
loam; weak medium and coarse suban- Included with this soil in mapping, especially on
gular blocky structure; firm, slightly hilltops, are small excessively eroded areas where the
sticky and slightly plastic; common fine surface layer has been washed away and material from
roots; 10 percent angular volcanic rock the subsoil is exposed. Also included are some areas
fragments; few worm holes; neutral; that have a large amount of rocks and boulders on the
clear wavy boundary. surface and some small areas, mainly along drainage-
B3--13 to 19 inches; dark yellowish brown ways, where slopes are more than 40 percent.
(10YR 4/4) clay loam; weak coarse sub- Because rainfall is low and poorly distributed, the
angular blocky structure; friable, choice of pasture plants is limited. Irrigation is not
slightly sticky and slightly plastic; few feasible. The layout, establishment, and maintenance
fine roots; 15 percent fine angular vol- of ditches is difficult and expensive. Fertilizer is rarely
canic rock fragments; neutral; clear used because of the high cost of application.
wavy boundary. This soil is not suitable for cultivation, because of







14 SOIL SURVEY

the steep slopes, rapid runoff, hazard of erosion, and These soils are slowly permeable. They have a high
effects of past erosion. It is better suited to range than available water capacity, high natural fertility, and
to most other uses. Grazing should be deferred, and a high organic matter content. Runoff is slow. The soils
permanent cover of vegetation should be maintained, are difficult to work. If irrigated, they are well suited
A large acreage of this soil is in brushy pasture and to sugarcane. They have been planted to this crop for
weeds. Some areas are in brush, and others are in many years.
guineagrass and Angletongrass. A few areas are in Representative profile of Cintrona clay, 46 meters
pigeonpeas. In past years many areas were planted east of a dirt road which is 1.3 kilometers north of
to tobacco and corn. kilometer marker 113 of Highway 1:
Capability unit VIe-4; woodland suitability group Ap-0 to 8 inches; very dark gray (10YR 3/1)
3d1. clay; weak fine and medium granular
CoF2-Callabo silty clay loam, 40 to 60 percent structure; firm, sticky and plastic; many
slopes, eroded. This very steep soil is on side slopes and fine roots; common fine volcanic rock
very narrow ridges in the semiarid uplands. It gener- and limestone fragments; strong effer-
ally is in areas of more than 100 acres. It is similar to vescence; clear smooth boundary.
the soil described as representative of the series, but Big-8 to 16 inches; dark gray (10YR 4/1) clay;
it has a thinner surface layer and subsoil. few fine faint dark gray (N 4/0) and
Included with this soil in mapping are a few areas few fine distinct dark yellowish brown
that have a large number of boulders and stones on (10YR 3/4) mottles; weak medium sub-
the surface. Also included are small excessively eroded angular blocky structure; firm, sticky
areas where the highly weathered volcanic rock is on and plastic; many fine roots; common
the surface and a few areas where slopes are less than fine volcanic rock and limestone frag-
40 percent. ments; few shell fragments; strong ef-
Because rainfall is low and poorly distributed fervescense; clear smooth boundary.
throughout the year, the pasture species growing on B2gca-16 to 24 inches; dark gray (10YR 4/1)
this soil are limited. The use of fertilizer is costly and clay; few fine distinct dark yellowish
impractical. Ditches are difficult to lay out, establish, brown (10YR 3/4) mottles, common me-
and maintain because of very steep slopes and the shal- dium faint dark gray (N 4/0) mottles,
lowness of the soil. Deep gullies are common in drain- and fine prominent dark greenish gray
ageways. (5GY 4/1) mottles; weak coarse suban-
This soil is largely limited to grazing because of the gular blocky structure; firm, sticky and
very steep slopes, very rapid runoff, hazard of erosion, plastic; many decayed roots; common
and effects of past erosion. Grazing should be deferred fine volcanic rock fragments; numerous
to keep a good cover of vegetation and to control ero- soft calcium carbonate accumulations;
sion. violent effervescence; clear smooth
This soil has been mostly in brushy pasture of low boundary.
carrying capacity. Some areas are in brush, and others B3g-24 to 31 inches; very dark grayish brown
are in guineagrass and Angletongrass. A small acreage (10YR 3/2) clay; few fine faint dark
has been planted to pigeonpeas and tobacco, despite yellowish brown (10YR 3/4) mottles
the slope, and few fine prominent black (10YR
Capability unit VIIe-3; woodland suitability group 2/1) mottles; weak medium subangular
4d2. blocky structure; firm, sticky and plas-
tic; many decayed roots; common fine
Cintrona series volcanic rock fragments; violent effer-
vescence; clear smooth boundary.
The Cintrona series consists of poorly drained, cal- C1g-31 to 38 inches; very dark grayish brown
careous, nearly level soils on slightly concave terrain (10YR 3/2) clay; few fine prominent
in the flood plains of the semiarid area. Slopes range dark greenish gray (5G 4/1) mottles,
from 0 to 2 percent. These soils formed in fine textured many medium distinct very dark gray
and moderately fine textured sediment of mixed origin (N 3/) mole, ad ine f dark ye
that washed from volcanic and limestone hills. The Nlowsh bon ( ) mottles dark yel-
water table is at a depth of 36 to 60 inches. The annual lowish brown (10YR 4/4) mottles; mas-
rainfall ranges from 25 to 40 inches, and the tempera- sive; firm, sticky and plastic; many
ture ranges from 780 to 800 F. decayed roots; violent effervescence;
In a representative profile, the surface layer is very abrupt smooth boundary.
dark gray clay about 8 inches thick. The subsoil is C2g-38 to 46 inches; 60 percent dark greenish
about 23 inches thick. In the upper 8 inches it is dark gray (5G 4/1), 15 percent greenish gray
gray, firm clay and has dark yellowish brown mottles. (5G 5/1), 10 percent dark gray (5Y
In the 8 inches below that it is dark gray, firm clay 4/1), 10 percent very dark gray (N 3/0),
and has yellowish brown and dark greenish gray mot- and 5 percent dark yellowish brown
ties; and in the next 7 inches it is very dark grayish (10YR 4/4) clay; massive; firm, slightly
brown, firm clay and has dark yellowish brown and sticky and plastic; many decayed roots;
black mottles. The mottled substratum, between depths violent effervescence; abrupt smooth
of 31 and 60 inches, is mainly very dark grayish boundary.
brown, dark greenish gray, and dark gray clay. C3g-46 to 60 inches; dark greenish gray (5GY







PONCE AREA OF SOUTHERN PUERTO RICO 15
4/1) clay; few fine prominent dark yel- They are difficult to work. Runoff is slow. If properly
lowish brown (10YR 4/4) mottles and drained and irrigated, Constancia soils are suitable for
few fine distinct light olive brown (2.5Y sugarcane. They have been planted to this crop for
5/6) mottles; massive; firm, slightly many years.
sticky and plastic; strong effervescence. Representative profile of Constancia silty clay, 2.6
The solum is 24 to 38 inches thick. If the soil is kilometers south of kilometer marker 125.1 on High-
drained, the depth to the water table ranges from 36 way 1:
to 60 inches. The A horizon has hue of 10YR, value of Ap-0 to 12 inches; very dark grayish brown
2 or 3, and chroma of 1. The B horizon has hue of 10YR (10YR 3/2) silty clay; weak fine and
or 2.5Y, value of 3 and 4, and chroma of 1 or 2. Its medium granular structure; firm,
structure is weak medium to weak coarse subangular slightly sticky and plastic; many fine
blocky. Effervescence is strong to violent throughout roots; few fine volcanic fragments;
the profile, slightly compacted; strong efferves-
Cintrona soils are on the same landscape as the cence; abrupt smooth boundary.
Cortada, Jacaguas, Machuelo, San Anton, and Con- B1-12 to 17 inches; very dark grayish brown
stancia soils. Cintrona soils are more poorly drained, (10YR 3/2) silty clay; few fine distinct
have a darker colored surface layer, and are finer tex- yellowish brown (10YR 5/6) mottles and
tured than the Cortada, Jacaguas, San Anton, and Con- common fine distinct dark gray (5Y
stancia soils; they have a darker colored surface layer 4/1) mottles; weak fine and medium
than the Machuelo soils, subangular blocky structure; firm,
Cr-Cintrona clay. This nearly level soil is on slightly sticky and plastic; many fine
slightly concave slopes in the flood plains of the semi- roots; few fine volcanic fragments;
arid area. It is generally in areas of about 20 to 50 strong effervescence; clear smooth
acres. Slopes are 0 to 2 percent, boundary.
Included with this soil in mapping are a few small B2ca-17 to 24 inches; 30 percent very dark gray-
areas of Machuelo clay and a few spots that are saline. ish brown (10YR 3/2), 30 percent yel-
Runoff is slow, and the soil is not subject to erosion. lowish brown (10YR 5/6), 30 percent
It can be cropped intensively without soil loss, if prop- dark gray (5Y 4/1), and 10 percent dark
early drained and irrigated. It is subject to flooding in yellowish brown (10YR 3/4) silty clay;
some years, generally from August to October. Because dark grayish brown (10YR 4/2) when
of slow permeability, this soil may be saturated for crushed; weak medium and coarse sub-
long periods after heavy rains. angular blocky structure; firm, slightly
Land leveling and smoothing are difficult and costly sticky and plastic; few soft small
because of the poor workability of the soil. The soil rounded calcium carbonate accumula-
should be worked at the optimum moisture content. tions; few fine roots; few fine volcanic
Crops on this soil respond well to fertilizer, fragments; few fine shell fragments;
This soil has been in sugarcane for many years. If strong effervescence; clear smooth
properly drained and irrigated, it is suitable for sugar- boundary.
cane and rice. B3ca-24 to 29 inches; 40 percent very dark gray-
Capability unit IIIw-1, irrigated; VIs-2, not irri- ish brown (10YR 3/2), 40 percent dark
gated. Not in a woodland suitability group. gray (5Y 4/1), 15 percent yellowish
brown (10YR 5/6), and 5 percent dark
Constancia series yellowish brown (10YR 3/4) silty clay;
weak medium subangular blocky struc-
The Constancia series consists of somewhat poorly ture; firm, slightly sticky and plastic;
drained, calcareous, nearly level soils on flood plains in few fine roots; few fine volcanic frag-
the semiarid area. Slope ranges from 0 to 2 percent, ments; few soft small rounded calcium
These soils formed in recent fine-textured sediment of carbonate accumulations; few fine shell
mixed origin that washed from volcanic and limestone fragments; few fine limestone frag-
hills. The water table is at a depth of 36 to 60 inches. ments; strong effervescence; clear
The annual rainfall ranges from 25 to 40 inches, and smooth boundary.
the temperature ranges from 780 to 800 F. Clg-29 to 37 inches; dark gray (5Y 4/1) clay;
In a representative profile, the surface layer is very many medium distinct yellowish brown
dark grayish brown silty clay about 12 inches thick. (10YR 5/6) and common medium dis-
The subsoil is about 17 inches thick. In the upper 5 tinct very dark grayish brown (10YR
inches it is very dark grayish brown, firm silty clay 3/2) mottles; firm, sticky and plastic;
and has yellowish brown and dark gray mottles; in the few fine roots; few fine volcanic frag-
lower 12 inches it is very dark grayish brown, yellow- ments; few fine shell fragments; few
ish brown, dark gray, and dark yellowish brown, firm fine limestone fragments; strong effer-
silty clay. The mottled substratum, between depths of vescence; clear smooth boundary.
29 and 65 inches, is mainly dark gray and yellowish C2g-37 to 50 inches; dark gray (5Y 4/1) and
brown, firm clay. brownish yellow (10YR 6/6) clay; few
Constancia soils are slowly permeable. They have a fine distinct dark greenish gray (5BG
moderate to high available water capacity, high nat- 4/1) and few fine distinct dark yellowish
ural fertility, and a high content of organic matter. brown (10YR 3/4) mottles; massive;







16 SOIL SURVEY

firm, sticky and plastic; few fine volcanic firm clay, and in the lower 6 inches it is yellowish red,
fragments; few fine shell fragments; red, and brownish yellow, friable silty clay. The sub-
few fine limestone fragments; water stratum, between depths of 20 and 60 inches, is red,
table at depth of 43 inches; strong effer- yellow, brown, and light gray friable silty clay sapro-
vescence; clear smooth boundary. lite.
C3g-50 to 65 inches; 40 percent yellowish brown These soils are moderately permeable. They have a
(10YR 5/4), 20 percent dark gray (5Y high available water capacity and low natural fertility.
4/1), 15 percent dark bluish gray (5B Runoff is very rapid, and the soils are highly suscepti-
4/1), 15 percent bluish gray (5B 5/1), ble to erosion. These soils are difficult to work. Crops
and 10 percent brownish yellow (10YR respond well to fertilizer.
6/6) clay; massive; firm, sticky and plas- Consumo soils have been planted to a number of
tic; few fine volcanic fragments; few crops for many years. They are suited to use as wood-
fine limestone fragments; violent effer- land and native pasture. Many acres are in native pas-
vescence. ture and brush.
The solum is 24 to 38 inches thick. If the soil is Representative profile of Consumo clay, 40 to 60
drained, the depth to the water table ranges from 36 percent slopes, eroded, 300 meters north of kilometer
to 60 inches. The Ap horizon has hue of 10YR, value of marker 7 on Highway 526:
3, and chroma of 2 and 3. The B and C horizons are Ap-0 to 7 inches; reddish brown (5YR 4/4) clay;
silty clay or clay. The B2 horizon ranges in structure weak fine subangular blocky structure;
from weak fine to weak coarse subangular blocky. Ef- firm, slightly sticky and plastic; many
fervescence ranges from strong to violent throughout fine roots; very strongly acid; clear
the profile. smooth boundary.
The Constancia soils are on the same landscape as B2t-7 to 14 inches; red (2.5YR 4/6) clay; mod-
the San Anton, Cortada, Machuelo, and Cintrona soils, erate medium subangular blocky struc-
Constancia soils are finer textured and more poorly ture; firm, slightly sticky and plastic;
drained than San Anton and Cortada soils, and they many fine roots; thin patchy clay films;
are better drained than the Machuelo and Cintrona very strongly acid; clear wavy bound-
soils. ary.
Ct-Constancia silty clay. This is a nearly level soil B3-14 to 20 inches; 40 percent yellowish red
on alluvial fans along the rivers and streams in the (5YR 4/6), 30 percent red (2.5YR 4/6),
semiarid area. It generally is in areas of about 50 to and 30 percent brownish yellow (10YR
200 acres. Slopes are 0 to 2 percent. 6/6) silty clay; weak fine subangular
Included in mapping are a few small areas of blocky structure; friable, slightly sticky
Machuelo clay and San Anton clay loam and a few and plastic; few fine roots; 50 percent of
spots of soils that have coarse textured material below horizon is saprolite; very strongly acid;
a depth of 2 feet. clear wavy boundary.
Runoff is slow; this soil is not subject to erosion. If C-20 to 60 inches; red, yellow, brown, and light
it is properly drained and irrigated, it can be cropped gray silty clay saprolite; massive; fri-
intensively without soil loss. It is subject to flooding able, slightly sticky and plastic; very
in some years, generally from August to October. Be- strongly acid; original rock structure is
cause of slow permeability, this soil may be saturated visible.
after heavy rains. Occasionally there are long periods The solum is 14 to 24 inches thick. The Ap horizon
of drought. has hue of 5YR and 2.5YR, value of 4, and chroma of
Workability of this soil is poor. Land leveling and 4 and higher. The B2t horizon has hue of 5YR and
smoothing are costly and difficult because the clay is 2.5YR, value of 4, and chroma of 6 and higher. The C
sticky and plastic. Tillage should be done and ma- horizon is silty clay or clay.
chinery should be used at the optimum moisture con- Saprolite makes up 40 to 60 percent of the B3
tent. Crops respond well to fertilizer, horizon. The B2t horizon ranges in structure from
If properly drained and irrigated, this soil can be weak to moderate and fine to medium subangular
planted to sugarcane and rice. blocky.
Capability units IIw-1, irrigated, and IIIc-2 non- Consumo soils are on the same landscape as Daguey,
irrigated; not in a woodland suitability group. Humatas, Alonso, and Morado soils. They have a thin-
ner B2t horizon than that of Daguey, Humatas, and
Consumo series Alonso soils, and they are deeper to rock than Morado
soils.
The Consumo series consists of well drained, very CuF2-Consumo clay, 40 to 60 percent slopes
steep soils on side slopes and narrow ridges of the eroded. This is a very steep soil on side slopes and nar-
strongly dissected humid uplands. Slope ranges from row ridgetops of the humid uplands. It generally is in
40 to 60 percent. These soils formed in fine textured areas of more than 500 acres.
residuum of basic volcanic rock. The annual rainfall Included in mapping are some areas of Humatas
ranges from 80 to 90 inches, and the temperature clay, 40 to 60 percent slopes, eroded. Also included are
ranges from 740 to 760 F. areas of Consumo soils that have slopes of 20 to 40
In a representative profile, the surface layer is red- percent and areas of severely eroded soils on ridges
dish brown clay about 7 inches thick. The subsoil is where the substratum is exposed at the surface.
about 13 inches thick. In the upper 7 inches it is red, Runoff is very rapid because of the steep slopes.







PONCE AREA OF SOUTHERN PUERTO RICO 17

Erosion is a hazard. Slippage is a hazard on roadbanks strong effervescence; clear wavy bound-
and in ditches and drainageways. Because of the steep ary.
slopes, applying lime and fertilizer is difficult and C2-38 to 48 inches; brown (10YR 4/3) silty clay
costly. Diversion ditches are difficult to lay out, con- loam; massive; friable, slightly sticky
struct, and maintain. This soil has a deep root zone. and plastic; few fine roots; violent ef-
In some areas this soil is used for shade-grown cof- fervescence; abrupt smooth boundary.
fee, bananas, and oranges. Yields generally are low. A C3-48 to 68 inches; brown (10YR 4/3) silt loam;
large acreage is in brushy trees and brushy pasture. massive; friable, slightly sticky and
Some areas are in native pasture of low carrying ca- plastic; few fine roots; strong efferves-
pacity. cence.
This soil is suitable only for use as woodland and The solum is 24 to 34 inches thick. The Ap, B2, and
native pasture because of the steep slopes, very rapid B3 horizons have hue of 10YR, value of 2 or 3, and
runoff, and the erosion hazard. chroma of 3. The C horizon has hue of 10YR, value of
Capability unit VIIe-1; woodland suitability group 3 or 4, and chroma of 3 and 4.
3cd. The C horizon is silt loam or silty clay loam. Ef-
fervescence in the solum is slight to strong, and in the
Cortada series C horizon it is strong to violent.
Cortada soils are on the same landscape as San An-
The Cortada series consists of well drained, calcar- ton, Constancia, Machuelo, and Cintrona soils. Unlike
eous, nearly level soils on flood plains in the semiarid San Anton soils, Cortada soils are calcareous, and they
area. Slope ranges from 0 to 2 percent. These soils are better drained and coarser textured than Con-
formed in medium textured and moderately fine tex- stancia, Machuelo, and Cintrona soils.
tured sediment of mixed origin that washed from vol- Cx-Cortada silty clay loam. This nearly level soil is
canic and limestone hills. The annual rainfall ranges on alluvial fans in the semiarid area. It generally is in
from 25 to 40 inches, and the temperature ranges from areas of 50 to 200 acres. Slopes are 0 to 2 percent.
780 to 800 F. Included in mapping are small areas of the noncal-
In a representative profile, the surface layer is very careous San Anton and Cuyon soils and small spots
dark grayish brown silty clay loam about 10 inches of the somewhat poorly drained Constancia soils.
thick. The subsoil is dark brown, firm silty clay loam Runoff is slow. This soil is not subject to erosion. It
about 18 inches thick. The substratum, between depths can be cropped intensively without loss of soil material.
of 28 and 60 inches, is brown silt loam and silty clay It is subject to flooding in some years, generally from
loam that is friable. August to October. The root zone is deep.
Cortada soils are moderately permeable. They have This soil has a plow layer that is easy to till, and
a moderate available water capacity, high natural fer- land smoothing and leveling are feasible. This soil
utility, and high organic matter content. They are easy needs to be irrigated because rainfall is low and is
to work. Runoff is slow, and these soils are not sus- poorly distributed. Long periods of drought are com-
ceptible to erosion, mon in most years. This soil has a moderate available
Cortada soils are suitable for and have been planted water capacity. It is fertile, and crops respond well to
to sugarcane for many years. Recently, some areas fertilizer. It can be used safely with only ordinary
have been planted to tomatoes and peppers. management practices to maintain productivity and
Representative profile of Cortada silty clay loam, good tilth. The use of machinery is feasible.
75 meters west of kilometer marker 0.8 on Highway This soil has been planted to sugarcane and vege-
536: tables, and it is suited to a wide range of plants if
Ap-0 to 10 inches; very dark grayish brown irrigated.
(10YR 3/2) silty clay loam; weak fine Capability units 1-3, irrigated, and IIc-1, nonirri-
granular structure; firm, slightly sticky gated; not in a woodland suitability group.
and plastic; many fine roots; few shell
fragments; slight effervescence; abrupt
smooth boundary. Cuyon series
B2-10 to 18 inches; dark brown (10YR 3/3) The Cuyon series consists of excessively drained,
silty clay loam; weak medium subangu- nearly level to gently sloping soils that are close to
lar blocky structure; firm, slightly sticky riverbanks in the semiarid area. The slope ranges from
and plastic; many fine roots; few shell 0 to 5 percent. These soils are shallow over sand and
fragments; slight effervescence; clear gravel. They formed in recent medium-textured over
B3--18 to 28 inches; dark brown (10YR 3/3) coarse-textured sediment of mixed origin. The annual
silty clay loam; weak fine and medium rainfall ranges from 25 to 45 inches, and the tempera-
subangular blocky structure; firm, ture ranges from 780 to 800 F.
slightly sticky and plastic; few In a representative profile the surface layer is dark
fine roots; few shell fragments; strong brown loam about 11 inches thick. The substratum,
effervescence; abrupt smooth bound- to a depth of 60 inches, is dark brown, gravelly coarse
ary. sand that is less than 10 percent silt.
Cl-28 to 38 inches; brown (10YR 4/3) silt These soils have rapid permeability and a low avail-
loam; massive; friable, slightly sticky able water capacity. Natural fertility is high in the
and slightly plastic; few fine roots; surface layer. The root zone is restricted by sand and







PONCE AREA OF SOUTHERN PUERTO RICO 17

Erosion is a hazard. Slippage is a hazard on roadbanks strong effervescence; clear wavy bound-
and in ditches and drainageways. Because of the steep ary.
slopes, applying lime and fertilizer is difficult and C2-38 to 48 inches; brown (10YR 4/3) silty clay
costly. Diversion ditches are difficult to lay out, con- loam; massive; friable, slightly sticky
struct, and maintain. This soil has a deep root zone. and plastic; few fine roots; violent ef-
In some areas this soil is used for shade-grown cof- fervescence; abrupt smooth boundary.
fee, bananas, and oranges. Yields generally are low. A C3-48 to 68 inches; brown (10YR 4/3) silt loam;
large acreage is in brushy trees and brushy pasture. massive; friable, slightly sticky and
Some areas are in native pasture of low carrying ca- plastic; few fine roots; strong efferves-
pacity. cence.
This soil is suitable only for use as woodland and The solum is 24 to 34 inches thick. The Ap, B2, and
native pasture because of the steep slopes, very rapid B3 horizons have hue of 10YR, value of 2 or 3, and
runoff, and the erosion hazard. chroma of 3. The C horizon has hue of 10YR, value of
Capability unit VIIe-1; woodland suitability group 3 or 4, and chroma of 3 and 4.
3cd. The C horizon is silt loam or silty clay loam. Ef-
fervescence in the solum is slight to strong, and in the
Cortada series C horizon it is strong to violent.
Cortada soils are on the same landscape as San An-
The Cortada series consists of well drained, calcar- ton, Constancia, Machuelo, and Cintrona soils. Unlike
eous, nearly level soils on flood plains in the semiarid San Anton soils, Cortada soils are calcareous, and they
area. Slope ranges from 0 to 2 percent. These soils are better drained and coarser textured than Con-
formed in medium textured and moderately fine tex- stancia, Machuelo, and Cintrona soils.
tured sediment of mixed origin that washed from vol- Cx-Cortada silty clay loam. This nearly level soil is
canic and limestone hills. The annual rainfall ranges on alluvial fans in the semiarid area. It generally is in
from 25 to 40 inches, and the temperature ranges from areas of 50 to 200 acres. Slopes are 0 to 2 percent.
780 to 800 F. Included in mapping are small areas of the noncal-
In a representative profile, the surface layer is very careous San Anton and Cuyon soils and small spots
dark grayish brown silty clay loam about 10 inches of the somewhat poorly drained Constancia soils.
thick. The subsoil is dark brown, firm silty clay loam Runoff is slow. This soil is not subject to erosion. It
about 18 inches thick. The substratum, between depths can be cropped intensively without loss of soil material.
of 28 and 60 inches, is brown silt loam and silty clay It is subject to flooding in some years, generally from
loam that is friable. August to October. The root zone is deep.
Cortada soils are moderately permeable. They have This soil has a plow layer that is easy to till, and
a moderate available water capacity, high natural fer- land smoothing and leveling are feasible. This soil
utility, and high organic matter content. They are easy needs to be irrigated because rainfall is low and is
to work. Runoff is slow, and these soils are not sus- poorly distributed. Long periods of drought are com-
ceptible to erosion, mon in most years. This soil has a moderate available
Cortada soils are suitable for and have been planted water capacity. It is fertile, and crops respond well to
to sugarcane for many years. Recently, some areas fertilizer. It can be used safely with only ordinary
have been planted to tomatoes and peppers. management practices to maintain productivity and
Representative profile of Cortada silty clay loam, good tilth. The use of machinery is feasible.
75 meters west of kilometer marker 0.8 on Highway This soil has been planted to sugarcane and vege-
536: tables, and it is suited to a wide range of plants if
Ap-0 to 10 inches; very dark grayish brown irrigated.
(10YR 3/2) silty clay loam; weak fine Capability units 1-3, irrigated, and IIc-1, nonirri-
granular structure; firm, slightly sticky gated; not in a woodland suitability group.
and plastic; many fine roots; few shell
fragments; slight effervescence; abrupt
smooth boundary. Cuyon series
B2-10 to 18 inches; dark brown (10YR 3/3) The Cuyon series consists of excessively drained,
silty clay loam; weak medium subangu- nearly level to gently sloping soils that are close to
lar blocky structure; firm, slightly sticky riverbanks in the semiarid area. The slope ranges from
and plastic; many fine roots; few shell 0 to 5 percent. These soils are shallow over sand and
fragments; slight effervescence; clear gravel. They formed in recent medium-textured over
B3--18 to 28 inches; dark brown (10YR 3/3) coarse-textured sediment of mixed origin. The annual
silty clay loam; weak fine and medium rainfall ranges from 25 to 45 inches, and the tempera-
subangular blocky structure; firm, ture ranges from 780 to 800 F.
slightly sticky and plastic; few In a representative profile the surface layer is dark
fine roots; few shell fragments; strong brown loam about 11 inches thick. The substratum,
effervescence; abrupt smooth bound- to a depth of 60 inches, is dark brown, gravelly coarse
ary. sand that is less than 10 percent silt.
Cl-28 to 38 inches; brown (10YR 4/3) silt These soils have rapid permeability and a low avail-
loam; massive; friable, slightly sticky able water capacity. Natural fertility is high in the
and slightly plastic; few fine roots; surface layer. The root zone is restricted by sand and







18 SOIL SURVEY

gravel at a depth of 8 to 12 inches. These soils are easy tops, and foot slopes of the humid volcanic uplands.
to work. Runoff is slow. The soils formed in fine textured residuum of highly
Cuyon soils are well suited to native pasture. Most weathered, basic volcanic rock. The slope ranges from
of the areas have been in guineagrass and Angleton- 12 to 20 percent. The annual rainfall ranges from 70
grass for many years. to 80 inches, and the temperature ranges from 76 to
Representative profile of Cuyon loam, 0 to 5 percent 780 F.
slopes, 40 meters east of kilometer marker 39.05 on In a representative profile, the surface layer is dark
Highway 14: reddish brown clay about 8 inches thick. The subsoil
Ap-0 to 11 inches; dark brown (10YR 3/3) is about 33 inches thick. In the upper 8 inches, it is
loam; weak fine granular structure; fri- reddish brown, firm clay; in the 17 inches below that,
able, slightly sticky and slightly plastic; it is yellowish red firm clay; and in the lowermost 8
many fine roots; few rounded rock frag- inches, it is red and strong brown, friable clay. The
ments, 1 to 2 inches in diameter; neu- substratum, between depths of 41 and 60 inches, is red,
tral; clear irregular boundary. dark red, very pale brown, and yellowish brown clay
Cl-11 to 17 inches; 70 percent medium and saprolite.
coarse gravel, 25 percent coarse sand, These soils are moderately permeable. They have
and 5 percent silt, by volume, moderate to high available water capacity, moderate
C2-17 to 60 inches; dark brown (10YR 3/3) natural fertility, and moderate organic matter content.
gravelly coarse sand that has less than They are difficult to work. Runoff is medium, and the
10 percent silt. soils are somewhat susceptible to erosion. Crops re-
Thickness of the Ap horizon and depth to the coarse spond well to fertilizer.
material range from 8 to 12 inches. The Ap horizon Daguey soils have been used mainly for food crops
has hue of 10YR, value of 2 and 3, and chroma of 3. such as yams, plantains, bananas, and tanniers (fig. 3).
The Ap horizon is neutral to mildly alkaline. The sub- Some areas are in shade coffee, native pasture, and pan-
stratum is 50 to 80 percent gravel. golagrass, and some are suitable for sun-grown coffee.
Cuyon soils are on the same landscape as Jacaguas, Representative profile of Daguey clay, 12 to 20 per-
San Anton, and Cortada soils. Cuyon soils are shal- cent slopes, 250 meters south of kilometer marker 7.6
and Cortada soils, and unlike Cortada soils, they are Ap-0 to 8 inches; dark reddish brown (5YR
noncalcareous and are neutral to mildly alkaline. 3/4) clay; weak medium subangular
CyB-Cuyon loam, 0 to 5 percent slopes. This is a blocky structure; firm, slightly sticky
nearly level soil on small alluvial fans close to rivers and plastic; many fine roots; strongly
and drainageways in the semiarid area. It generally is acid; clear smooth boundary.
in areas of 20 to 50 acres. B21t-8 to 16 inches; reddish brown (5YR 4/4)
Included in mapping are a few small areas of River- clay; moderate fine and medium suban-
wash and small areas that have rocks and boulders on gular blocky structure; firm, slightly
the surface. sticky and plastic; many fine roots; thin
Runoff is slow, and this soil is not subject to erosion. discontinuous clay films; strongly acid;
It is subject to frequent flooding, generally in August clear wavy boundary.
to November. Because rainfall is low and is unevenly B22t-16 to 24 inches; yellowish red (5YR 4/6)
distributed throughout the year, there are few adapted clay; moderate fine and medium suban-
kinds of grasses. Furrow irrigation is not feasible be- gular blocky structure; firm, slightly
cause of shallowness to sand and gravel. This soil has a sticky and plastic; many fine roots;
loam layer that can be easily tilled throughout a wide patchy clay films; strongly acid; clear
range of moisture content without big clods forming, wavy boundary.
The available water capacity in the substratum is very B23t-24 to 33 inches; yellowish red (5YR 4/6)
low. clay; weak medium subangular blocky
The root zone is limited because of a lack of mois- structure; firm, slightly sticky and plas-
ture. Land leveling or smoothing is not feasible because tic; few fine roots; patchy clay films;
coarse textured material is near the surface; however, very strongly acid; clear wavy boundary.
shallow plowing is feasible. Unlike the underlying B3-33 to 41 inches; red (2.5YR 4/6) and strong
layer, which does not have plant nutrients, the surface brown (7.5YR 5/8) clay; weak medium
layer of this soil is fertile. brown (7.5YR 5/8) clay weak medium
This soil has mainly been in native pasture grasses subangular blocky structure; friable,
such as pangolagrass and Angletongrass. Because rain- slightly sticky and plastic; 50 percent of
fall is low and furrow irrigation is impractical, the horizon is saprolite; very strongly acid;
use of this soil is restricted mainly to pasture. Some clear wavy boundary.
areas can be planted to vegetables if sprinkler irriga- C-41 to 60 inches; variegated colors of the
tion is used. saprolite as red (2.5YR 4/6), dark red
Capability unit VIs-1; not in a woodland suitability (2.5YR 3/6), very pale brown (10YR
group. 7/4), and yellowish brown (10YR 5/8)
clay; massive; friable, nonsticky and
Daguey series slightly plastic; very strongly acid.
The solum is 30 to 50 inches thick. The B2t horizon
The Daguey series consists of well drained, moder- is 19 to 30 inches thick. The Ap horizon has hue of
ately steep soils on the more stable side slopes, ridge- 7.5YR and 5YR, value of 3 and 4, and chroma of 4 and








PONCE AREA OF SOUTHERN PUERTO RICO 19


































Figure 3.-Yams and bananas, in the background, grow well on Dagney clay, 12 to 20 percent slopes.

higher. Clay films in the B2t horizon range from Some areas are planted to shade-grown coffee. Other
patchy to discontinuous. Structure of the B2t horizon areas are in native pasture and brushy forest. This
ranges from weak to moderate and from medium to soil is suited to all the crops and pasture plants com-
coarse subangular blocky. The B3 horizon is 30 to 60 only grown in the area. Because of slope, runoff, and
percent saprolite. the hazard of erosion, measures to control erosion are
Daguey soils are on the same landscape as Humatas, needed if cultivated crops are grown. Pangolagrass and
Consumo, and Alonso soils. Daguey soils are on the stargrass grow well on this soil. Merkergrass can be
more stable ridges, side slopes, and foot slopes; the planted as green chop.
Humatas soils are on the steeper slopes. Daguey soils Capability unit IIIe-1; woodland suitability group
are more highly weathered than Humatas soils, have 2c2.
a thicker B horizon than Consumo soils, and have a
higher chroma in the B2t horizon than Alonso soils.
DaD-Daguey clay, 12 to 20 percent slopes. This is a Ensenada series
moderately steep soil on stable side slopes, ridgetops,
and foot slopes on the humid volcanic uplands. It gen- The Ensenada series consists of well drained, cal-
erall dd in ma areas o about 20s of Humatas careous, gently sloping to strongly sloping gravelly
Included in mapping are small areas of umof t patased
soils, soils on a few rounded hilltops, and soils on some soils. These soils formed in a mixture of transported
foot slopes where the slope is less than 12 percent. clay and limestone gravel. They are on a truncated
Runoff on this soil is medium, and erosion is a haz- remnant of a fluvial deposit adjacent to the limestone
ard. This soil has a plow layer that is difficult to work hills in the semiarid area. Slope ranges from 2 to 12
because of its high content of clay. It should be tilled percent. The annual rainfall ranges from 20 to 30
at optimum moisture content. The root zone is deep. inches, and the temperature ranges from 780 to 800 F.
This soil generally is deficient in major plant nutrients. In a representative profile, the surface layer is dark
Crops respond well to lime and fertilizer, reddish brown gravelly clay about 5 inches thick. The
This soil has been used for a wide variety of food upper part of the subsoil is dark reddish brown, firm
crops such as tanniers, bananas, plantains, and yams. gravelly clay about 6 inches thick; the lower part, to a








20 SOIL SURVEY

depth of 60 inches, is yellowish red, friable gravelly the large amount of gravel in the soil, irrigation by
clay. furrows is difficult. Ditches are unstable, and a large
These soils are moderately permeable. They have amount of water is needed.
low to moderate available water capacity and high Workability generally is difficult and land smooth-
natural fertility. Because of the large amount of gravel ing or leveling is impractical because of the gravel.
throughout the profile these soils are difficult to work. The root zone is deep. This soil should be shallow
Runoff is slow. plowed. It is fertile, and crops respond well to fertili-
If irrigated, Ensenada soils are suited to sugarcane. zer.
They have been planted to this crop for many years. This soil has been used mainly for sugarcane under
Nonirrigated areas are in native pasture and low irrigation management. Large amounts of water are
brush. needed because of the gravelly layers. Some small
Representative profile of Ensenada gravelly clay, 2 areas where irrigation is not possible are planted to
to 12 percent slopes, 30 meters west of kilometer other food crops. Some measures for controlling ero-
marker 3.75 on Highway 335: sion are needed if cultivated crops are grown. Few
Ap-0 to 5 inches; dark reddish brown (5YR species of grass are adapted to this soil because rainfall
3/3) gravelly clay; moderate fine gran- is low and poorly distributed throughout the year.
ular structure; firm, sticky, and plastic; Capability unit IIIs-1, irrigated, and IVc-5, nonirri-
many fine roots; few cobbles and rock gated; not in a woodland suitability group.
on the surface; 40 percent, by volume,
of horizon is limestone gravel; efferves- Fe series
cence on small limestone fragments;
clear smooth boundary. The Fe series consists of somewhat poorly drained,
B2t-5 to 11 inches; dark reddish brown (5YR calcareous, saline, nearly level soils on alluvial fans
3/4) gravelly clay; moderate fine suban- slightly above flood plains in the semiarid area. Slopes
gular blocky structure; firm, sticky and are 0 to 2 percent. These soils formed in fine textured
plastic; common fine roots; thin patchy sediment that was derived from volcanic and limestone
clay films; 40 percent, by volume, of rock. Annual rainfall is 20 to 30 inches, and the tem-
horizon is limestone gravel; effervescence perature is 780 to 800 F.
on limestone fragments; clear smooth In a representative profile, the surface layer is very
boundary. dark grayish brown firm clay about 8 inches thick. The
B3-11 to 60 inches, yellowish red (5YR 5/8) subsurface layer, between depths of 8 and 14 inches,
gravelly clay; weak fine subangular is very dark grayish brown and dark grayish brown
blocky structure; friable, sticky and clay. The substratum, between depths of 14 and 60
plastic; 60 percent, by volume, of hori- inches, is brown, firm clay that has grayish brown,
zon is rounded and subrounded limestone very dark grayish brown, yellowish brown, dark yel-
gravel with clay and calcium carbonate; lowish brown, and light gray mottles.
violent effervescence throughout the soil Permeability is slow and the available water capac-
mass. ity is high. The content of salts is high. These soils are
The solum is more than 60 inches thick. The content difficult to work. Runoff is slow.
of limestone gravel in the solum ranges from 35 to 60 In most areas these soils are in native grasses, and
percent. The Ap horizon has hue of 7.5YR and 5YR, in some small areas they are in sugarcane. In many
value of 3, and chroma of 2 and 3. The B2t horizon spots they are barren.
has hue of 5YR and 2.5YR, value of 3 to 5, and chroma Representative profile of Fe clay, 2 kilometers north
of 4 and higher. The B2t horizon ranges in structure of kilometer marker 113.1 on Highway 1:
from weak medium to moderate fine and medium sub- A1-0 to 8 inches; very dark grayish brown
angular blocky. (10YR 3/2) clay; massive; firm, sticky
Ensenada soils are in the same area as Aguilita and and plastic; many fine roots; pressure
Tuque soils. They are redder and finer textured than faces; first two inches have very weak
Aguilita soils. Unlike Tuque soils, which are underlain fine granular structure; violent ef-
by indurated caliche, Ensenada soils are underlain by fervescence; clear smooth boundary.
gravelly clay. AC-8 to 14 inches; very dark grayish brown
EnC-Ensenada gravelly clay, 2 to 12 percent slopes. (10YR 3/2) and dark grayish brown
This is a gently sloping to strongly sloping soil on (10YR 4/2) clay; massive; firm, sticky
fluvial deposits adjacent to the limestone hills in the and plastic; many fine roots; pressure
semiarid area. It generally is in areas of about 5 to 50 faces; violent effervescence; clear smooth
acres. Some stones and rock outcrops are common on boundary.
the surface. C1-14 to 21 inches; brown (7.5YR 5/4) clay;
Included in mapping are some areas where the soil common fine distinct very dark grayish
is free of gravel in the surface layer and some small brown (10YR 3/2) mottles; massive;
areas where the soil is free of gravel in both the surface firm, sticky and plastic; common fine
layer and the subsoil. roots; pressure faces; violent efferves-
Runoff is slow, and erosion is a hazard if cultivated cence; clear wavy boundary.
crops are grown. Rainfall is low and poorly distributed C2-21 to 29 inches; brown (7.5YR 5/4) clay;
throughout the year. Irrigation is necessary on this few fine distinct very dark grayish
soil. Long periods of drought are common. Because of brown (10YR 3/2) mottles; massive;







PONCE AREA OF SOUTHERN PUERTO RICO 21

firm, sticky and plastic; few fine roots; coastal plain in the semiarid area. Slopes are 2 to 12
pressure faces and slickensides; violent percent. These soils are at a slightly higher elevation
effervescence; clear wavy boundary. than the soils on flood plains. They formed in fine tex-
C3-29 to 38 inches; brown (7.5YR 5/4) clay; tured sediment derived from volcanic and limestone
common fine distinct very dark grayish rock. Annual rainfall is 30 to 45 inches, and the tem-
brown (10YR 3/2) and common fine perature is 780 to 800 F.
faint grayish brown (10YR 5/2) mot- In a representative profile, the surface layer is very
ties; massive; firm, sticky and plastic; dark grayish brown clay about 8 inches thick. The sub-
pressure faces and slickensides; violent surface layer is about 32 inches thick. In the upper 6
effervescence; clear wavy boundary. inches, it is very dark grayish brown, very firm clay;
C4-38 to 47 inches; brown (7.5YR 5/4) clay; in the 8 inches below that, it is dark brown and very
common fine distinct very dark grayish dark brown, very firm clay; in the 8 inches below that,
brown (10YR 3/2), yellowish brown it is dark yellowish brown, very firm clay; and in the
(10YR 5/6), and few fine distinct light lowermost 10 inches, it is dark brown, very firm clay.
gray (10YR 6/1) mottles; massive; firm, The substratum, between depths of 40 and 60 inches,
sticky and plastic; pressure faces and is dark brown, firm silty clay.
slickensides; lenses of fine sand; violent Permeability is slow, and the available water capac-
effervescence; gradual wavy boundary. ity is high. Natural fertility is high. These soils are
C5-47 to 60 inches; brown (7.5YR 5/4) clay; very difficult to work.
common fine distinct light gray (10YR If they are irrigated, the Fraternidad soils are well
6/1) and dark yellowish brown (10YR suited to sugarcane. In some areas where water for
4/4) mottles; massive; firm, sticky and irrigation is not available these soils are in native pas-
plastic; pressure faces and slickensides; ture.
violent effervescence. Representative profile of Fraternidad clay, 2 to 5
The Al horizon is 6 to 10 inches thick. It has hue of percent slopes, 400 meters west of kilometer marker
7.5YR and 10YR, value of 3, and chroma of 2 and 3. 7.5 on Highway 149:
The C horizon has hue of 7.5YR, value of 4 and 5, and Ap-0 to 8 inches; very dark grayish brown
chroma of 4 and 6. Effervescence is strong to violent (10YR 3/2) clay; weak fine and medium
throughout. subangular blocky structure; firm, sticky
Fe soils are on the same landscape as the Fraterni- and plastic; many fine roots; 1 inch of
dad, Cintrona, Serrano, and Teresa soils. Unlike Fra- self-mulch; neutral; abrupt smooth
ternidad and Cintrona soils, Fe soils are saline boundary.
throughout. They are finer textured than Serrano soils. A12-8 to 14 inches; very dark grayish brown
Fe soils are lighter colored below a depth of 15 inches (10YR 3/2) clay; massive; very firm,
than Teresa soils, and they have pressure faces and sticky and plastic; many fine roots;
slickensides that Teresa soils do not have. many pressure faces; many fine volcanic
Fe-Fe clay. This is a nearly level soil on alluvial rock fragments; mildly alkaline; clear
fans that are slightly above the flood plains in the wavy boundary.
semiarid area. Slopes are 0 to 2 percent. The areas A13-14 to 22 inches; 70 percent dark brown
generally are about 50 to 100 acres in size. (7.5YR 3/2) and 30 percent very dark
Included in mapping are small areas of Fraternidad brown (10YR 2/2) clay; massive; very
clay and Teresa clay. firm, sticky and plastic; few fine roots;
Runoff is slow. The available water capacity is high. many pressure faces; many intersecting
This soil is not subject to erosion. It needs to be slickensides; many fine volcanic rock
drained, fragments; mildly alkaline; clear wavy
The large amount of harmful salts throughout this boundary.
soil limits the use of this soil for crops. Because rain- A14-22 to 30 inches; dark yellowish brown
fall is low and poorly distributed, this soil needs to be (10YR 3/4) clay; massive; very firm,
irrigated. Land leveling or smoothing is difficult be- sticky and plastic; few fine roots; many
cause of the poor workability of this soil. This soil pressure faces; many intersecting slick-
should be tilled at the optimum moisture content. The ensides; neutral; gradual wavy bound-
use of machinery is feasible. ary.
Most areas of this soil are barren because of the high A15-30 to 40 inches; dark brown (10YR 3/3)
salt content. A few areas are in sugarcane, and yields clay; massive; very firm, sticky and plas-
are low. Some areas are in salt-tolerant weeds. tic; decayed roots; few lime splotches;
This soil has severe limitations for crops or pasture many pressure faces; slight efferves-
because the content of soluble salts is high. The cost cence; mildly alkaline; gradual wavy
of reclaiming this soil is high. boundary.
Capability unit VIs-2; not in a woodland suitability AC-40 to 60 inches; dark brown (10YR 4/3)
group, silty clay; massive; firm, sticky and plas-
grop tic; few lime splotches; very few fine
limestone fragments; mildly alkaline.
Fraternidad series The Ap horizon is 7 to 10 inches thick. It has hue of
The Fraternidad series consists of moderately well 10YR and value and chroma of 2 and 3. The AC hori-
drained, gently sloping to strongly sloping soils on the zon has hue of 10YR and 7.5YR, value of 4, and







22 SOIL SURVEY

chroma of 3 and 4. It is clay or silty clay. The Ap hori- Guanabano series
zon ranges from neutral to moderately alkaline.
Fraternidad soils are on the same landscape as Paso The Guanabano series consists of well drained, cal-
Seco, Serrano, Fe, and Teresa soils. Unlike Paso Seco careous, very steep soils on side slopes and rounded
soils, Fraternidad soils do not have gravelly clay layers, hilltops on the semiarid, volcanic uplands. Slopes are
They are finer textured than Serrano soils. Unlike Fe, 40 to 60 percent. These soils formed in moderately fine
Teresa, and Serrano soils, they are nonsaline. textured and fine textured residuum that was derived
FtB-Fraternidad clay, 2 to 5 percent slopes. This is from calcareous volcanic rock.
a gently sloping soil on the coastal plain in the semi- In a representative profile, the surface layer is dark
arid area. This soil is on terraces that are slightly reddish brown clay about 6 inches thick. The subsoil
higher than the river flood plain. The areas generally is about 14 inches thick. In the upper 5 inches, it is
are about 50 to 100 acres in size. This is the soil de- dark reddish brown, firm clay; and in the lower 9
scribed as representative of the series. inches it is reddish brown, firm silty clay loam. The
Included in mapping are areas of Paso Seco clay, substratum, between 20 and 50 inches, is reddish
areas where the surface layer is calcareous, and areas brown, firm silty clay loam, and between depths of 50
where the surface layer is lighter colored, and 60 inches, it is reddish gray, firm gravelly silty
Runoff is slow. Permeability is slow, and the avail- clay loam.
able water capacity is high. The root zone is deep. This Permeability is moderate, and the available water
soil is not subject to erosion and can be cropped inten- capacity is high. Natural fertility is high. These soils
sively. are somewhat difficult to work. Runoff is rapid, and
Because rainfall is low and poorly distributed, this the soils are susceptible to erosion.
soil needs to be irrigated if crops are grown. Land Guanabano soils have been in native pasture for
leveling or smoothing is difficult because of the poor many years, and a few acres are in brush. These soils
workability of this soil. This soil has hard clods when are suited to guineagrass and Angletongrass.
it is dry, and it is sticky and plastic when wet. It should Representative profile of Guanabano clay, 40 to 60
be tilled at the optimum moisture content because the percent slopes, 100 meters south of Ubarris farm silo,
clay is sticky and plastic. This soil is fertile, and crops southwest of kilometer marker 18.15 on Highway 14:
respond well to fertilizer. Ap-0 to 6 inches; dark reddish brown (5YR
In most areas this soil has been planted to sugar- 3/2) clay; moderate medium granular
cane. A few areas are used as native pasture. Adapted structure; firm, slightly sticky and plas-
species of grasses are few because rainfall is low. If tic; many fine roots; many very fine
properly managed and irrigated, this soil is best suited volcanic rock and limestone angular frag-
to sugarcane and rice. ments; 15 percent, by volume, volcanic
Capability units IIs-1, irrigated, and IIIc-1, nonir- and limestone cobbles on the surface;
rigated; not in a woodland suitability group, strong effervescence; clear smooth
FtC2-Fraternidad clay, 5 to 12 percent slopes, boundary.
eroded. This is a strongly sloping soil on the coastal B2t-6 to 11 inches; dark reddish brown (5YR
plain in the semiarid area. This soil is on terraces and 3/2) clay; moderate medium subangular
foot slopes that are slightly higher than the flood plain, blocky structure; firm, slightly sticky
The areas are about 50 to 100 acres in size. This soil is and plastic; many fine roots; few patchy
similar to the one described as representative of the clay films; many very fine volcanic rock
series, except it has a slightly thinner surface layer, and limestone fragments; few medium
Included in mapping are some areas where this soil volcanic rock fragments; strong efferves-
is underlain by soft limestone at a depth of 30 to 40 cence; clear smooth boundary.
inches. Also included are areas where this soil is red- B3ca-ll to 20 inches; reddish brown (5YR 4/3)
dish brown throughout and areas where the surface silty clay loam; weak medium and coarse
layer is calcareous. subangular blocky structure; firm,
Runoff is slow to medium. Permeability is slow, and slightly sticky and plastic; common fine
the available water capacity is high. The root zone is roots; accumulations of fine soft calcium
deep. Erosion is a hazard, and it needs to be controlled carbonate in spheres, coatings, and my-
if cultivated crops are grown. celia shapes on faces of peds; many very
if cultivated crops are grown. fine volcanic rock fragments; violent ef-
Because rainfall is low and poorly distributed this fervescence; clear wavy boundary.
soil needs to be irrigated. It is suited to sprinkler irri- C1-20 to 50 inches; reddish brown (5YR 5/3)
gation. Land leveling or smoothing is very difficult be- silty clay loam; massive; firm, slightly
cause of slope and poor workability. This soil has hard sticky and plastic; violent effervescence;
clods when it is dry, and it is plastic when wet. It clear wavy boundary.
should be tilled at the optimum moisture content. This C2-50 to 60 inches; reddish gray (5YR 5/2)
soil is fertile, and crops respond well to fertilizer, gravelly silty clay loam; massive; firm,
A large acreage is planted to sugarcane, and the rest slightly sticky and plastic; 50 percent,
is in native pasture. Adapted species of grasses are few by volume, subrounded and angular vol-
because rainfall is low. If properly managed and irri- canic rock and limestone fragments; vio-
gated, this soil is best suited to sugarcane. lent effervescence.
Capability units IIIe-2, irrigated, and IVc-1, non- The solum is 16 to 28 inches thick. The surface is
irrigated; not in a woodland suitability group. 10 to 20 percent, by volume, volcanic and limestone







PONCE AREA OF SOUTHERN PUERTO RICO 23

cobbles. The Ap horizon has hue of 5YR and value and crops such as plantains, yams, and tanniers. They are
chroma of 2 and 3. Calcium carbonate accumulations also suited to pangolagrass, stargrass, and guinea-
are between depths of 9 and 16 inches. Semiconsoli- grass.
dated, calcareous volcanic rock is between depths of 60 Representative profile of Humatas clay, 20 to 40 per-
and 80 inches. cent slopes, eroded, 450 meters north of kilometer
Guanabano soils are on the same landscape as marker 72.5 on Highway 135:
Aguilita, Juana Diaz, and Callabo soils. They are red- Ap-0 to 5 inches; dark brown (7.5YR 4/4) clay;
der than those soils. Unlike Aguilita soils, Guanabano weak fine and medium subangular blocky
soils do not have a thick layer of soft limestone. They structure; firm, slightly sticky and
are thicker than Juana Diaz soils, and, unlike Juana slightly plastic; many fine roots; very
Diaz soils, they are calcareous throughout. strongly acid; clear smooth boundary.
GoF-Guanabano clay, 40 to 60 percent slopes. This B21t-5 to 11 inches; 40 percent yellowish red
is a very steep soil on short side slopes and ridgetops (5YR 4/6), 40 percent red (2.5YR 4/8),
on the semiarid, volcanic uplands. The areas gener- and 20 percent dark brown (7.5YR 4/4)
ally are about 50 to 100 acres in size. clay; moderate medium subangular
Included in mapping are small areas of Aguilita blocky structure; firm, slightly sticky
gravelly clay and Callabo silty clay loam. Also included and plastic; common fine roots; many
are ridgetops that have a large percentage of rocks on thin patchy clay films; very strongly
the surface and a few areas on the lower part of slopes acid; clear smooth boundary.
where the slope is less than 40 percent. B22t-11 to 20 inches; red (2.5YR 4/8) clay;
Runoff is very rapid. Permeability and the available moderate medium subangular blocky
water capacity are moderate. This soil is very suscep- structure; firm, slightly sticky and plas-
tible to erosion, tic; common fine roots; many thin
This soil has severe limitations for cultivated crops patchy clay films; very strongly acid;
because of slope and the erosion hazard. A permanent clear wavy boundary.
vegetative cover needs to be maintained. Because rain- B23t-20 to 28 inches; red (2.5YR 4/8) clay;
fall is low and drought periods are frequent and long, weak fine and medium subangular blocky
special pasture management and deferred grazing are structure; firm, slightly sticky and plas-
needed to avoid overgrazing. Few adapted species of tic; few fine roots; common thin patchy
grasses are in this area. This soil is fertile and some- clay films; very strongly acid; clear wavy
what difficult to work. boundary.
Most of the acreage is in native pasture grasses, B3-28 to 40 inches; rubbed color red (2.5YR
including mainly guineagrass and Angletongrass. 4/8) clay; weak fine and medium suban-
Some small areas are in brush. This soil generally is gular blocky structure; firm, slightly
not suitable for cultivation because of slope, very rapid sticky and plastic; few fine roots; few
runoff, and susceptibility to erosion. It is suited to use patchy clay films; 25 percent saprolite;
as range if deferred grazing is used to control erosion. very strongly acid; clear wavy bound-
Capability unit VIIe-3; not in a woodland suitabil- ary.
ity group. C-40 to 60 inches; variegated colors of saprolite;
red (2.5YR 4/8, 4/6), yellowish brown
Humatas series (10YR 5/8), dark red (2.5YR 3/6), and
very pale brown (10YR 7/4) clay; mas-
The Humatas series consists of well drained, steep sive; friable, slightly sticky and slightly
and very steep soils on side slopes and hilltops on plastic; very strongly acid.
strongly dissected, humid uplands. These soils formed The solum is 30 to 52 inches thick. The B2t horizon
in fine textured residuum derived from basic volcanic is 18 to 30 inches thick. The Ap horizon has hue of
rock. Slopes are 20 to 60 percent. The annual rainfall 7.5YR and 5YR, value of 3 and 4, and chroma of 4 and
is 70 to 90 inches, and the temperature is 760 to 780 F. 6. The B2t horizon has hue of 2.5YR, 5YR, and 7.5YR,
In a representative profile, the surface layer is dark value of 4, and chroma of 6 to 8. The B3 horizon is
brown clay about 5 inches thick. The subsoil is about 20 to 40 percent saprolite.
35 inches thick. In the upper 6 inches it is yellowish In some areas, the Humatas soils are in a complex
red, red, and dark brown firm clay, and in the lower with gravelly soils that are too variable to classify.
29 inches it is red, firm clay. The substratum, between Humatas soils are on the same landscape as Daguey,
depths of 40 and 60 inches, is red, yellowish brown, Consumo, and Alonso soils. Humatas soils are not so
dark red, and very pale brown friable clay. highly weathered as Daguey soils, and, unlike Daguey
Permeability is moderate, and the available water soils, they are on the steeper side slopes and on narrow
capacity is moderate to high. Natural fertility is me- hilltops. Humatas soils have a thicker B horizon than
dium. These soils are difficult to work. Runoff is rapid Consumo soils. They have a higher value and chroma
or very rapid, and these soils are susceptible to ero- in the A and B horizons than Alonso soils.
sion. Crops respond well to lime and fertilizer. HmE2-Humatas clay, 20 to 40 percent slopes,
For many years, Humatas soils have been planted to eroded. This is a steep soil on side slopes and ridgetops
a wide variety of food crops. A large acreage is in on strongly dissected, humid uplands. The areas gener-
shade-grown coffee and brush. Other areas are in na- ally are more than 200 acres in size. This is the soil
tive pasture and pangolagrass. These soils are suited described as representative of the series.
to sun-grown and shade-grown coffee and clean-tilled Included in mapping are areas of narrow foot slopes







24 SOIL SURVEY

where the slope is less than 20 percent, areas of Con- practical to separate them in mapping at the scale
sumo clay, and a few areas of Daguey clay on hilltops, used.
Runoff is rapid. Erosion is a hazard. Slippage is Included in mapping are small areas where the soils
common on roadbanks and in ditches and drainage- have rocks and boulders on the surface.
ways. This soil is difficult to work because the slopes Most areas of this map unit are in abandoned coffee
are steep and the clay is sticky and plastic. Hillside trees and brush. A few areas are in shade-grown cof-
ditches and diversions are difficult to lay out, construct, fee and brushy pasture.
and maintain. The root zone is deep. Fertility is me- These soils have severe limitations for cultivated
dium, and crops respond well to heavy and periodical crops and for residential, commercial, industrial, or
applications of lime and fertilizer, recreational uses because of slope, rapid runoff, the
This soil has been used for shade-grown coffee, erosion hazard, and the large content of gravel. These
plantains, tanniers, yams, bananas, and oranges. Some soils are suitable for use as native pasture and wood-
areas have been used as native pasture. Other areas land and for wildlife food and cover.
are in improved pasture, and a large acreage is in Capability unit VIIe-1; woodland suitability group
brush. Most of the coffee farms have been abandoned 3cl.
and are brushy.
This soil can be planted periodically to all the crops Hydraqents
adapted to the humid uplands if erosion is controlled raquents
and large amounts of lime and fertilizer are applied. Hy--Hydraquents. This map unit is in lagoonlike
Pangolagrass and stargrass grow well on this soil. De- areas and in depressions on the flood plains of streams
ferred grazing can help to avoid overgrazing and con- and rivers. The areas generally are about 5 to 20 acres
troCal unit IVe-1; woodlanderosion in size. The water table is at or near the surface most
Capability unit IVe-1; woodland suitability group of the year.
2cl. The high water table severely limits these soils for
HmF2-Humatas clay, 40 to 60 percent slopes, cultivation. Artificial drainage is not feasible because
eroded. This is a very steep soil on side slopes and these soils do not have outlets for drainage. These
narrow ridges on humid uplands. The areas generally soils are best suited to wildlife food and cover.
are more than 200 acres in size. This soil is similar to These soils have severe limitations for residential
the one described as representative of the series, except commercial, industrial, or recreational uses.
it has a slightly thinner surface layer. Capability unit VIIIw-1; not in a woodland suitabil-
Included in mapping are a few areas that have rocks ity group.
and boulders on the surface and some severely eroded
soils on ridges where the substratum is exposed. Also
included are areas of Consumo clay and small areas of Hydraquents, saline
Humatas clay that has slopes of less than 40 percent.
Runoff is very rapid. The root zone is deep. This soil Hz--Hydraquents, saline. This map unit is in lagoon-
is very susceptible to erosion. Slippage is common on like areas and in depressions on river flood plains in
roadbanks and in ditches and drainageways. This soil the semiarid area. The areas generally are about 50
generally is not suitable for cultivation. A permanent to 100 acres in size.
vegetative cover needs to be maintained to control ero- These soils are saline. The water table is at or near
sion. Hillside ditches and diversions are very difficult the surface most of the year. These soils vary in color
to lay out, construct, and maintain because of the steep and texture throughout the profile. Organic material
slopes. Liming and fertilizing are difficult and costly, from decayed mangrove trees is scattered throughout
A large acreage is in shade-grown coffee. Other the profile, and other material, such as shells, coral,
areas are used as brush pasture and native pasture and marl, can also be found.
that has a low carrying capacity. Most of the coffee These soils have very severe limitations for cultiva-
farms have been abandoned and are in brush forest. tion because the water table and the content of harm-
This soil should be kept in permanent vegetation, ful salts are high. Reclamation is expensive. These
woodland, or pasture because of the steep slopes, rapid soils have been mainly in mangrove trees, and they
runoff, and the erosion hazard. Deferred grazing can are suitable as habitat for wildlife such as birds, oys-
be used in pastures. ters, and crabs.
Capability unit VIe-1; woodland suitability group These soils generally have very severe limitations
3cl. for nonfarm uses. Capability unit VIIIs-1; not in a
HxF-Humatas complex, 20 to 60 percent slopes, woodland suitability group.
This map unit is about 30 percent Humatas soil and
70 percent gravelly soils that are too variable to clas- Jacaguas series
sify. The soils in this complex are steep to very steep;
slopes are 20 to 60 percent. The surface layer is clay. The Jacaguas series consists of well drained, nearly
The Humatas soil is similar to the one described as level soils on flood plains in .the semiarid area very
representative of the series. The other soils, to a depth near streams, rivers, and drainageways. These soils
of more than 5 feet, are 70 to 80 percent red, yellow, formed in moderately fine textured over coarse tex-
and light gray, medium hard volcanic gravel; the tured sediment that washed from volcanic and lime-
gravel is angular and subangular in structure. These stone hills. Slopes are 0 to 2 percent. The annual rain-
soils are 20 to 30 percent reddish brown to red, very fall is 25 to 40 inches, and the temperature is 780 to
strongly acid, and slightly sticky and plastic clay. The 800 F.
soils in this complex are so intermingled that it was not In a representative profile, the surface layer is very







24 SOIL SURVEY

where the slope is less than 20 percent, areas of Con- practical to separate them in mapping at the scale
sumo clay, and a few areas of Daguey clay on hilltops, used.
Runoff is rapid. Erosion is a hazard. Slippage is Included in mapping are small areas where the soils
common on roadbanks and in ditches and drainage- have rocks and boulders on the surface.
ways. This soil is difficult to work because the slopes Most areas of this map unit are in abandoned coffee
are steep and the clay is sticky and plastic. Hillside trees and brush. A few areas are in shade-grown cof-
ditches and diversions are difficult to lay out, construct, fee and brushy pasture.
and maintain. The root zone is deep. Fertility is me- These soils have severe limitations for cultivated
dium, and crops respond well to heavy and periodical crops and for residential, commercial, industrial, or
applications of lime and fertilizer, recreational uses because of slope, rapid runoff, the
This soil has been used for shade-grown coffee, erosion hazard, and the large content of gravel. These
plantains, tanniers, yams, bananas, and oranges. Some soils are suitable for use as native pasture and wood-
areas have been used as native pasture. Other areas land and for wildlife food and cover.
are in improved pasture, and a large acreage is in Capability unit VIIe-1; woodland suitability group
brush. Most of the coffee farms have been abandoned 3cl.
and are brushy.
This soil can be planted periodically to all the crops Hydraqents
adapted to the humid uplands if erosion is controlled raquents
and large amounts of lime and fertilizer are applied. Hy--Hydraquents. This map unit is in lagoonlike
Pangolagrass and stargrass grow well on this soil. De- areas and in depressions on the flood plains of streams
ferred grazing can help to avoid overgrazing and con- and rivers. The areas generally are about 5 to 20 acres
troCal unit IVe-1; woodlanderosion in size. The water table is at or near the surface most
Capability unit IVe-1; woodland suitability group of the year.
2cl. The high water table severely limits these soils for
HmF2-Humatas clay, 40 to 60 percent slopes, cultivation. Artificial drainage is not feasible because
eroded. This is a very steep soil on side slopes and these soils do not have outlets for drainage. These
narrow ridges on humid uplands. The areas generally soils are best suited to wildlife food and cover.
are more than 200 acres in size. This soil is similar to These soils have severe limitations for residential
the one described as representative of the series, except commercial, industrial, or recreational uses.
it has a slightly thinner surface layer. Capability unit VIIIw-1; not in a woodland suitabil-
Included in mapping are a few areas that have rocks ity group.
and boulders on the surface and some severely eroded
soils on ridges where the substratum is exposed. Also
included are areas of Consumo clay and small areas of Hydraquents, saline
Humatas clay that has slopes of less than 40 percent.
Runoff is very rapid. The root zone is deep. This soil Hz--Hydraquents, saline. This map unit is in lagoon-
is very susceptible to erosion. Slippage is common on like areas and in depressions on river flood plains in
roadbanks and in ditches and drainageways. This soil the semiarid area. The areas generally are about 50
generally is not suitable for cultivation. A permanent to 100 acres in size.
vegetative cover needs to be maintained to control ero- These soils are saline. The water table is at or near
sion. Hillside ditches and diversions are very difficult the surface most of the year. These soils vary in color
to lay out, construct, and maintain because of the steep and texture throughout the profile. Organic material
slopes. Liming and fertilizing are difficult and costly, from decayed mangrove trees is scattered throughout
A large acreage is in shade-grown coffee. Other the profile, and other material, such as shells, coral,
areas are used as brush pasture and native pasture and marl, can also be found.
that has a low carrying capacity. Most of the coffee These soils have very severe limitations for cultiva-
farms have been abandoned and are in brush forest. tion because the water table and the content of harm-
This soil should be kept in permanent vegetation, ful salts are high. Reclamation is expensive. These
woodland, or pasture because of the steep slopes, rapid soils have been mainly in mangrove trees, and they
runoff, and the erosion hazard. Deferred grazing can are suitable as habitat for wildlife such as birds, oys-
be used in pastures. ters, and crabs.
Capability unit VIe-1; woodland suitability group These soils generally have very severe limitations
3cl. for nonfarm uses. Capability unit VIIIs-1; not in a
HxF-Humatas complex, 20 to 60 percent slopes, woodland suitability group.
This map unit is about 30 percent Humatas soil and
70 percent gravelly soils that are too variable to clas- Jacaguas series
sify. The soils in this complex are steep to very steep;
slopes are 20 to 60 percent. The surface layer is clay. The Jacaguas series consists of well drained, nearly
The Humatas soil is similar to the one described as level soils on flood plains in .the semiarid area very
representative of the series. The other soils, to a depth near streams, rivers, and drainageways. These soils
of more than 5 feet, are 70 to 80 percent red, yellow, formed in moderately fine textured over coarse tex-
and light gray, medium hard volcanic gravel; the tured sediment that washed from volcanic and lime-
gravel is angular and subangular in structure. These stone hills. Slopes are 0 to 2 percent. The annual rain-
soils are 20 to 30 percent reddish brown to red, very fall is 25 to 40 inches, and the temperature is 780 to
strongly acid, and slightly sticky and plastic clay. The 800 F.
soils in this complex are so intermingled that it was not In a representative profile, the surface layer is very







24 SOIL SURVEY

where the slope is less than 20 percent, areas of Con- practical to separate them in mapping at the scale
sumo clay, and a few areas of Daguey clay on hilltops, used.
Runoff is rapid. Erosion is a hazard. Slippage is Included in mapping are small areas where the soils
common on roadbanks and in ditches and drainage- have rocks and boulders on the surface.
ways. This soil is difficult to work because the slopes Most areas of this map unit are in abandoned coffee
are steep and the clay is sticky and plastic. Hillside trees and brush. A few areas are in shade-grown cof-
ditches and diversions are difficult to lay out, construct, fee and brushy pasture.
and maintain. The root zone is deep. Fertility is me- These soils have severe limitations for cultivated
dium, and crops respond well to heavy and periodical crops and for residential, commercial, industrial, or
applications of lime and fertilizer, recreational uses because of slope, rapid runoff, the
This soil has been used for shade-grown coffee, erosion hazard, and the large content of gravel. These
plantains, tanniers, yams, bananas, and oranges. Some soils are suitable for use as native pasture and wood-
areas have been used as native pasture. Other areas land and for wildlife food and cover.
are in improved pasture, and a large acreage is in Capability unit VIIe-1; woodland suitability group
brush. Most of the coffee farms have been abandoned 3cl.
and are brushy.
This soil can be planted periodically to all the crops Hydraqents
adapted to the humid uplands if erosion is controlled raquents
and large amounts of lime and fertilizer are applied. Hy--Hydraquents. This map unit is in lagoonlike
Pangolagrass and stargrass grow well on this soil. De- areas and in depressions on the flood plains of streams
ferred grazing can help to avoid overgrazing and con- and rivers. The areas generally are about 5 to 20 acres
troCal unit IVe-1; woodlanderosion in size. The water table is at or near the surface most
Capability unit IVe-1; woodland suitability group of the year.
2cl. The high water table severely limits these soils for
HmF2-Humatas clay, 40 to 60 percent slopes, cultivation. Artificial drainage is not feasible because
eroded. This is a very steep soil on side slopes and these soils do not have outlets for drainage. These
narrow ridges on humid uplands. The areas generally soils are best suited to wildlife food and cover.
are more than 200 acres in size. This soil is similar to These soils have severe limitations for residential
the one described as representative of the series, except commercial, industrial, or recreational uses.
it has a slightly thinner surface layer. Capability unit VIIIw-1; not in a woodland suitabil-
Included in mapping are a few areas that have rocks ity group.
and boulders on the surface and some severely eroded
soils on ridges where the substratum is exposed. Also
included are areas of Consumo clay and small areas of Hydraquents, saline
Humatas clay that has slopes of less than 40 percent.
Runoff is very rapid. The root zone is deep. This soil Hz--Hydraquents, saline. This map unit is in lagoon-
is very susceptible to erosion. Slippage is common on like areas and in depressions on river flood plains in
roadbanks and in ditches and drainageways. This soil the semiarid area. The areas generally are about 50
generally is not suitable for cultivation. A permanent to 100 acres in size.
vegetative cover needs to be maintained to control ero- These soils are saline. The water table is at or near
sion. Hillside ditches and diversions are very difficult the surface most of the year. These soils vary in color
to lay out, construct, and maintain because of the steep and texture throughout the profile. Organic material
slopes. Liming and fertilizing are difficult and costly, from decayed mangrove trees is scattered throughout
A large acreage is in shade-grown coffee. Other the profile, and other material, such as shells, coral,
areas are used as brush pasture and native pasture and marl, can also be found.
that has a low carrying capacity. Most of the coffee These soils have very severe limitations for cultiva-
farms have been abandoned and are in brush forest. tion because the water table and the content of harm-
This soil should be kept in permanent vegetation, ful salts are high. Reclamation is expensive. These
woodland, or pasture because of the steep slopes, rapid soils have been mainly in mangrove trees, and they
runoff, and the erosion hazard. Deferred grazing can are suitable as habitat for wildlife such as birds, oys-
be used in pastures. ters, and crabs.
Capability unit VIe-1; woodland suitability group These soils generally have very severe limitations
3cl. for nonfarm uses. Capability unit VIIIs-1; not in a
HxF-Humatas complex, 20 to 60 percent slopes, woodland suitability group.
This map unit is about 30 percent Humatas soil and
70 percent gravelly soils that are too variable to clas- Jacaguas series
sify. The soils in this complex are steep to very steep;
slopes are 20 to 60 percent. The surface layer is clay. The Jacaguas series consists of well drained, nearly
The Humatas soil is similar to the one described as level soils on flood plains in .the semiarid area very
representative of the series. The other soils, to a depth near streams, rivers, and drainageways. These soils
of more than 5 feet, are 70 to 80 percent red, yellow, formed in moderately fine textured over coarse tex-
and light gray, medium hard volcanic gravel; the tured sediment that washed from volcanic and lime-
gravel is angular and subangular in structure. These stone hills. Slopes are 0 to 2 percent. The annual rain-
soils are 20 to 30 percent reddish brown to red, very fall is 25 to 40 inches, and the temperature is 780 to
strongly acid, and slightly sticky and plastic clay. The 800 F.
soils in this complex are so intermingled that it was not In a representative profile, the surface layer is very







PONCE AREA OF SOUTHERN PUERTO RICO 25
dark grayish brown silty clay loam about 7 inches ter because permeability is rapid in the substratum.
thick. The subsoil is very dark grayish brown, firm Sprinkler irrigation can be used. Land leveling or
silty clay loam about 7 inches thick. The substratum, smoothing exposes coarse material at the surface.
between depths of 14 and 60 inches, is a mixture of Adapted species of grasses are few because rainfall is
fine sand, gravel, and cobbles, low. This soil can be easily worked with machinery.
Permeability is moderate in the surface layer and This soil has been planted to sugarcane and food
subsoil, and it is rapid in the substratum. The avail- crops, and a large acreage is in native pasture. If this
able water capacity is moderate in the surface layer soil is irrigated it is suited to sugarcane and to the
and subsoil. The root zone is restricted by the coarse vegetables and food crops commonly grown in the sur-
material in the substratum. Natural fertility is high. vey area.
These soils are easy to work. Runoff is slow, and these Capability units IIIs-1, irrigated, and IVc-4, non-
soils are not susceptible to erosion, irrigated; not in a woodland suitability group.
Jacaguas soils have been planted to sugarcane and
native pasture grasses for many years. Guineagrass, Jacana series
Angletongrass, and buffelgrass are the most common
grasses. If irrigated, these soils can be used for vege- The Jacana series consists of well drained, strongly
tables, sloping soils on foot slopes and low rolling hills in the
Representative profile of Jacaguas silty clay loam, semiarid area. These soils are moderately deep to vol-
1.9 kilometers west of kilometer marker 3.05 on High- canic rock. They formed in fine textured sediment and
way 510: fine textured residuum that was derived from basic
Ap-0 to 7 inches; very dark grayish brown volcanic rock. Slopes are 5 to 12 percent. The annual
(10YR 3/2) silty clay loam; moderate rainfall is 20 to 40 inches, and the temperature is 780
fine granular structure; firm, slightly to 800 F.
sticky and slightly plastic; many fine In a representative profile, the combined surface
roots; neutral; clear smooth boundary. layer and subsurface layer are very dark brown clay
B2-7 to 14 inches; very dark grayish brown about 13 inches thick. The subsoil is dark brown, very
(10YR 3/2) silty clay loam; weak fine firm clay about 14 inches thick. Highly weathered vol-
and medium subangular blocky structure canic rock that can be penetrated using a spade is at a
parting to granular; firm, slightly sticky depth of 27 inches.
and slightly plastic; many fine roots; Permeability is moderately slow, and the available
neutral; abrupt smooth boundary. water capacity is moderate. Natural fertility is high.
IIC-14 to 60 inches; mixture of fine sand, gravel, These soils are somewhat difficult to work. The content
and cobbles. of organic matter is high. Runoff is medium.
Thickness of the solum and depth to the coarse ma- Jacana soils have been in pasture for many years. In
trial in the substratum range from 12 to 20 inches. some areas they have been used for corn, tobacco, and
The Ap horizon has hue of 10YR and value and chroma pigeonpeas. The most common grasses are guineagrass,
of 2 and 3. The B2 horizon ranges from silty clay loam Angletongrass, and buffelgrass. The use of the soils for
to loam. Structure of the B2 horizon ranges from weak food crops and cut grasses is restricted because irriga-
fine to weak medium subangular blocky. The soil ma- tion water is not available.
trial is neutral throughout. Representative profile of Jacana clay, 5 to 12 per-
Jacaguas soils are on the same landscape as Cuyon, cent slopes, 12 meters east of kilometer marker 2.0 on
San Anton, Cortada, Machuelo, and Constancia soils. Highway 545:
Jacaguas soils have a thicker profile than Cuyon soils. Ap-0 to 7 inches; very dark brown (10YR 2/2)
Unlike San Anton and Cortada soils, Jacaguas soils clay; weak medium subangular blocky
have coarse material at a depth of 20 inches or less. parting to granular structure; firm,
Unlike Machuelo and Constancia soils, Jacaguas soils sticky and plastic; many fine roots; few
are noncalcareous, somewhat excessively drained, and fine and medium volcanic rock frag-
have coarse material at a depth of 20 inches or less. ments; mildly alkaline; clear smooth
Jg-Jacaguas silty clay loam. This is a nearly level boundary.
soil on alluvial fans and terraces along rivers and A12-7 to 13 inches; very dark brown (10YR
streams in the semiarid area. Slopes are 0 to 2 percent. 2/2) clay; weak coarse subangular
The areas of this soil generally are about 5 to 50 acres blocky structure; firm, sticky and plas-
in size. tic; many fine roots; pressure faces; few
Included in mapping are small areas of Cuyon loam fine volcanic rock fragments; mildly al-
and small areas that have a large number of rocks and kaline; clear wavy boundary.
boulders on the surface. Also included are a few areas B2-13 to 21 inches; dark brown (10YR 3/3)
of Riverwash. clay; weak coarse subangular blocky
Runoff is slow. This soil is not subject to erosion, structure; very firm, sticky and plastic;
If irrigated, this soil can be cropped intensively with- few fine roots; pressure faces; few fine
out loss of soil material. In some years it is subject to volcanic rock fragments; cracks to a
flooding from August to October. The root zone is deep, depth of 21 inches; mildly alkaline;
but it is restricted by the low available water capacity gradual wavy boundary.
of the substratum. This soil needs to be irrigated be- B3-21 to 27 inches; dark brown (10YR 3/3)
cause rainfall is low and poorly distributed throughout clay; weak coarse subangular blocky
the year. Furrows have poor stability; irrigation on structure; firm, sticky and plastic; few
furrows is difficult and requires a large amount of wa- fine roots; 30 percent, by volume, sapro-







26 SOIL SURVEY

lite; mildly alkaline; gradual wavy capacity is low. Natural fertility is medium. These
boundary. soils are easy to work. Runoff is medium to rapid, and
C-27 inches; weathered volcanic rock. these soils are highly susceptible to erosion.
The solum is 18 to 32 inches thick. Depth to the Juana Diaz soils have been in native pasture for
semiconsolidated rock is 20 to 40 inches. The Ap and many years. The most common grasses are guineagrass
A12 horizons have hue of 10YR and value and chroma and Angletongrass. A few acres are in brush.
of 2 and 3. The B2 horizon has hue of 10YR and Representative profile of Juana Diaz clay loam, 20
7.5YR, value of 3, and chroma of 3 or more. The B2 to 40 percent slopes, 24 meters south of kilometer
horizon is weak medium or weak coarse subangular marker 15.75 on Highway 14:
blocky in structure. The Ap horizon is mildly alkaline Ap-0 to 6 inches; 80 percent dark yellowish
to slightly acid. brown (10YR 3/4), 20 percent dark
Jacana soils are on the same landscape as Callabo, brown (10YR 4/3) clay loam; moderate
Juana Diaz, and Llanos soils. Jacana soils are finer fine and medium granular structure;
textured and deeper to rock than Callabo and Juana firm, slightly sticky and plastic; many
Diaz soils, and they are shallower than Llanos soils. fine roots; neutral; abrupt smooth
Jacana soils are underlain by semiconsolidated vol- boundary.
canic rock, unlike Llanos soils. B2-6 to 12 inches; dark yellowish brown (10YR
JnC-Jacana clay, 5 to 12 percent slopes. This is a 4/4) clay loam; weak medium and coarse
strongly sloping soil on foot slopes and low rolling hills subangular blocky structure; firm,
in the semiarid area. The areas of this soil generally slightly sticky and plastic; common fine
are about 20 to 50 acres in size. roots; neutral; clear smooth boundary.
Included in mapping are small areas where this soil B3-12 to 18 inches; yellowish brown (10YR 5/6)
has slopes of less than 5 percent. Also included are silt loam; weak medium subangular
some areas on hilltops where this soil has been inten- blocky structure; friable, slightly sticky
sively cultivated and is so eroded that material from and slightly plastic; few fine roots; 15
the substratum is included in the surface layer. percent, by volume, saprolite; mildly al-
Runoff is medium. If cultivated, this soil is subject kaline; clear smooth boundary.
to erosion. Cultivated crops can only be grown in the R-18 inches; semiconsolidated sandstone that is
wet months because rainfall is low and is poorly dis- easily penetrated using a spade.
tribute throughout the year. Furrow irrigation is dif- Thickness of the solum and depth to sandstone
ficult because of slope. Sprinkler irrigation can be used. ranges from 14 to 20 inches. The Ap horizon has hue
Land leveling or smoothing is difficult because of slope of 10YR and value and chroma of 3 and 4. The B2
and shallowness to rock. This soil is somewhat difficult horizon has hue of 10YR, value of 4 and 5, and chroma
to work because the clay is sticky. The root zone is of 4 and 6. The B2 horizon ranges from clay loam to
deep. Adapted species of grasses are few because rain- loam. The B2 horizon ranges from weak fine to coarse
fall is low. Erosion needs to be controlled if cultivated subangular blocky in structure.
crops are grown. If this soil is used as pasture, de- Juana Diaz soils are on the same landscape as Cal-
ferred grazing can help to avoid overgrazing. labo, Jacana, and Guanabano soils. Juana Diaz soils
In most areas, this soil has been used as native pas- are coarser textured than Callabo soils, are shallower
ture. The main grasses are Angletongrass and guinea- to rock and coarser textured than the Jacana soils, and
grass, and a few areas are in buffelgrass. Some areas are coarser textured and shallower to rock than Guana-
have been in corn, pigeonpeas, and pumpkins, and a bano soils. Unlike Guanabano soils, they are noncal-
very small acreage has been in sugarcane. These crops careous.
are grown during the rainy season. JzD-Juana Diaz clay loam, 12 to 20 percent slopes.
Capability units IIIe-3, irrigated, and IVc-1, non- This is a moderately steep soil on foot slopes, on the
irrigated; woodland suitability group 2dl. upper part of side slopes, and on hilltops on semiarid
uplands. The areas generally are about 20 to 50 acres
Juana Diaz series in size. This soil is similar to the one described as
representative of the series except it has a slightly
The Juana Diaz series consists of well drained, mod- thicker surface layer.
erately steep and steep soils on side slopes, foot slopes, Included in mapping are a few small areas of Callabo
and hilltops on semiarid uplands. These soils formed silty clay loam and areas where semiconsolidated sand-
in moderately fine textured and medium textured re- stone is at a depth of less than 14 inches.
siduum that was derived from sandstone. Slopes are Runoff is medium. Erosion is a hazard. This soil
12 to 40 percent. The annual rainfall is 25 to 40 inches, generally is not suitable for cultivation and should be
and the temperature is 780 to 800 F. maintained in permanent vegetation. Because rainfall
In a representative profile, the surface layer is dark is low and poorly distributed, only a few adapted
yellowish brown and dark brown clay loam about 6 species of grasses are suitable. The root zone is not
inches thick. The subsoil is about 12 inches thick. In the restricted by the semiconsolidated sandstone. This soil
upper 6 inches, it is dark yellowish brown, firm clay is easy to fill.
loam, and in the lower 6 inches it is yellowish brown, This soil has mainly been used as native pasture.
friable silt loam. Semiconsolidated sandstone that can Angletongrass and guineagrass are the main grasses.
be easily penetrated using a spade is at a depth of In some areas this soil is in brush and in a few areas
about 18 inches, it is in pigeonpeas. Because rainfall is low and because
Permeability is moderate, and the available water of slope and shallowness to sandstone, this soil is best







PONCE AREA OF SOUTHERN PUERTO RICO 27

suited to use as range. Deferred grazing helps to avoid dark brown (10YR 4/3); moderate fine
overgrazing and to control erosion. and medium granular structure; firm,
Capability unit VIe-4; woodland suitability group slightly sticky and plastic; many fine
3d1. roots; 15 percent fine and medium vol-
JzE-Juana Diaz clay loam, 20 to 40 percent slopes, canic rock fragments; few fine black
This is a steep soil on side slopes and hilltops on semi- concretions; strongly acid; clear smooth
arid uplands. The areas generally are about 20 to 100 boundary.
acres in size. This is the soil described as representa- B21t-10 to 15 inches; 60 percent strong brown
tive of the series. (7.5YR 5/6), 30 percent yellowish red
Included in mapping are a few small areas of Cal- (5YR 5/6), and 10 percent red (2.5YR
labo silty clay loam and a few areas, especially on hill- 4/8) clay, rubbed color yellowish red
tops, where the soils are severely eroded. (5YR 5/6); moderate medium subangu-
Runoff is rapid. Erosion is a hazard. This soil is not lar blocky structure; firm, slightly sticky
suited to cultivation and should be maintained in and plastic; thin discontinuous clay
permanent vegetation to control erosion. Rainfall is films; few fine roots; few fine black con-
low and poorly distributed throughout the year. There cretions; black stains because of root
are few adapted species of grasses. The root zone is not decay; strongly acid; clear smooth
restricted by the semiconsolidated sandstone. The plow boundary.
layer is easy to till. B22t-15 to 23 inches; 70 percent strong brown
This soil has been mostly in native pasture grasses, (7.5YR 5/8), 20 percent yellowish red
mainly guineagrass and Angletongrass. A few areas (5YR 4/6), and 10 percent red (2.5YR
are in pigeonpeas, and some areas are in brush. Be- 4/8) clay, rubbed color strong brown
cause of low rainfall, the erosion hazard, and shallow- (7.5YR 5/6); weak medium subangular
ness to the semiconsolidated sandstone, this soil is best blocky structure; firm, slightly sticky
suited to use as range. A controlled stocking rate helps and plastic; thin discontinuous clay
to avoid overgrazing, films; few fine roots; few fine black con-
Capability unit VIIe-3; woodland suitability group cretions; black stains because of root
3d1. decay; strongly acid; clear smooth
boundary.
Lares series B23t-23 to 33 inches; 85 percent strong brown
(7.5YR 5/6), 10 percent yellowish red
The Lares series consists of moderately well drained, (5YR 6/6), and 5 percent mottles of
strongly sloping soils. These soils are on terraces be- light gray (10YR 7/1) clay, rubbed color
low the red and brown soils on the humid uplands. strong brown (7.5YR 5/8); weak me-
They formed in fine textured material. The slope dium subangular blocky structure; firm,
ranges from 5 to 12 percent. The annual rainfall slightly sticky and plastic; thin patchy
ranges from 60 to 70 inches, and the temperature clay films; few fine roots; few fine black
ranges from 760 to 780 F. concretions; black stains because of root
In a representative profile, the surface layer is dark decay; strongly acid; gradual wavy
brown and dark yellowish brown clay about 10 inches boundary.
thick. The subsoil is about 30 inches thick. In the upper B3-33 to 40 inches; 80 percent dark brown
13 inches, it is strong brown, yellowish red, and red, (7.5YR 4/4), 10 percent strong brown
firm clay; in the 10 inches below that, it is strong (7.5YR 5/6), and 10 percent light gray
brown and yellowish red firm clay that has light gray (10YR 7/1) clay, rubbed color brown
mottles; and in the lower 7 inches, it is dark brown, (7.5YR 5/4); weak medium subangular
strong brown, and light gray, firm clay. The substra- blocky structure; firm, slightly sticky
tum, between depths of 40 and 60 inches, is strong and plastic; few patchy clay films; few
brown, firm clay. fine black concretions; strongly acid;
Lares soils are moderately permeable. They have gradual wavy boundary.
moderate available water capacity and medium natural C-40 to 60 inches; rubbed color strong brown
fertility and are somewhat difficult to work. Crops (7.5YR 5/8) clay; massive; firm,
respond well to fertilizer. The content of organic mat- slightly sticky and plastic; strongly acid.
ter is moderate, and runoff is medium. The solum is 30 to 50 inches thick. The B2t horizon
Lares soils have been planted to a large variety of is 18 to 30 inches thick. The Ap horizon has hue of
food crops for many years. In some areas they are 10YR and 7.5YR, value of 3 and 4, and chroma of 3
planted to sugarcane and pasture grasses. Plantains, and higher. The B2t horizon is weak to moderate and
yams, and tanniers are among the food crops grown, fine to medium subangular blocky in structure. It has
Pangolagrass, stargrass, and guineagrass are among clay films that are thin patchy to thin discontinuous.
the grasses that grow well on these soils. Lares soils are on the same landscape as Daguey,
Representative profile of Lares clay, 5 to 12 percent Humatas, and Mucara soils. Unlike Daguey and Hu-
slopes, 200 meters east of kilometer marker 0.6 on matas soils, Lares soils are moderately well drained.
Highway 514: Lares soils have a thicker profile and are redder and
Ap-- to 10 inches; 80 percent dark brown more acid than Mucara soils.
(10YR 3/3), 20 percent dark yellowish LeC-Lares clay, 5 to 12 percent slopes. This is a
brown (10YR 4/4) clay, rubbed color strongly sloping soil on terraces and foot slopes below







28 SOIL SURVEY

the red and brown soils of the humid uplands. It gen- tic; many fine roots; many patchy clay
erally is in areas of about 20 to 50 acres. films; many fine quartz grains; very
Included in mapping are small areas of soils that strongly acid; clear smooth boundary.
have stones and boulders on the surface and a few B22t-12 to 19 inches; red (2.5YR 4/6) clay;
areas where the slope is less than 5 percent. moderate fine and medium subangular
Runoff is medium. Erosion is a hazard. Some meas- blocky structure; firm, slightly sticky
ures for controlling erosion are needed if cultivated and plastic; common fine roots; com-
crops are grown. This soil has a plow layer that is mon patchy clay films; many fine quartz
difficult to work because of the high clay content and grains; very strongly acid; clear smooth
stickiness and plasticity. This soil should be tilled at boundary.
the optimum moisture content to prevent large clods B3-19 to 28 inches; red (2.5YR 4/8) silty clay;
from forming. The root zone is deep. Fertility is me- weak fine and medium subangular blocky
dium, and crops respond well to heavy applications of structure; firm, slightly sticky and plas-
fertilizers. The use of machinery is feasible. tic; few fine roots; few fine thin patchy
This soil has been used mainly for sugarcane. In clay films; 25 percent of horizon is sapro-
some areas it is in native pasture and food crops. This lite; many fine quartz grains; very
soil has some limitations, but it can be used safely for strongly acid; gradual wavy boundary.
clean cultivation if some management practices are C-28 to 60 inches; variegated colors of the sap-
used to control erosion. It is suited to all crops com- rolite of red, strong brown, and reddish
only grown in the area such as plantains, yams, tan- brown clay loam; massive; friable,
niers, and coffee. Pangolagrass and stargrass grow slightly sticky and slightly plastic; many
well on this soil. Merkergrass can be grown for green fine quartz grains; very strongly acid.
chop. The solum is 20 to 32 inches thick. The B2t horizon
Capability unit IIIe-1; woodland suitability group is 16 to 26 inches thick. The Ap horizon has hue of
2c2. 7.5YR and 5YR, value of 4, and chroma of 3 and 4.
The B2t horizon has hue of 5YR and 2.5YR, value of
Lirios series 4, and chroma of 4 to 8. The B21t horizon is clay to
silty clay. The C horizon is clay loam to silty clay loam.
The Lirios series consists of well drained, very steep Lirios soils are on the same landscape as Pellejas
soils on side slopes and narrow hilltops on the strongly soils. They have a thicker B horizon and are redder
dissected, humid uplands. These soils formed in fine and finer textured than Pellejas soils.
textured and moderately fine textured residuum that LmF2-Lirios clay loam, 40 to 60 percent slopes,
weathered from plutonic rocks. The slope ranges from eroded. This is a very steep soil on side slopes and
40 to 60 percent. The annual rainfall ranges from 80 narrow ridges on the humid uplands. It generally is in
to 90 inches, and the temperature ranges from 770 to areas of about 50 to 100 acres.
800 F. Included in mapping are areas of Humatas and Con-
In a representative profile, the surface layer is dark sumo clay and a few small areas of Pellajas clay loam.
reddish brown clay loam about 5 inches thick. The sub- Also included are a few areas where this soil has slopes
soil is about 23 inches thick. In the upper 14 inches, of less than 40 percent.
it is red, firm clay, and in the lower 9 inches, it is red, Runoff is very rapid. Erosion is a hazard if this soil
firm silty clay. The substratum, between depths of 28 is not properly managed. Deep gullies are common in
and 60 inches, is clay loam that has variegated colors drainageways. Slips are common on roadbanks and
of red, strong brown, and reddish brown. in ditches and drainageways. Diversion ditches are dif-
These soils are moderately permeable. They have ficult to lay out, construct, and maintain. Liming and
moderate available water capacity and medium nat- fertilizing are difficult and costly. The root zone is
ural fertility, and they are easy to work. Runoff is very deep. Fertility is medium.
rapid, and the soils are highly susceptible to erosion. This soil has been mainly in native pasture, shade-
Crops respond well to fertilizer, grown coffee, bananas, oranges, and pangolagrass. In
Lirios soils have been used for shade-grown coffee some areas it is in brushy woods. Because of steepness
and as native pasture. Small areas were planted to of slope and the hazard of erosion, this soil has very
sugarcane. Pangolagrass, guineagrass, and stargrass severe limitations for cultivated crops. It should be
grow well on these soils, maintained in permanent vegetation such as trees or
Representative profile of Lirios clay loam, 40 to 60 pasture grasses. Pastures should have a controlled
percent slopes, eroded, 1.5 kilometers north of kilome- stocking rate to avoid overgrazing.
ter marker 3.8 on Highway 524: Capability unit VIIe-1; woodland suitability group
Ap-0 to 5 inches; dark reddish brown (5YR 3cl.
3/4) clay loam; moderate fine granular
structure; firm, slightly sticky and plas- Llanos series
tic; many fine roots; many fine quartz
grains; very strongly acid; clear smooth The Llanos series consists' of well drained, gently
boundary. sloping to strongly sloping soils on foot slopes, alluvial
B21t-5 to 12 inches; red (2.5YR 4/6) clay with fans, and stream terraces in the semiarid area. These
coatings of reddish brown (2.5YR 4/4) soils formed in fine textured and moderately fine tex-
moderate medium subangular blocky tured sediment that derived from basic volcanic rock.
structure; firm, slightly sticky and plas- The slope ranges from 2 to 12 percent. The annual







28 SOIL SURVEY

the red and brown soils of the humid uplands. It gen- tic; many fine roots; many patchy clay
erally is in areas of about 20 to 50 acres. films; many fine quartz grains; very
Included in mapping are small areas of soils that strongly acid; clear smooth boundary.
have stones and boulders on the surface and a few B22t-12 to 19 inches; red (2.5YR 4/6) clay;
areas where the slope is less than 5 percent. moderate fine and medium subangular
Runoff is medium. Erosion is a hazard. Some meas- blocky structure; firm, slightly sticky
ures for controlling erosion are needed if cultivated and plastic; common fine roots; com-
crops are grown. This soil has a plow layer that is mon patchy clay films; many fine quartz
difficult to work because of the high clay content and grains; very strongly acid; clear smooth
stickiness and plasticity. This soil should be tilled at boundary.
the optimum moisture content to prevent large clods B3-19 to 28 inches; red (2.5YR 4/8) silty clay;
from forming. The root zone is deep. Fertility is me- weak fine and medium subangular blocky
dium, and crops respond well to heavy applications of structure; firm, slightly sticky and plas-
fertilizers. The use of machinery is feasible. tic; few fine roots; few fine thin patchy
This soil has been used mainly for sugarcane. In clay films; 25 percent of horizon is sapro-
some areas it is in native pasture and food crops. This lite; many fine quartz grains; very
soil has some limitations, but it can be used safely for strongly acid; gradual wavy boundary.
clean cultivation if some management practices are C-28 to 60 inches; variegated colors of the sap-
used to control erosion. It is suited to all crops com- rolite of red, strong brown, and reddish
only grown in the area such as plantains, yams, tan- brown clay loam; massive; friable,
niers, and coffee. Pangolagrass and stargrass grow slightly sticky and slightly plastic; many
well on this soil. Merkergrass can be grown for green fine quartz grains; very strongly acid.
chop. The solum is 20 to 32 inches thick. The B2t horizon
Capability unit IIIe-1; woodland suitability group is 16 to 26 inches thick. The Ap horizon has hue of
2c2. 7.5YR and 5YR, value of 4, and chroma of 3 and 4.
The B2t horizon has hue of 5YR and 2.5YR, value of
Lirios series 4, and chroma of 4 to 8. The B21t horizon is clay to
silty clay. The C horizon is clay loam to silty clay loam.
The Lirios series consists of well drained, very steep Lirios soils are on the same landscape as Pellejas
soils on side slopes and narrow hilltops on the strongly soils. They have a thicker B horizon and are redder
dissected, humid uplands. These soils formed in fine and finer textured than Pellejas soils.
textured and moderately fine textured residuum that LmF2-Lirios clay loam, 40 to 60 percent slopes,
weathered from plutonic rocks. The slope ranges from eroded. This is a very steep soil on side slopes and
40 to 60 percent. The annual rainfall ranges from 80 narrow ridges on the humid uplands. It generally is in
to 90 inches, and the temperature ranges from 770 to areas of about 50 to 100 acres.
800 F. Included in mapping are areas of Humatas and Con-
In a representative profile, the surface layer is dark sumo clay and a few small areas of Pellajas clay loam.
reddish brown clay loam about 5 inches thick. The sub- Also included are a few areas where this soil has slopes
soil is about 23 inches thick. In the upper 14 inches, of less than 40 percent.
it is red, firm clay, and in the lower 9 inches, it is red, Runoff is very rapid. Erosion is a hazard if this soil
firm silty clay. The substratum, between depths of 28 is not properly managed. Deep gullies are common in
and 60 inches, is clay loam that has variegated colors drainageways. Slips are common on roadbanks and
of red, strong brown, and reddish brown. in ditches and drainageways. Diversion ditches are dif-
These soils are moderately permeable. They have ficult to lay out, construct, and maintain. Liming and
moderate available water capacity and medium nat- fertilizing are difficult and costly. The root zone is
ural fertility, and they are easy to work. Runoff is very deep. Fertility is medium.
rapid, and the soils are highly susceptible to erosion. This soil has been mainly in native pasture, shade-
Crops respond well to fertilizer, grown coffee, bananas, oranges, and pangolagrass. In
Lirios soils have been used for shade-grown coffee some areas it is in brushy woods. Because of steepness
and as native pasture. Small areas were planted to of slope and the hazard of erosion, this soil has very
sugarcane. Pangolagrass, guineagrass, and stargrass severe limitations for cultivated crops. It should be
grow well on these soils, maintained in permanent vegetation such as trees or
Representative profile of Lirios clay loam, 40 to 60 pasture grasses. Pastures should have a controlled
percent slopes, eroded, 1.5 kilometers north of kilome- stocking rate to avoid overgrazing.
ter marker 3.8 on Highway 524: Capability unit VIIe-1; woodland suitability group
Ap-0 to 5 inches; dark reddish brown (5YR 3cl.
3/4) clay loam; moderate fine granular
structure; firm, slightly sticky and plas- Llanos series
tic; many fine roots; many fine quartz
grains; very strongly acid; clear smooth The Llanos series consists' of well drained, gently
boundary. sloping to strongly sloping soils on foot slopes, alluvial
B21t-5 to 12 inches; red (2.5YR 4/6) clay with fans, and stream terraces in the semiarid area. These
coatings of reddish brown (2.5YR 4/4) soils formed in fine textured and moderately fine tex-
moderate medium subangular blocky tured sediment that derived from basic volcanic rock.
structure; firm, slightly sticky and plas- The slope ranges from 2 to 12 percent. The annual







PONCE AREA OF SOUTHERN PUERTO RICO 29
rainfall ranges from 25 to 45 inches, and the tempera- volume, fine pebbles; mildly alkaline;
ture ranges from 780 to 800 F. gradual wavy boundary.
In a representative profile, the surface layer is very IIC3-50 to 60 inches; dark brown (10YR 4/3)
dark brown clay about 5 inches thick. The subsurface sandy loam; single grained; friable;
layer is black clay about 5 inches thick. The subsoil is nonsticky and nonplastic; mildly alka-
19 inches thick. In the upper 5 inches, it is very dark line.
brown and black firm clay; and in the lower 14 inches, The solum is 23 to 36 inches thick. The A horizon
it is dark brown, firm clay. The substratum, between has hue of 10YR, value of 2 and 3, and chroma of 1 to
depths of 29 and 38 inches, is dark brown, firm clay 3. The upper part of the C horizon ranges from clay
loam; between depths of 38 and 50 inches, it is dark loam to sandy clay loam; the lower part of the C hori-
brown, friable sandy clay loam; between depths of 50 zon ranges from sandy loam to loamy sand.
and 60 inches it is dark brown, friable sandy loam. Llanos soils are on the same landscape as Jacana and
Llanos soils have moderately slow permeability. The Callabo soils. They have a thicker profile than Jacana
substratum is more permeable than the other layers. and Callabo soils, and they do not have the semi-
These soils have a high available water capacity and consolidated rock that Jacana and Callabo soils have.
high natural fertility, and they are difficult to work. LnB-Llanos clay, 2 to 5 percent slopes. This is a
The content of organic matter is high, and runoff is gently sloping soil on foot slopes, alluvial fans, and
slow to medium, terraces in the semiarid area. It generally is in areas of
Most of these soils have been in pasture for many about 50 to 100 acres. This soil is similar to the one
years. Guineagrass, Angletongrass, and buffelgrass are described as representative of the series, except it has a
the best adapted grasses. Small areas have been planted slightly thicker surface layer.
to sorghum for silage. If irrigated, the Llanos soils can Included in mapping are areas of Jacana clay, small
be used for many food crops. areas of narrow strips along drainageways where the
Representative profile of Llanos clay, 5 to 12 percent slope is slightly more than 5 percent, and some small
slopes, eroded, 250 meters south of kilometer marker areas of soils that have calcareous material at a depth
15.8 on Highway 150: below 2 feet.
All-0 to 5 inches; very dark brown (10YR 2/2) Runoff is slow, but in heavy rains erosion is a hazard
clay; moderate fine and medium granu- if the soil is cultivated. This soil can be used safely for
lar structure; firm, slightly sticky and cultivated crops, but some measures for controlling
plastic; many fine roots; neutral; clear erosion are needed. Heavy showers are common in
smooth boundary. favorable years. Because of the low and poorly dis-
A12-5 to 10 inches; black (10YR 2/1) tribute rainfall, food crops are restricted to the rainy
clay; weak medium subangular blocky season. Long drought periods are common.
structure; firm, slightly sticky and plas- This soil has a plow layer that is difficult to work
tic; many fine roots; neutral; clear because of stickiness and plasticity. This soil should be
smooth boundary, tilled at the optimum moisture content to help prevent
Bl-10 to 15 inches; very dark brown (10YR large clods. Land leveling or smoothing is difficult be-
2/2) and black (10YR 2/1) clay; weak cause of the poor workability of the soil. The root zone
coarse subangular blocky structure; very is deep. This soil has only a few adapted kinds of
firm, sticky and plastic; few fine roots; grasses because of low rainfall. The use of machinery
many pressure faces; 10 percent, by vol- is feasible. This soil is fertile, and crops respond well
ume, fine and very fine volcanic rock to fertilizer.
fragments; neutral; clear smooth bound- Because there is no irrigation, most of the acreage
ary. of this soil has been in pasture grasses, mainly Angle-
B2-15 to 23 inches; dark brown (10YR 4/3) tongrass and guineagrass. Some small areas are in
clay; moderate coarse subangular blocky buffelgrass. Crops such as corn, pumpkins, and pigeon-
structure; very firm, sticky and plastic; peas are grown in the rainy season. Scarcity of irriga-
few fine roots; many pressure faces; 5 tion water is a limitation on this soil. If irrigated,
percent, by volume, very fine volcanic this soil is suited to sugarcane. Merker and sorghum
rock fragments; neutral; clear wavy grasses can be grown as green chop in irrigated areas.
boundary. Capability units IIs-3, irrigated, and IIIc-1, non-
B3-23 to 29 inches; dark brown (10YR 4/3) irrigated; not in a woodland suitability group.
clay; weak medium subangular blocky LnC2-Llanos clay, 5 to 12 percent slopes, eroded.
structure; firm, slightly sticky and plas- This is a strongly sloping soil mainly on foot slopes and
tic; few fine roots; 10 percent, by volume, stream terraces in the semiarid area. It generally is in
fine pebbles; neutral; cracks to a depth areas of about 50 to 100 acres. This is the soil described
of 29 inches; clear wavy boundary. as representative of the series. Gullies are common.
C1-29 to 38 inches; dark brown (10YR 4/3) clay Included in mapping are a few small areas of soils
loam; massive; firm, slightly sticky and that are calcareous at a depth below 24 inches. Also in-
plastic; 10 percent, by volume, fine peb- cluded are some small areas of soils that are close to
bles; mildly alkaline; gradual wavy gullies where the underlying coarse material is closer
boundary. to the surface.
C2-38 to 50 inches; dark brown (10YR 4/3) Runoff is medium. Erosion is a hazard. If this soil
sandy clay loam; massive; friable, non- is used for cultivated crops, some measures will be
sticky and slightly plastic; 10 percent, by needed to control erosion, especially in gullies. Heavy







30 SOIL SURVEY

showers are common in favorable years. Long drought slightly sticky and plastic; discontinuous
periods are common. Food crops are mainly grown in clay films; many fine roots; very strongly
the rainy season, acid; clear smooth boundary.
The plow layer is difficult to work because the clay B22t-13 to 20 inches, 65 percent yellowish red
is sticky and plastic. Land leveling or smoothing is not (5YR 4/8), 20 percent yellowish brown
recommended because of the poor workability of the (10YR 5/8), and 15 percent red (2.5YR
soil and strong slopes. The root zone is deep. Because 4/6) clay, yellowish red (5YR 5/6)
of low, poorly distributed rainfall, food crops are rubbed; strong medium subangular
grown only in the rainy season. The use of machinery blocky structure; firm, slightly sticky
is feasible. This soil is fertile, and crops respond well and plastic; common fine roots; discon-
to fertilizer, tinuous clay films; very strongly acid;
In most areas this soil has been in pasture grasses, clear smooth boundary.
mainly guineagrass and Angletongrass. A few areas B23t-20 to 30 inches, 70 percent red (2.5YR
are in buffelgrass. Food crops such as corn, pumpkins, 4/6), 20 percent yellowish brown (10YR
and pigeonpeas grow well during the rainy season. 5/8), and 10 percent red (2.5YR 4/8)
Lack of water for irrigation is a limitation on this soil. clay, red (2.5YR 5/8) rubbed; moderate,
Furrow irrigation is not practical because of the slope, fine and medium, subangular blocky
Sprinkler irrigation is practical. If irrigated, this soil structure; firm, slightly sticky and plas-
is suited to sugarcane and a wide variety of food crops. tic; few fine roots; discontinuous clay
Merkergrass and sorghum can be grown as green chop films; very strongly acid; gradual wavy
in irrigated areas. boundary.
Capability units IIIe-5, irrigated, and IVc-1, non- B31-30 to 39 inches, 80 percent yellowish red
irrigated; not in a woodland suitability group. (5YR 4/6), 10 percent yellowish brown
(10YR 5/8), and 10 percent red (2.5YR
Los Guineos series 5/8) clay, yellowish red (5YR 5/8)
rubbed; weak medium subangular
The Los Guineos series consists of deep, moderately blocky structure; firm, slightly sticky
well drained soils that are steep and very steep and and plastic; 20 percent of horizon is
have slopes of 20 to 60 percent. These soils formed in saprolite; very strongly acid; gradual
fine-textured residuum derived from basic volcanic wavy boundary.
rocks. They are on side slopes and hilltops in areas of B32-39 to 48 inches, 60 percent yellowish red
high altitude and high rainfall. The average annual (5YR 4/8), 20 percent red (2.5YR 5/8),
soil temperature at a depth of 20 inches is below 720 F. and 20 percent yellowish brown (10YR
The annual rainfall ranges from 90 to 100 inches, and 5/8) clay; weak, fine and medium, sub-
the temperature ranges from 690 to 720 F. angular blocky structure; firm, slightly
In a representative profile, the surface layer is dark sticky and plastic; few patchy clay films;
yellowish brown and yellowish brown clay about 7 40 percent of horizon is saprolite; very
inches thick. The subsoil is about 41 inches thick. In strongly acid; gradual wavy boundary.
the upper 6 inches it is yellowish brown firm clay, and C-48 to 72 inches, red (2.5YR 4/6 and 4/8),
in the lower 35 inches it is mainly yellowish red, yel- yellowish brown (10YR 5/8), and yel-
lowish brown, and red firm clay. The substratum is lowish red (5YR 4/8) clay saprolite;
red, yellowish brown, and yellowish red friable clay massive; friable, slightly sticky and
that extends to a depth of 72 inches. slightly plastic; very strongly acid.
The Los Guineos soils are moderately permeable. The solum ranges from 38 to 56 inches in thickness.
They have moderate to high available water capacity The Ap horizon has hue of 10YR or 7.5YR, value of
and low natural fertility and are difficult to work. Sur- 4 or 5, and chroma of 4 or higher. The B2t horizon
face runoff is rapid to very rapid, ranges in structure from moderate to strong and fine
These soils have been used for food crops such as to coarse, subangular blocky. The B3 horizon is 20 to
yams, plantains, and tanniers. Some areas are in shade- 50 percent saprolite.
grown coffee trees and brush, and others are in native The Los Guineos soils are on the same landscape as
pasture. the Maricao soils. They have a thicker profile and are
Representative profile of Los Guineos clay, 20 to 40 deeper to saprolite than the Maricao soils.
percent slopes, 50 meters east of kilometer marker LuE-Los Guineos clay, 20 to 40 percent slopes. This
5.1 on Highway 522: soil is on side slopes and ridges in the humid uplands,
Ap-0 to 7 inches, 60 percent dark yellowish generally in areas of about 100 to 500 acres. It has the
brown (10YR 4/4) and 40 percent yel- profile described as representative of the series.
lowish brown (10YR 5/8) clay; moder- Included with this soil in mapping are some rounded
ate medium granular structure; firm, hilltops and narrow foot slopes where slopes are less
slightly sticky and plastic; many fine than 20 percent and some narrow areas along drain-
roots; few worm casts; rust due to root ageways where slopes are more than 40 percent.
decay; very strongly acid; clear smooth Runoff is rapid on this soil, and some measures for
boundary. controlling erosion are needed if cultivated crops are
B21t-7 to 13 inches, yellowish brown (10YR grown. The root zone is deep, but the plow layer is
5/8) clay; strong, medium and coarse, difficult to work because of the sticky and plastic clay.
subangular blocky structure; firm, Ditches are difficult to lay out, establish, and maintain







PONCE AREA OF SOUTHERN PUERTO RICO 31
because of the steep slopes. Slippage is common in road soils occur in such an intricate pattern that it was not
cuts, ditches, and drainageways. practical to separate them at the scale used in map-
Because of the steep slopes, the hazard of erosion, ping. Los Guineos and Maricao soils each make up
high altitude, and high rainfall, this soil has severe about 40 percent of the association, and the remaining
limitations for cultivated crops. Its use is limited 20 percent consists of Stony rock land and patches of
largely to pasture and forest, but because of the high soils that are not classified. The soils are clayey
altitude and high rainfall, few species of trees suitable throughout.
for commercial purposes can be grown. Included in mapping are some high peaks where
This soil has mainly been in native pasture of low slopes are more than 60 percent.
carrying capacity. Some areas are in shade-grown cof- Because of the slope, rapid runoff, the hazard of
fee trees, and a large acreage is in brush. Very few erosion, and the presence of rocks and boulders, the
acres are in food crops. soils of this map unit generally are not suitable for
Capability unit VIe-1; woodland suitability group cultivation. They are better suited to forest and wild-
2c1. life food and cover than to most other uses. Clearing
LuF-Los Guineos clay, 40 to 60 percent slopes. This these soils for pasture is very difficult and costly. These
is a very steep soil on side slopes and narrow ridges soils have severe limitations for nonfarm uses in gen-
in the humid uplands. It generally is in areas of more eral.
than 500 acres. Most of the acreage of this map unit is in brush.
Included with this soil in mapping are some hilltops Very few areas are in brushy pasture.
that have a large amount of rocks and boulders on the Capability unit VIIs-5; woodland suitability group
surface and some ridgetops where slopes are more than 3x2.
60 percent.
Runoff is very rapid on this soil, and erosion is a Machuelo series
hazard. The root zone is deep, but the soil is difficult to
work because of the slope and the stickiness and plas- The Machuelo series consists of poorly drained, cal-
ticity of the clay. The use of lime and fertilizer is not careous, nearly level soils in the lower lying flood plains
practical. Ditches are very difficult to lay out, estab- in the semiarid area. These soils formed in fine tex-
lish, and maintain, and slippage is very common in tured sediment that weathered from volcanic and lime-
road cuts and drainageways. stone rocks. The slope ranges from 0 to 2 percent. The
Because of the slope, the hazard of erosion, high annual rainfall ranges from 25 to 40 inches, and the
altitude, and high rainfall, this soil has very severe temperature ranges from 780 to 800 F.
limitations for cultivated crops. Because of the high In a representative profile, the surface layer is dark
altitude and high rainfall, only a few species of trees grayish brown, mottled clay about 8 inches thick. The
suitable for commercial purposes can be grown. This substratum, to a depth of 21 inches, is mottled, dark
soil should be maintained in permanent vegetation. gray, firm clay; between depths of 21 and 29 inches it
A large acreage of this soil is in brush, and some is mottled, greenish gray, firm clay; between depths of
areas are in brushy pasture of low carrying capacity. 29 and 37 inches it is light olive brown, greenish gray,
Capability unit VIIe-1; woodland suitability group and dark bluish gray, firm clay; and between depths of
2c3. 37 and 60 inches it is olive, dark greenish gray, gray,
LyFX-Los Guineos-Maricao association, steep. This and light olive brown clay.
map unit is on side slopes and ridges in the humid Machuelo soils are slowly permeable. They have a
uplands. Slopes are 20 to 60 percent. The soils occur in high available water capacity and high natural fer-
such an intricate pattern that it was not practical to utility. They are difficult to work. Runoff is slow. These
separate them at the scale used in mapping. Los soils have a restricted root zone because of a fluctuating
Guineos soils make up about 60 percent of the associa- water table.
tion, and Maricao soils make up about 40 percent. If irrigated, Machuelo soils are suited to sugarcane.
These soils are clayey throughout. Many acres are planted to this crop. Areas where wa-
Included with this association in mapping are some ter for irrigation is not available are in native pasture
areas where slopes are more than 60 percent and a grasses, mostly Angletongrass.
few areas that have stones and boulders on the surface. Representative profile of Machuelo clay, 2.5 kilo-
Because of slope, rapid runoff, and the hazard of meters south of kilometer marker 123.75 on High-
erosion, the soils of this map unit generally are not way 1:
suitable for cultivation. They are better suited to forest Ap-0 to 8 inches; dark grayish brown (10YR
and wildlife food and cover than to most other uses. 4/2) clay; few fine distinct yellowish
Clearing the soils for pasture is very difficult and brown (10YR 5/6), strong brown
costly. These soils have severe limitations for nonfarm (7.5YR 5/8), and gray (10YR 6/1) mot-
uses in general. tles; moderate fine and medium granu-
Most of the acreage of this map unit is in hardwood lar structure; firm, slightly sticky and
trees, sierra palms, and tree ferns. Very few areas are plastic; many fine roots; common fine
in brushy pasture. volcanic rock fragments; strong effer-
Capability unit VIIe-1; woodland suitability group vescence; abrupt smooth boundary.
2c3. Clg-8 to 16 inches; dark gray (10YR 4/1) clay;
LzFX-Los Guineos-Maricao-Stony rock land associa- few fine distinct light gray (10YR 7/1)
tion, steep. This map unit is on side slopes and ridges and few fine distinct yellowish brown
in the humid uplands. Slopes are 30 to 60 percent. The (10YR 5/6) mottles; weak medium and








32 SOIL SURVEY
coarse subangular blocky structure; little or no vegetation and a few areas of somewhat
firm, slightly sticky and plastic; many poorly drained Constancia silty clay.
fine roots; common fine volcanic rock Runoff is slow. This soil is not subject to erosion. If
fragments; common fine limestone frag- properly drained and irrigated, it can be intensively
ments; few shell fragments; strong ef- cropped without loss of soil material. It is subject to
fervescence; abrupt smooth boundary, flooding in some years, generally from August to Octo-
C2g-16 to 21 inches; dark gray (5Y 4/1) clay; ber. Because permeability is slow, this soil can become
common fine distinct olive yellow (2.5Y saturated during heavy rains. Long drought periods
6/6), a few fine faint gray (5Y 5/1), are common.
and a few fine distinct dark grayish Workability is poor. Land leveling and smoothing
brown (10YR 4/2) mottles; weak me- are difficult due to a high clay content, stickiness, and
dium subangular blocky structure; firm, plasticity. Machinery can only be used in the dry
slightly sticky and plastic; common fine months. Earth movement should be done at optimum
roots; common fine volcanic rock frag- moisture content. The root zone is restricted by a high
ments; few fine limestone fragments; water table. This soil is fertile, and crops respond well
strong effervescence; clear smooth to fertilizer.
boundary. Most of the acreage has been in sugarcane for many
C3g-21 to 29 inches; greenish gray (5GY 5/1) years. If properly managed, this soil is suitable for
clay; many fine prominent yellowish sugarcane and rice.
brown (10YR 5/4), common fine promi- Capability units IIIw-1, irrigated, and IVc-2, non-
nent olive yellow (2.5Y 6/6), few fine irrigated; not in a woodland suitability group.
distinct bluish gray (5B 5/1), and few
fine distinct dark bluish gray (5B 4/1) Maraguez series
mottles; massive; firm, slightly sticky
and plastic; few fine roots; few fine vol- The Maraguez series consists of well drained, very
canic rock fragments; few fine limestone steep soils on side slopes and narrow hilltops on the
fragments; few fine shell fragments; strongly dissected, humid uplands. These soils formed
slight effervescence; clear wavy bound- in moderately fine textured and medium textured re-
ary. siduum that derived from volcanic rock. The slope
C4g-29 to 37 inches; light olive brown (2.5Y ranges from 40 to 60 percent. The annual rainfall
5/6), greenish gray (5BG 5/1), and dark ranges from 55 to 70 inches, and the temperature
bluish gray (5B 4/1) clay; rubbed color ranges from 760 to 780 F.
is gray (5Y 5/1); massive; firm, sticky In a representative profile, the surface layer is dark
and plastic; common fine volcanic rock brown silty clay loam about 6 inches thick. The subsoil
fragments; few fine limestone frag- is about 15 inches thick. In the upper 6 inches it is
ments; few shell fragments; water table brown and dark brown, firm, slightly sticky and
at a depth of 32 inches; strong efferves- slightly plastic clay loam, and in the lower 9 inches it
cence; clear wavy boundary. is dark yellowish brown, friable, slightly sticky and
C5g-37 to 60 inches; olive (5Y 5/4), dark green- slightly plastic loam. The substratum, between depths
ish gray (5BG 4/1), gray (5Y 5/1), of 21 and 60 inches, is yellowish brown, friable,
light olive brown (2.5Y 5/4) clay; slightly sticky and slightly plastic loam.
rubbed color is dark greenish gray Maraguez soils are moderately permeable. They
(5GY 4/1); massive; firm, sticky and have a moderate available water capacity and high
plastic; few fine volcanic rock frag- natural fertility, and they are easy to work. Runoff is
ments; few fine limestone fragments; very rapid, and susceptibility to erosion is high.
few lime splotches; strong effervescence. Maraguez soils have been used for shade-grown cof-
In irrigated areas, the water table is at a depth of 18 fee and native pasture. Some acres are in brush. These
to 36 inches. The A horizon has hue of 10YR and 2.5Y, soils are best suited to use as native pasture and wood-
value of 3 and 4, and chroma of 2 or 3; it has gray land.
and brown mottles. The C horizon has hue of 10YR, Representative profile of Maraguez silty clay loam,
5Y, 5GY, 2.5Y, 5B, and 5BG, value of 4 and 5, and 40 to 60 percent slopes, eroded, 15 meters east of kilo-
chroma of 1 to 6. meter marker 16.1 on Highway 139:
Machuelo soils are on the same landscape as Cin- Ap-0 to 6 inches; dark brown (10YR 3/3) silty
trona, Constancia, Cortada, and San Anton soils, clay loam; moderate fine and medium
Machuelo soils have a lighter colored surface than that subangular blocky structure; firm,
of Cintrona soils. Unlike Constancia soils, which are slightly sticky and slightly plastic; many
somewhat poorly drained, and Cortada and San Anton fine and medium roots; few worm holes;
soils, which are well drained, Machuelo soils are poorly few fine and medium pebbles; slightly
drained. Cortada and San Anton soils are coarser tex- acid; clear wavy boundary.
turned than Machuelo soils. B2-6 to 12 inches; 60 percent brown (10YR
Ma-Machuelo clay. This is a nearly level soil in 4/3), and 40 percent dark brown (10YR
depressions on the flood plains in the semiarid area. 8/3) clay loam; weak fine and medium
It generally is in areas of about 50 to 200 acres. The subangular blocky structure; firm,
slope is 0 to 2 percent. slightly sticky and slightly plastic; few
Included in mapping are a few saline spots that have fine and medium roots; few worm holes;







PONCE AREA OF SOUTHERN PUERTO RICO 33
many fine volcanic rock fragments; dish brown and red clay about 5 inches thick. The
slightly acid; clear wavy boundary, subsoil is about 13 inches thick. In the upper 7 inches
B3-12 to 21 inches; dark yellowish brown it is red, firm, slightly sticky and plastic clay; and in
(10YR 4/4) loam; weak fine subangular the lower 6 inches it is red and yellowish red, friable,
blocky structure; friable, slightly sticky slightly sticky and plastic clay. The substratum, be-
and slightly plastic; few fine and me- tween depths of 18 and 60 inches, is red, yellowish red,
dium roots; common fine subangular vol- reddish brown, and reddish gray, friable, slightly
canic rock fragments; common fine sticky and slightly plastic clay. This layer is mainly
quartz grains; slightly acid; clear wavy saprolite.
boundary. Maricao soils are moderately permeable. They have
C-21 to 60 inches; yellowish brown (10YR a high available water capacity and low natural fer-
5/4) loam; massive; friable, slightly utility. They are difficult to work. Runoff is rapid to
sticky and slightly plastic; few fine and very rapid. These soils are highly susceptible to ero-
medium roots; common fine and medium sion.
volcanic rock fragments; many fine Most of these soils have been in native pasture for
quartz grains; medium acid. many years. There are small patches of shade-grown
The solum is 16 to 24 inches thick. The Ap horizon coffee and subsistence crops. Some areas are in aban-
has hue of 10YR, value of 3, and chroma of 2 and 3. doned coffee trees and brush. These soils are suitable
The B2 horizon has hue of 10YR, value of 3 and 4, and for pangolagrass.
chroma of 3. The B2 horizon is clay loam to loam, and Representative profile of Maricao clay, 20 to 60
the B3 horizon is loam or silt loam. percent slopes, eroded, 40 meters south of kilometer
Maraguez soils are on the same landscape as marker 3.4 on Highway 143:
Caguabo, Morado, Mficara, and Quebrada soils. They Ap-0 to 5 inches; 70 percent reddish brown
are deeper to rock than Caguabo soils and have coarser (5YR 4/4) and 30 percent red (2.5YR
textured B and C horizons than those of Morado, 5/8) clay; moderate fine and medium
Miicara, and Quebrada soils, granular structure; firm, slightly sticky
MeF2-Maraguez silty clay loam, 40 to 60 percent and plastic; many fine roots; 15 percent,
slopes, eroded. This is a very steep soil on side slopes by volume, is fine angular gravel; very
and narrow ridges on the humid uplands. It generally strongly acid; clear smooth boundary.
is in areas of about 100 to 200 acres. B2t-5 to 12 inches; red (2.5YR 5/8) clay; weak
Included in mapping are small areas of soils that medium subangular blocky structure;
have a coarser textured surface layer and calcareous firm, slightly sticky and plastic; many
substrata and areas of soils that have slopes of less fine roots; patchy clay films on ped sur-
than 40 percent. faces; 10 percent of horizon is saprolite;
Runoff is very rapid and erosion is a hazard. Deep 5 percent, by volume, is fine angular
gullies are common in drainageways. Generally, this gravel; very strongly acid; clear wavy
soil is not suitable for cultivation. Slips are common boundary.
in road cuts, ditches, and drainageways. The layout, B3-12 to 18 inches; red (2.5YR 5/8 and 10R
construction, and maintenance of ditches is very dif- 4/8) and yellowish red (5YR 5/8),
ficult and costly. Fertilizing pastures is not practical. rubbed color is yellowish red (5YR 4/6)
The root zone is deep. This soil is fertile. clay; weak fine subangular blocky struc-
Most of the acreage has been in native pasture of ture; friable, slightly sticky and plastic;
low carrying capacity. Some areas are in shade-grown few fine roots; few patchy clay films; 35
coffee and brush. This soil has very severe limitations percent, by volume, of horizon is sapro-
for cultivation because of steep slope, very rapid run- lite; very strongly acid; clear wavy
off, and the erosion hazard. It should be maintained boundary.
in permanent vegetation. It is suitable for use as native C-18 to 60 inches; variegated colors of the
pasture and woodland. Deferred grazing is helpful in saprolite are red, yellowish red, reddish
avoiding overgrazing, brown, and reddish gray clay; rubbed
Capability unit VIIe-2; woodland suitability group color is red (2.5YR 5/6); friable,
3rl. slightly sticky and slightly plastic; very
strongly acid.
Maricao series The solum is 15 to 22 inches thick. The Ap horizon
has hue of 5YR and 2.5YR, value of 4 and 5, and
The Maricao series consists of well drained, steep chroma of 4 and higher. The B2t horizon has hue of
and very steep soils on side slopes and narrow hilltops 2.5YR and 10R, value of 4 and 5, and chroma of 6 and
on the strongly dissected uplands. These soils formed 8. The B2t horizon ranges from weak medium to mod-
in fine textured residuum that was derived from basic rate fine and medium subangular blocky in structure.
volcanic rock. The slope ranges from 20 to 60 percent. Maricao soils are on the same landscape as Los
These soils are in areas where rainfall and altitude are Guineos soils. They have a thinner profile and are shal-
high and the mean annual soil temperature at a depth lower to saprolite than Los Guineos soils.
of 20 inches is lower than 720 F. The annual rainfall MkF2-Maricao clay, 20 to 60 percent slopes, eroded.
in these areas ranges from 90 to 100 inches, and the This is a steep and very steep soil on side slopes and
temperature ranges from 720 to 740 F. narrow ridges in areas of high altitude and high rain-
In a representative profile, the surface layer is red- fall. It is in areas of more than 500 acres.








34 SOIL SURVEY

Included in mapping are some areas of soils, espe- moist and olive gray (5Y 5/2) dry, fine
cially on ridges, that are severely eroded and other sand; single grain; loose, nonsticky and
areas of soils that are along drainageways that have nonplastic; many shell fragments;
more than 60 percent slopes, strong effervescence.
Runoff is rapid to very rapid; erosion is a hazard. The Al horizon is 10 to 20 inches thick. The cal-
Deep gullies are common in drainageways. Slips are careous horizon is at a depth between 30 and 54
common in road cuts, ditches, and drainageways. Lay- inches. The Al horizon has hue of 10YR, value of 3,
out, construction, and maintenance of ditches are dif- and chroma of 2 and 3.
ficult and costly. Liming and fertilizing are not Meros soils are on the same landscape as Serrano
practical. The root zone is deep. Because of the high soils, Hydraquents, and Hydraquents, saline. Unlike
altitude and the high rainfall, there are only a few Serrano soils and Hydraquents, saline, Meros soils are
adapted kinds of trees that have commercial value. nonsaline, and unlike Hydraquents, they are exces-
Most of the acreage of this soil is brushy woodland sively drained and are not saturated with water.
and pasture. Some areas are in native pasture of low Mr-Meros sand. This is a nearly level soil on benches
carrying capacity. This soil has severe limitations for along the coast. It generally is in areas of about 20 to
cultivation because of slope, rapid to very rapid run- 50 acres. The slope is 0 to 2 percent.
off, and the erosion hazard. Clearing the brush land Included in mapping are few narrow strips of beach
for pasture is costly. This soil should be maintained sand that has been reworked by waves, and small areas
in permanent vegetation to control erosion. of soils that have a calcareous surface layer.
Capability unit VIIe-1; woodland suitability group Runoff is slow. This soil is not subject to erosion. It
2c3. has very low available water capacity and natural
fertility. Occasionally there are long periods of
Meros series drought.
Irrigation is not feasible because permeability is
The Meros series consists of excessively drained, very rapid. Fertilizing is not practical. No kinds of
nearly level soils on benches along the coast at an grasses can adapt to this soil.
elevation slightly above sea level. These soils formed in This soil has been mainly in coconuts for many
coarse textured sediment that was derived from vol- years. Some areas are in brush, and other areas have
canic rock, sea shells, and coral. The slope ranges from no vegetation. This soil has a severe limitation for cul-
0 to 2 percent. The annual rainfall ranges from 25 to tivation because of very rapid permeability and very
40 inches, and the temperature ranges from 780 to low available water capacity. Coconuts grow well on
800 F. this soil.
In a representative profile, the surface layer is very Capability unit VIIs-1; not in a woodland suitabil-
dark grayish brown fine sand about 16 inches thick, ity group.
The substratum, between depths of 16 and 60 inches, is
fine sand. In the upper 8 inches it is dark brown; in the Montegrande series
next 6 inches it is very dark grayish brown; and in
the lowermost 30 inches it is very dark gray. The Montegrande series consists of moderately well
Meros soils are very rapidly permeable. They have drained, gently sloping to strongly sloping soils on
very low available water capacity and natural fertil- alluvial fans and foot slopes on the volcanic uplands.
ity. These soils generally are in coconuts and weeds. These soils formed in fine textured and gravelly tex-
Representative profile of Meros sand, 3 kilometers tured sediment that was derived from volcanic rock.
south of kilometer marker 125.1 on Highway 1: The slope ranges from 2 to 12 percent. The annual
Al-0 to 16 inches; very dark grayish brown rainfall ranges from 65 to 80 inches, and the tempera-
(10YR 3/2) moist, dark grayish brown ture ranges from 760 to 780 F.
(10YR 4/2) dry, fine sand; single grain; In a representative profile, the surface layer is very
loose, nonsticky and nonplastic; many dark grayish brown clay about 7 inches thick. The sub-
fine roots; common very fine volcanic soil is about 18 inches thick. In the upper 6 inches it
gravel; neutral; clear smooth boundary, is brown, dark yellowish brown, and very dark grayish
Cl-16 to 24 inches; dark brown (10YR 3/3) brown firm clay; and in the lowermost 5 inches it is
moist, grayish brown (10YR 5/2) dry, dark yellowish brown firm clay that has splotches of
fine sand; single grain; loose, nonsticky very dark grayish brown. The substratum, between
and nonplastic; few fine roots; neutral; depths of 25 and 60 inches, is dark yellowish brown,
clear smooth boundary. firm gravelly clay that has dark gray mottles.
C2-24 to 30 inches; very dark grayish brown Montegrande soils have moderately slow permeabil-
(2.5Y 3/2) moist, olive gray (5Y 4/2) ity. They have high available water capacity and nat-
dry, fine sand; single grain; loose, non- ural fertility, and they are difficult to work. Runoff is
sticky and nonplastic; few fine roots; slow to medium.
mildly alkaline; clear smooth boundary. Most of the acreage of these soils is in sugarcane.
C3-30 to 44 inches; very dark gray (5Y 3/1) Some small areas are used as native pasture and for
moist and olive gray (5Y 5/2) dry, fine food crops. These soils are well suited to paragrass,
sand; single grain; loose, nonsticky and pangolagrass, stargrass, and Merkergrass.
nonplastic; few fine roots; moderately Representative profile of Montegrande clay, 2 to 12
alkaline; clear smooth boundary. percent slopes, 500 meters north of kilometer marker
C4-44 to 60 inches; very dark gray (5Y 3/1) 11.2 on Highway 132:








34 SOIL SURVEY

Included in mapping are some areas of soils, espe- moist and olive gray (5Y 5/2) dry, fine
cially on ridges, that are severely eroded and other sand; single grain; loose, nonsticky and
areas of soils that are along drainageways that have nonplastic; many shell fragments;
more than 60 percent slopes, strong effervescence.
Runoff is rapid to very rapid; erosion is a hazard. The Al horizon is 10 to 20 inches thick. The cal-
Deep gullies are common in drainageways. Slips are careous horizon is at a depth between 30 and 54
common in road cuts, ditches, and drainageways. Lay- inches. The Al horizon has hue of 10YR, value of 3,
out, construction, and maintenance of ditches are dif- and chroma of 2 and 3.
ficult and costly. Liming and fertilizing are not Meros soils are on the same landscape as Serrano
practical. The root zone is deep. Because of the high soils, Hydraquents, and Hydraquents, saline. Unlike
altitude and the high rainfall, there are only a few Serrano soils and Hydraquents, saline, Meros soils are
adapted kinds of trees that have commercial value. nonsaline, and unlike Hydraquents, they are exces-
Most of the acreage of this soil is brushy woodland sively drained and are not saturated with water.
and pasture. Some areas are in native pasture of low Mr-Meros sand. This is a nearly level soil on benches
carrying capacity. This soil has severe limitations for along the coast. It generally is in areas of about 20 to
cultivation because of slope, rapid to very rapid run- 50 acres. The slope is 0 to 2 percent.
off, and the erosion hazard. Clearing the brush land Included in mapping are few narrow strips of beach
for pasture is costly. This soil should be maintained sand that has been reworked by waves, and small areas
in permanent vegetation to control erosion. of soils that have a calcareous surface layer.
Capability unit VIIe-1; woodland suitability group Runoff is slow. This soil is not subject to erosion. It
2c3. has very low available water capacity and natural
fertility. Occasionally there are long periods of
Meros series drought.
Irrigation is not feasible because permeability is
The Meros series consists of excessively drained, very rapid. Fertilizing is not practical. No kinds of
nearly level soils on benches along the coast at an grasses can adapt to this soil.
elevation slightly above sea level. These soils formed in This soil has been mainly in coconuts for many
coarse textured sediment that was derived from vol- years. Some areas are in brush, and other areas have
canic rock, sea shells, and coral. The slope ranges from no vegetation. This soil has a severe limitation for cul-
0 to 2 percent. The annual rainfall ranges from 25 to tivation because of very rapid permeability and very
40 inches, and the temperature ranges from 780 to low available water capacity. Coconuts grow well on
800 F. this soil.
In a representative profile, the surface layer is very Capability unit VIIs-1; not in a woodland suitabil-
dark grayish brown fine sand about 16 inches thick, ity group.
The substratum, between depths of 16 and 60 inches, is
fine sand. In the upper 8 inches it is dark brown; in the Montegrande series
next 6 inches it is very dark grayish brown; and in
the lowermost 30 inches it is very dark gray. The Montegrande series consists of moderately well
Meros soils are very rapidly permeable. They have drained, gently sloping to strongly sloping soils on
very low available water capacity and natural fertil- alluvial fans and foot slopes on the volcanic uplands.
ity. These soils generally are in coconuts and weeds. These soils formed in fine textured and gravelly tex-
Representative profile of Meros sand, 3 kilometers tured sediment that was derived from volcanic rock.
south of kilometer marker 125.1 on Highway 1: The slope ranges from 2 to 12 percent. The annual
Al-0 to 16 inches; very dark grayish brown rainfall ranges from 65 to 80 inches, and the tempera-
(10YR 3/2) moist, dark grayish brown ture ranges from 760 to 780 F.
(10YR 4/2) dry, fine sand; single grain; In a representative profile, the surface layer is very
loose, nonsticky and nonplastic; many dark grayish brown clay about 7 inches thick. The sub-
fine roots; common very fine volcanic soil is about 18 inches thick. In the upper 6 inches it
gravel; neutral; clear smooth boundary, is brown, dark yellowish brown, and very dark grayish
Cl-16 to 24 inches; dark brown (10YR 3/3) brown firm clay; and in the lowermost 5 inches it is
moist, grayish brown (10YR 5/2) dry, dark yellowish brown firm clay that has splotches of
fine sand; single grain; loose, nonsticky very dark grayish brown. The substratum, between
and nonplastic; few fine roots; neutral; depths of 25 and 60 inches, is dark yellowish brown,
clear smooth boundary. firm gravelly clay that has dark gray mottles.
C2-24 to 30 inches; very dark grayish brown Montegrande soils have moderately slow permeabil-
(2.5Y 3/2) moist, olive gray (5Y 4/2) ity. They have high available water capacity and nat-
dry, fine sand; single grain; loose, non- ural fertility, and they are difficult to work. Runoff is
sticky and nonplastic; few fine roots; slow to medium.
mildly alkaline; clear smooth boundary. Most of the acreage of these soils is in sugarcane.
C3-30 to 44 inches; very dark gray (5Y 3/1) Some small areas are used as native pasture and for
moist and olive gray (5Y 5/2) dry, fine food crops. These soils are well suited to paragrass,
sand; single grain; loose, nonsticky and pangolagrass, stargrass, and Merkergrass.
nonplastic; few fine roots; moderately Representative profile of Montegrande clay, 2 to 12
alkaline; clear smooth boundary. percent slopes, 500 meters north of kilometer marker
C4-44 to 60 inches; very dark gray (5Y 3/1) 11.2 on Highway 132:








PONCE AREA OF SOUTHERN PUERTO RICO 35

Ap-0 to 7 inches; very dark grayish brown to work because of the high clay content and the plas-
(10YR 3/2) clay; weak coarse subangu- ticity and stickiness of the clay.
lar blocky structure; very firm, sticky Tillage should be done at the optimum moisture con-
and plastic; many fine roots; many fine tent. Land leveling and smoothing are difficult because
subangular volcanic rock fragments; of poor workability, slope, and the gravelly layers in
apparently compacted by machinery; the substratum. The root zone is deep. This soil is
pressure faces; medium acid; clear fertile, and crops respond well to fertilizer, The use of
smooth boundary, machinery is feasible.
B1-7 to 13 inches; 60 percent dark brown In some areas this soil is in sugarcane and food
(10YR 3/3) and 40 percent brown crops. A large acreage is in native pasture. This soil
(10YR 4/3) clay; weak coarse subangu- has some limitations for cultivated crops because of
lar blocky structure; very firm, sticky the erosion hazard and the need for drainage. If prop-
and plastic; common fine roots; many erly managed and drained, it can be used for a wide
fine subangular volcanic rock fragments; range of food crops and as pasture. Paragrass, pango-
pressure faces; slightly acid; clear lagrass, and stargrass grow well on this soil, and
smooth boundary, merker grass can be used as green chop.
B2-13 to 20 inches; 60 percent brown (10YR Capability unit IIw-2; not in a woodland suitability
4/3), 25 percent dark yellowish brown group.
(10YR 4/4), and 15 percent very dark
grayish brown (10YR 3/2) clay; mas- Morado series
sive; firm, sticky and plastic; few fine
roots; common fine subangular volcanic The Morado series consists of well drained, steep and
rock fragments; cracks to a depth of 20 very steep soils on side slopes, foot slopes, and hilltops
inches; pressure faces and slickensides; on the strongly dissected, humid uplands. These soils
neutral; clear smooth boundary. are moderately deep to volcanic rock. They formed in
B3-20 to 25 inches; dark yellowish brown moderately fine textured residuum that was derived
(10YR 4/4) clay; splotches of very dark from pinkish volcanic rock. The slope ranges from 20
grayish brown (10YR 3/2) and a few to 60 percent. The annual rainfall ranges from 65 to
fine dark gray (10YR 4/1) mottles; mas- 88 inches, and the temperature ranges from 760 to
sive; firm, sticky and plastic; pressure 780 F.
faces and slickensides; mildly alkaline; In a representative profile, the surface layer is dark
clear smooth boundary, reddish gray clay loam about 6 inches thick. The sub-
IIC-25 to 60 inches; dark yellowish brown soil is about 18 inches thick. In the upper 10 inches it
(10YR 4/4) gravelly clay; common fine is reddish gray, friable clay loam; and in the lower 8
dark gray (10YR 4/1) mottles; mas- inches it is dark reddish gray, friable clay loam. The
sive; firm, slightly sticky and slightly substratum, between depths of 24 and 30 inches, is
plastic; fine and medium subangular vol- dark brown, dark reddish gray, and dark gray, friable
canic rock fragments make up more than clay loam saprolite. Reddish gray semiconsolidated vol-
40 percent of the horizon; mildly alka- canic rock is at a depth of 30 inches.
line. Morado soils are moderately permeable. They have a
Thickness of the solum and depth to the gravelly moderate available water capacity and high natural
clay layer range from 20 to 34 inches. The Ap horizon fertility, and they are easy to work. Runoff is rapid to
has hue of 10YR, value of 3 and 4, and chroma of 2, very rapid.
3, or 4. The B2 horizon is weak medium to coarse These soils have been used for food crops and shade-
subangular blocky or massive. The C horizon is 40 to grown coffee and as pasture. Some areas were formerly
60 percent volcanic rock fragments, used for coffee and brushy woodland.
Montegrande soils are on the same landscape as Representative profile of Morado clay loam, 20 to
Lares, Mucara, and Quebrada soils. Montegrande soils 40 percent slopes, eroded, 500 meters west of kilometer
are browner and less acidic than Lares soils. Unlike marker 15.0 on Highway 139:
Mucara and Quebrada soils, they are moderately well Ap-0 to 6 inches; dark reddish gray (10R 4/1)
drained and have gravelly clay layers in the substra- moist, dark gray (5YR 4/1) dry, clay
tum. loam; moderate fine and medium granu-
MsC-Montegrande clay, 2 to 12 percent slopes. This lar structure; friable, slightly sticky and
is a gently sloping to strongly sloping soil on alluvial plastic; many fine roots; 15 percent by
fans and foot slopes on volcanic hills. It generally is in volume is fine volcanic rock fragments;
areas of about 20 to 50 acres. medium acid; clear smooth boundary.
Included in mapping are small areas of soils that B2-6 to 16 inches; reddish gray (5YR 5/2) clay
are free of gravel throughout the profile and other loam; weak fine and medium subangular
areas of soils that have the gravelly layer closer to the blocky structure; friable, slightly sticky
surface, and plastic; many fine roots; 10 percent
Runoff is slow to medium. Erosion is a hazard. Some by volume is saprolite; slightly acid;
measures for controlling erosion are needed if culti- gradual smooth boundary.
vated crops are grown. Because permeability is mod- B3-16 to 24 inches; dark reddish gray (5YR
erately slow in the upper part of the profile, this soil 4/2) clay loam; weak fine subangular
needs to be drained. It has a plow layer that is difficult blocky structure parting to fine granu-








36 SOIL SURVEY
lar; friable, slightly sticky and plastic; Most of the acreage of this soil is in brushy wood-
few fine roots; 50 percent by volume is land and brushy pasture: Some small cleared areas are
saprolite; slightly acid; clear wavy in native pasture of low carrying capacity. A few areas
boundary, are in shade-grown coffee.
C-24 to 30 inches; variegated colors of the clay Because of very steep slopes, very rapid runoff, and
loam saprolte are dark brown (7.5YR the hazard of erosion, this soil has very severe limita-
4/2), dark Yeddish gray (5YR 4/2), and tions for cultivation. It should be under permanent
dark gray (5YR 4/1) ; massive; friable, vegetation such as trees or pasture grasses.
slightly sticky and slightly plastic; Capability unit VIIe-2; woodland suitability group
slightly acid. 3d3.
R-30 inches; reddish gray semiconsolidated vol-
canic rock. Mucara series
The solum is 16 to 30 inches thick. The Ap horizon ucara er
has hue of 10R and 2.5YR, value of 4 and 5, and The Mucara series consists of well drained, moder-
chroma of 1 and 2. The B2 horizon has hue of 2.5YR ately steep to very steep soils on foot slopes, side slopes,
and 5YR, value of 4 and 5, and chroma of 1 and 2. The and rounded hilltops on the strongly dissected, vol-
B2 horizon is weak fine to weak medium subangular canic uplands. These soils are moderately deep to vol-
blocky in structure. Depth to the semiconsolidated rock canic rock. They formed in fine textured residuum that
ranges from 20 to 36 inches. was derived from weathered volcanic rock. The slope
Morado soils are on the same landscape as Mucara, ranges from 12 to 60 percent. The annual rainfall
Caguabo, Maraguez, and Quebrada soils. Unlike those ranges from 60 to 80 inches, and the temperature
soils, Morado soils have a dark reddish gray surface ranges from 760 to 780 F.
layer. Morado soils have a thicker profile than Caguabo In a representative profile, the surface layer is very
soils, Morado soils are shallower to rock than Maraguez dark grayish brown silty clay about 5 inches thick.
and Quebrada soils. The subsoil is about 14 inches thick. In the upper 8
MtE2-Morado clay loam, 20 to 40 percent slopes, inches it is dark brown, firm silty clay; and in the
eroded. This is a steep soil on side slopes and hilltops lower 6 inches it is dark yellowish brown, yellowish
on the humid uplands. It generally is in areas of about brown, and dark brown, friable silty clay. The sub-
50 to 100 acres. This is the soil described as represen- stratum, between depths of 19 and 30 inches, is friable,
tative of the series. highly weathered volcanic rock. Semiconsolidated rock
Included in mapping are some areas of soils on foot is at a depth of 30 inches.
slopes where the slope is 20 percent and a few areas Mucara soils are moderately permeable. They have
of soils on hilltops where rocks and boulders are on moderate available water capacity and high natural
the surface. fertility. They are difficult to work. The organic mat-
Runoff is rapid. Erosion is a hazard. Deep gullies ter content is moderate.
are common in drainageways. This soil generally is These soils have been planted to a variety of crops.
not suited to cultivation. The layout, construction, and Some areas are in native pasture, shade-grown coffee,
maintenance of ditches are difficult and costly. This and pangolagrass. A large acreage is in brushy pasture
soil is easy to work. The root zone is moderately deep. and brushy woodland.
This soil is fertile, and crops respond well to fertilizer. Representative profile of Micara silty clay, 40 to 60
Most of the acreage of this soil is in native pasture percent slopes, eroded, 700 meters south of kilometer
of low carrying capacity. Some areas are in brushy marker 6.3 on Highway 143:
woodland, brushy pasture, and shade-grown coffee. Oc- Ap-0 to 5 inches; very dark grayish brown
casionally food crops are planted. (10YR 3/2) silty clay; weak fine and
This soil has a severe limitation for cultivated crops medium granular structure; friable,
because of slope, rapid runoff, and the hazard of ero- slightly sticky and plastic; many fine
sion. It should be maintained in permanent vegetation, roots; 10 percent, by volume, is fine and
It is well suited to pangolagrass, stargrass, and guinea- medium volcanic rock fragments; me-
grass. Deferred grazing is helpful in maintaining good dium acid; clear smooth boundary.
pasture and controlling erosion. This soil is suited to B2-5 to 13 inches; dark brown (10YR 4/3) silty
use as woodland. clay; weak medium subangular blocky
Capability unit VIe-3; woodland suitability group structure; firm, slightly sticky and plas-
3d2. tic; many fine roots; 5 percent, by vol-
MtF2-Morado clay loam, 40 to 60 percent slopes, ume, fine and medium volcanic rock
eroded. This is a very steep soil on side slopes and fragments; medium acid; clear wavy
ridges on the humid uplands. It generally is in areas of boundary.
about 100 to 500 acres. This soil has a thinner profile B3-13 to 19 inches; dark yellowish brown
than the one described as representative of the series. (10YR 4/4), yellowish brown (10YR
Runoff is very rapid. This soil is very erosive. Very 5/4), and dark brown (10YR 4/3) silty
deep gullies are common in drainageways. This soil is clay; weak medium subangular blocky
not suited to cultivation. The layout, construction, and structure; friable, slightly sticky and
maintenance of ditches and the application of fertili- slightly plastic; few fine roots; 30 per-
zer are very difficult and costly. The root zone is mod- cent of horizon is saprolite; slightly
erately deep. acid; clear wavy boundary.








PONCE AREA OF SOUTHERN PUERTO RICO 37

C-19 to 30 inches; friable, neutral, highly weath- ageways. The layout, construction, and maintenance
ered volcanic rock. of ditches are difficult and costly. The root zone is mod-
R-30 inches; semiconsolidated volcanic rock. erately deep. This soil is fertile, and crops respond well
The solum is 14 to 20 inches thick. The Ap horizon to fertilizer.
has hue of 10YR, value of 3, and chroma of 2 or 3. The Most of the acreage of this soil is in native pasture
B2 horizon has hue of 10YR, value of 4, and chroma and brushy woodland. Some small areas are planted to
of 3 or 4. The B2 horizon is silty clay or clay. The food crops, and some areas are in shade-grown coffee.
B2 horizon is weak fine or weak medium subangular Because of slope, runoff, and the hazard of erosion,
blocky in structure. Depth to the semiconsolidated vol- this soil is not suitable for cultivation. It should be
canic rock ranges from 20 to 36 inches, maintained in permanent vegetation. Pangolagrass
Mucara soils are on the same landscape as Morado, and stargrass grow well on this soil. Deferred grazing
Quebrada, Maraguez, and Caguabo soils. Unlike Morado is necessary to avoid overgrazing. This soil is suitable
soils, which have a dark reddish gray, moderately fine for use as woodland.
textured surface layer, Mucara soils have a very dark Capability unit VIe-3; woodland suitability group
grayish brown, fine textured surface layer. Mucara 3d2.
soils are shallower to the semiconsolidated volcanic MuF2-Mucara silty clay, 40 to 60 percent slopes,
rock than Quebrada and Maraguez soils. Mucara soils eroded. This is a very steep soil on side slopes and nar-
are deeper to volcanic rock than Caguabo soils. row ridges on the humid uplands. The areas generally
MuD2-Mucara silty clay, 12 to 20 percent slopes, are more than 500 acres in size. This is the soil de-
eroded. This is a moderately steep soil on foot slopes, scribed as representative of the series.
side slopes, and rounded hilltops on the humid uplands. Included in mapping are many very small areas of
It generally is in areas of about 20 to 50 acres. This soils that have many rocks and boulders on the surface
soil is similar to the one described as representative and many areas of severely eroded soils that have sub-
of the series, except it has a thicker surface layer, is on stratum material in the surface layer.
less steep slopes, and has been less affected by erosion. Runoff is very rapid. This soil is very erodible. It is
Included in mapping are soils on a few narrow foot not suitable for cultivation. Large gullies are common
slopes where the slope is less than 12 percent. These in drainageways. Slips are common in road cuts and
soils have a thicker surface layer than this Mucara ditches. The layout, construction, and maintenance of
soil. ditches and the application of fertilizer are very dif-
Runoff is medium. Erosion is a hazard. Gullies are ficult and costly. Establishing a good species of grass is
common in drainageways. Some measures for control- difficult and costly.
ling erosion are needed if cultivated crops are grown. This soil has mainly been in brushy woodland and
This soil has a plow layer that is somewhat difficult to brushy pasture. Some small areas are in native pasture
work because of the stickiness and plasticity of the of low carrying capacity. Occasionally, food crops are
clay. The root zone is moderately deep. This soil is grown in some small areas.
fertile, and crops respond well to fertilizer. This soil is not suitable for cultivation because of
Most of the acreage of this soil has been in native slope, runoff, and the erosion hazard. It should be
pasture. Some areas are in shade-grown coffee, and a maintained in permanent vegetation to control ero-
few areas are in food crops. If used for cultivated sion.
crops, this soil has limitations because of slope, runoff, Capability unit VIIe-2; woodland suitability group
and the hazard of erosion. Intensive cropping on this 3d3.
soil is not feasible. This soil is suited to most of the
food crops grown in the area. Stripcropping and crop Paso Seco series
rotation are helpful in controlling erosion. Native pas-
ture grasses, pangolagrass, and stargrass grow well on The Paso Seco series consists of moderately well
this soil and provide a good cover. Deferred grazing is drained, gently sloping soils on alluvial fans and ter-
helpful in avoiding overgrazing. This soil is suitable races that are slightly higher than the flood plain.
for use as woodland. These soils formed in fine textured sediment of mixed
Capability unit IVe-2; woodland suitability group origin over gravelly fine textured sediment. The slope
3d2. ranges from 2 to 5 percent. The annual rainfall ranges
MuE2-Mucara silty clay, 20 to 40 percent slopes, from 25 to 40 inches, and the temperature ranges from
eroded. This is a steep soil on side slopes and ridges on 780 to 800 F.
the humid uplands. It generally is in areas of about 50 In a representative profile, the surface layer is very
to 200 acres. This soil is similar to the one described as dark grayish brown clay about 10 inches thick. The
representative of the series, except it has a slightly subsurface layer is dark yellowish brown and very dark
thicker surface layer. grayish brown, firm clay about 5 inches thick. The
Included in mapping are many narrow strips of soils next layer, between depths of 15 to 25 inches, is dark
along drainageways that have more than 40 percent yellowish brown, firm clay. The substratum, between
slopes. Also included are a few areas of soils on foot depths of 25 and 32 inches, is dark yellowish brown,
slopes that have less than 20 percent slopes and areas friable gravelly clay, and between depths of 32 to 60
on some hilltops that have many rocks and boulders on inches it is friable sand, gravel, and silt that has very
the surface, little clay.
Runoff is rapid. Erosion is a hazard. This soil is not Paso Seco soils are slowly permeable. They have high
suited to cultivated crops. Gullies are common in drain- available water capacity and natural fertility. They are








38 SOIL SURVEY

difficult to work. Runoff is slow. The content of organic poor because the clay is sticky and plastic. This soil has
matter is high. hard clods when it is dry, and tillage should be done
These soils are suited to sugarcane and have been at the optimum moisture content. Land leveling is not
planted to this crop for many years where irrigation helpful because of the gravelly layers below a depth of
water is available. If they are not irrigated, these soils 20 inches. Land smoothing is difficult because of poor
are used for native pasture grasses, mainly Angleton- workability. The root zone is deep. This soil is fertile,
grass and guineagrass. and crops respond well to fertilizer.
Representative profile of Paso Seco clay, 2 to 5 per- Most of the acreage of this soil has been planted to
cent slopes, 100 meters west of kilometer marker 2.6 sugarcane under irrigation management for many
on Highway 543: years. Sugarcane is the best adapted crop. Those
Ap-0 to 10 inches; very dark grayish brown areas that are not under irrigation are in guineagrass
(10YR 3/2) clay; weak medium and and Angletongrass.
coarse subangular blocky structure; Capability units IIs-2, irrigated, and IIIc-1, non-
firm, sticky and plastic; many fine roots; irrigated; not in a woodland suitability group.
many fine volcanic rock fragments; pres-
sure faces; 1 inch of self-mulch soil; Pellejas series
mildly alkaline; clear smooth boundary.
A12-10 to 15 inches; 60 percent dark yellowish The Pellejas series consists of somewhat exces-
brown (10YR 4/4) and 40 percent very sively drained, very steep soils on short side slopes and
dark grayish brown (10YR 3/2) clay; narrow ridges on the strongly dissected, humid up-
rubbed color is dark yellowish brown lands. These soils formed in moderately fine textured
(10YR 3/4); massive; firm, sticky and over coarse textured and moderately coarse textured
plastic; many fine roots; many fine vol- residuum that weathered from plutonic rocks. The
canic rock fragments; pressure faces; slope ranges from 40 to 60 percent. The annual rainfall
cracks 3 to 5 inches wide to a depth of ranges from 70 to 90 inches, and the temperature
15 inches; mildly alkaline; abrupt smooth ranges from 760 to 780 F.
boundary. In a representative profile, the surface layer is dark
AC-15 to 25 inches; dark yellowish brown grayish brown clay loam about 5 inches thick. The
(10YR 4/4) clay; massive; firm, sticky subsoil is about 10 inches thick. In the upper 6 inches
and plastic; few fine roots; few medium it is dark brown, firm clay loam, and in the lower 4
pebbles; many very fine pebbles; pres- inches it is pale brown and dark yellowish brown, fri-
sure faces; mildly alkaline; clear smooth able sandy loam. The substratum, between depths of
boundary. 15 and 60 inches, is light brownish gray, very friable
IIC1-25 to 32 inches; dark yellowish brown loamy sand.
(10YR 4/4) gravelly clay; massive; fri- Pellejas soils have moderately rapid permeability.
able; slightly sticky and plastic; few They have a moderate available water capacity and
fine roots; mildly alkaline; abrupt low natural fertility. They are easy to work. Runoff is
smooth boundary, very rapid. These soils are highly susceptible to ero-
IIIC2-32 to 60 inches; friable, nonsticky and sion.
nonplastic; moderately alkaline sand, These soils have been used as native pasture and for
gravel, and silt with very little clay. shade-grown coffee and food crops. In a few areas they
The Ap horizon is 6 to 12 inches thick. The gravelly are in brush.
layer is at a depth between 20 and 32 inches. The Ap Representative profile of Pellejas clay loam, 40 to
horizon has hue of 10YR, value of 3, and chroma of 2 60 percent slopes, eroded, 100 meters north of kilo-
or 3. meter marker 44.5 on Highway 10:
Paso Seco soils are on the same landscape as Fe, Ap-0 to 5 inches; dark grayish brown (10YR
Fraternidad, Serrano, and Teresa soils. Unlike Fe, Ser- 4/2) clay loam; moderate fine granular
rano, and Teresa soils, Paso Seco soils are nonsaline. structure; firm, slightly sticky and
Unlike Fe and Fraternidad soils, Paso Seco soils have slightly plastic; many fine roots; many
gravel in the substratum. fine quartz grains; strongly acid; clear
PaB-Paso Seco clay, 2 to 5 percent slopes. This is a smooth boundary.
gently sloping soil on alluvial fans and terraces on the B2-5 to 11 inches; dark brown (10YR 4/3) clay
coastal plain in the semiarid area. It generally is in loam; weak medium subangular blocky
areas of about 50 to 200 acres. structure; firm, slightly sticky and plas-
Included in mapping are some areas of soils that tic; many fine roots; common fine and
have calcareous gravelly layers below a depth of 20 few medium quartz grains; strongly
inches. Also included are small areas of soils that are acid; clear wavy boundary.
dark reddish brown in the surface and subsurface B3-11 to 15 inches; 80 percent pale brown
layers and some areas of soils that are deeper to the (10YR 6/3) and 20 percent dark yellow-
gravelly layers than this Paso Seco soil. ish brown (10YR 4/4) sandy loam,
Runoff is slow. If properly managed, this soil can rubbed color is light brownish gray
be used for intensive cropping without loss of soil ma- (2.5Y 6/2); weak fine and medium sub-
terial. Because of low, poorly distributed rainfall, this angular blocky structure; friable, non-
soil needs to be irrigated. Shallow furrows are helpful sticky and slightly plastic; common fine
in avoiding the more permeable layers. Workability is roots; many fine quartz grains; many








PONCE AREA OF SOUTHERN PUERTO RICO 39

fine white and black specks; strongly in native pasture of low carrying capacity. Some areas
acid; clear wavy boundary. are in brushy woodland or brushy pasture.
C-15 to 60 inches; light brownish gray (2.5Y Representative profile of Quebrada silty clay loam,
6/2) loamy sand; single grain; very fri- 20 to 40 percent slopes, eroded, 10 meters east of dirt
able, nonsticky and nonplastic; strongly road, 1.7 kilometers from kilometer marker 5.9 on
acid. Highway 151:
The solum is 11 to 20 inches thick. The Ap horizon Ap-0 to 7 inches; dark brown (10YR 3/3) silty
has hue of 10YR, value of 4, and chroma of 2 or 3. The clay loam; moderate fine and medium
B2 horizon has hue of 10YR, value of 4, and chroma of granular structure; hard, firm, slightly
3 or 4. The B2 horizon is clay loam to loam. The B3 sticky and plastic; many fine roots;
horizon is sandy loam to loamy sand. common fine black concretions; 10 per-
Pellejas soils are on the same landscape as Lirios cent, by volume, is subangular volcanic
soils. Pellejas soils are shallower to saprolite and are rock fragments; slightly acid; clear
coarser textured throughout the profile than Lirios smooth boundary.
soils. Unlike Lirios soils, they have a brown B horizon. B-7 to 14 inches; dark yellowish brown (10YR
PeF2-Pellejas clay loam, 40 to 60 percent slopes, 4/4) silty clay; weak medium subangu-
eroded. This is a very steep soil on side slopes and very lar blocky structure; firm, slightly sticky
narrow ridges on the humid uplands. The areas gener- and plastic; common fine roots; neutral;
ally are more than 100 acres in size. gradual wavy boundary.
Included in mapping are many small areas of soils C-14 to 60 inches; weathered material with
that have less than 40 percent slopes and many small variegated colors of very dark brown,
areas of soils that are severely eroded. gray, and greenish gray; silty clay
Runoff is very rapid. This soil is very erodible. Rills loam; massive; friable, slightly sticky,
are common, and deep gullies are common in drainage- nonplastic; neutral.
ways. Slips are common in road cuts, ditches, and The solum is 12 to 18 inches thick. The Ap horizon
drainageways. This soil is not suitable for cultivation, has hue of 10YR, value of 3 or 4, and chroma of 3. The
The layout, construction, and maintenance of ditches B horizon has hue of 10YR, value of 4 or 5, and chroma
and the application of lime and fertilizer are difficult of 4 and higher. The B horizon is silty clay or clay. The
and costly. Establishing a good species of grass is B horizon is weak fine or weak medium subangular
costly. The root zone is deep. This soil has low natural blocky in structure.
fertility. Frequently, the pasture grasses and crops suf- Quebrada soils are on the same landscape as Mucara,
fer because of the lack of moisture in this soil. Caguabo, Morado, and Maraguez soils. They are
Most of the acreage is in native pasture. A few small deeper to rock than Mucara, Caguabo, and Morado
areas are planted to pangolagrass, and some areas are soils. They have finer textured B and C horizons than
in shade-grown coffee. Maraguez soils.
Because of slope, runoff, and the erosion hazard, this QeD2-Quebrada silty clay loam, 12 to 20 percent
soil is not suitable for cultivation. It should be main- slopes, eroded. This is a moderately steep soil on side
trained in permanent vegetation such as pasture grasses slopes and rounded hilltops on the humid uplands. The
or trees. areas generally are about 50 to 100 acres in size. This
Capability unit VIIe-5; woodland suitability group soil is similar to the one described as representative of
3rl. the series, except it has a thicker surface layer and
subsoil and has been less affected by erosion.
Quebrada series Included in mapping are soils on some narrow foot
slopes where the slope is less than 12 percent. These
The Quebrada series consists of well drained, mod- soils have a much thicker surface layer than this
erately steep to very steep soils on foot slopes, side Quebrada soil.
slopes, and hilltops on the strongly dissected, humid Runoff is medium. Erosion is a hazard. Rills are
uplands. These soils formed in moderately fine textured common. There are some deep gullies in drainageways.
and fine textured residuum that was derived from vol- Erosion needs to be controlled if cultivated crops are
canic rock. The slope ranges from 12 to 60 percent, grown. This soil is easy to work. The root zone is deep.
The annual rainfall ranges from 70 to 80 inches, and This soil is fertile, and crops respond well to fertilizer.
the temperature ranges from 760 to 78 F. This soil has been used for food crops, mainly corn
In a representative profile, the surface layer is dark and pigeonpeas. Some areas are in pasture grasses,
brown silty clay loam about 7 inches thick. The subsoil mainly pangolagrass. Some areas are in shade-grown
is dark yellowish brown, firm silty clay about 7 inches coffee and native pasture.
thick. The substratum, between depths of 14 and 60 This soil is suitable for cultivation if properly man-
inches, is very dark brown, gray, and greenish gray, aged using a good crop rotation and other practices
friable, slightly sticky and nonplastic silty clay loam to control erosion. It is suited to a wide range of crops.
saprolite. Pangolagrass, guineagrass, and stargrass are well
Quebrada soils are moderately permeable. They have adapted to this soil.
moderate to high available water capacity and high Capability unit IVe-2; woodland suitability group
natural fertility. They are easy to work. Runoff is me- 2c4.
dium to very rapid. QeE2-Quebrada silty clay loam, 20 to 40 percent
These soils have been planted to food crops, shade- slopes, eroded. This is a steep soil on side slopes and
grown coffee, and pasture grasses. A large acreage is hilltops on the humid uplands. It generally is in areas








40 SOIL SURVEY

of about 50 to 200 acres. This is the soil described as In a representative profile, the surface layer is very
representative of the series, dark grayish brown gravelly loam about 8 inches thick.
Included in mapping are narrow strips of soils along The substratum, between depths of 8 and 60 inches,
drainageways where the slope is more than 40 percent. is coarse sand and fine and coarse gravel.
Also included are some areas of severely eroded soils Reilly soils are rapidly permeable. They have a low
on ridges where substratum material is in the surface available water capacity and are easy to work. Runoff
layer and some areas of Mucara silty clay. is slow.
Runoff is rapid. Erosion is a hazard. Rills are com- These soils have been used mainly as pasture. Small
mon. Deep gullies are common in drainageways. This areas adjacent to the deeper soils are planted to sugar-
soil generally is not suitable for cultivation. Slips are cane, and a very small acreage has been used for food
common in road cuts, ditches, and drainageways. The crops.
layout, construction, and maintenance of ditches are Representative profile of Reilly gravelly loam, 500
difficult and costly. The root zone is deep. This soil is meters south of kilometer marker 1.2 on Highway
fertile, and crops respond well to fertilizer. 150:
A large acreage is in native pasture of low carrying Ap-0 to 8 inches; very dark grayish brown
capacity. Some areas are in brushy pasture and brushy (10YR 3/2) gravelly loam; weak fine
woodland. Other areas are planted periodically to food granular structure; friable, slightly
crops, mainly pigeonpeas. sticky and slightly plastic; many fine
Because of slope, runoff, and the hazard of erosion, roots; medium acid; abrupt smooth
this soil is not suitable for clean cultivation. It should boundary.
be maintained in permanent vegetation of pasture C1-8 to 16 inches; dark grayish brown (10YR
grasses or trees. Pangolagrass, stargrass and guinea- 4/2) gravelly sand; 50 percent, by vol-
grass adapt well to this soil. Deferred grazing is ume, fine gravel; single grain; slightly
necessary to avoid overgrazing and to control erosion. acid; abrupt smooth boundary.
Capability unit VIe-3; woodland suitability group C2-16 to 60 inches; 30 percent coarse sand and
2c4. 70 percent fine and coarse gravel.
QeF2-Quebrada silty clay loam, 40 to 60 percent The Ap horizon is 6 to 14 inches thick. It has hue of
slopes, eroded. This is a very steep soil on side slopes, 10YR, value of 3, and chroma of 2 or 3.
narrow ridges, and along drainageways on the humid Reilly soils are on the same landscape as Toa soils.
uplands. It generally is in areas of more than 500 They are coarser textured and shallower than Toa
acres. This soil is similar to the one described as soils.
representative of the series, except it has a thinner Re-Reilly gravelly loam. This is a nearly level soil
surface layer and subsoil. in narrow strips adjacent to rivers and streams on the
Included in mapping are a few ridges where the humid flood plains. It generally is in areas of about 5
soils have a large amount of rocks and boulders on the to 20 acres. In some areas this soil has stones and
surface. Also included are some areas of Mucara silty cobbles on the surface. Slopes are 0 to 2 percent.
clay loam and areas of eroded soils that have sub- Included in mapping are some small areas of River-
stratum material in the surface layer. wash.
Runoff is very rapid. This soil is very erodible. Very Runoff is slow. Erosion is not a hazard. Flooding is
deep gullies are common in drainageways. Slips in frequent in most years, generally from June to
road cuts and ditches are common. This soil is not October. Because of the rapid permeability and low
suitable for cultivation. The layout, construction, and available water capacity of this soil, plants suffer from
maintenance of ditches, the application of fertilizer, a lack of moisture in most years from December to
and the establishment of a good species of grass are April. Furrow irrigation is not feasible because the
very difficult and costly. stability of ditchbanks is poor.
Most of the acreage has been in brushy pasture and The plow layer is easy to till. Shallow plowing is
brushy woodland. Some areas are occasionally planted needed to avoid turning the coarser material to the
to food crops, mainly pigeonpeas. Some areas are in surface. The root zone is limited by low fertility and
cleared native pasture. by the lack of moisture in the coarse textured layers
Because of slope, runoff, and the erosion hazard, this below the surface layer. Fertility generally is low. The
soil should be maintained in permanent vegetation use of machinery on this soil is feasible.
such as pasture grasses or trees. Most of the acreage is in native pasture, a few areas
Capability unit VIIe-2; woodland suitability group are in pangolagrass and stargrass, and a very few
3rl. acres are in food crops.
Because of frequent flooding and the low available
Reilly series water capacity, the use of this soil for cultivation is
mainly restricted to such shallow-rooted crops as
The Reilly series consists of excessively drained, vegetables.
nearly level soils adjacent to the rivers and streams In most years supplementary irrigation by sprin-
on the humid flood plains. These soils are underlain klers is necessary. The duration and frequency of
by stratified layers of sand and gravel. They formed in irrigation depend on the kind of vegetables grown.
medium textured and coarse textured sediment of Pangolagrass and stargrass grow well on this soil.
mixed origin. Slopes are 0 to 2 percent. The annual Merkergrass is well suited as green chop.
rainfall is 60 to 80 inches, and the temperature is Capability unit IVs-1; not in a woodland suitability
760 to 78' F. group.








PONCE AREA OF SOUTHERN PUERTO RICO 41

Riverwash subsoil, between depths of 27 and 34 inches, is dark
yellowish brown, firm silty clay loam. The substratum,
Rw-Riverwash. This map unit consists of nearly between depths of 34 to 40 inches, is dark yellowish
level areas close to rivers and streams. It is in narrow brown, friable loam; between depths of 40 and 46
strips and in river channels. In places, stones and inches, it is dark brown, friable loam; between depths
boulders are numerous on the surface. Other areas of 46 and 52 inches, it is dark yellowish brown, friable
consist of a mixture of sand, gravel, and cobbles. silt loam; and between depths of 52 and 60 inches, it
Most areas of this map unit have no vegetation, is dark yellowish brown, friable clay loam.
Riverwash has no agricultural value. In general, it has San Anton soils have moderate permeability. They
severe limitations for nonfarm uses because of very have moderate to high available water capacity and
frequent flooding and the large amount of coarse high natural fertility. They are easy to work. Runoff
material on the surface. is slow. The organic matter content is high.
Machinery has been set up close to the river chan- For many years these soils have been planted to
nels to grind and separate the coarse material by sugarcane under irrigation management (fig. 4).
sizes. This material is used in the construction of Small areas where irrigation is not feasible are used as
buildings and highways. pasture. Some areas are planted to vegetables.
Capability unit VIIIs-2; not in a woodland suit- Representative profile of San Anton clay loam, 9
ability group. meters west of kilometer marker 2.35 on Highway
506:
San Anton series Ap-0 to 9 inches; very dark brown (10YR 2/2)
clay loam; weak fine granular structure;
The San Anton series consists of well drained, friable, slightly sticky and slightly plas-
nearly level soils on flood plains in the semiarid area. tic; many fine roots; many fine rounded
These soils formed in medium textured and moderately volcanic pebbles; moderately alkaline;
fine textured sediment that was derived from lime- abrupt smooth boundary.
stone and volcanic rock. The slope ranges from 0 to 2 All-9 to 22 inches; very dark brown (10YR
percent. The annual rainfall ranges from 25 to 40 2/2) clay loam; weak fine subangular
inches, and the temperature ranges from 780 to 800 F. blocky structure; firm, slightly sticky
In a representative profile, the surface layer is very and slightly plastic; common fine roots;
dark brown clay loam about 9 inches thick. The sub- many fine rounded volcanic pebbles;
surface layer is about 18 inches thick. In the upper 13 neutral; abrupt smooth boundary.
inches it is very dark brown, firm clay loam, and in A12-22 to 27 inches; dark brown (10YR 3/3)
the lower 5 inches it is dark brown, friable loam. The loam; weak fine subangular blocky


























Figure 4.-If properly managed, the San Anton soils are well suited to sugarcane. Steep and shallow Callabo soils are in the
background.








PONCE AREA OF SOUTHERN PUERTO RICO 41

Riverwash subsoil, between depths of 27 and 34 inches, is dark
yellowish brown, firm silty clay loam. The substratum,
Rw-Riverwash. This map unit consists of nearly between depths of 34 to 40 inches, is dark yellowish
level areas close to rivers and streams. It is in narrow brown, friable loam; between depths of 40 and 46
strips and in river channels. In places, stones and inches, it is dark brown, friable loam; between depths
boulders are numerous on the surface. Other areas of 46 and 52 inches, it is dark yellowish brown, friable
consist of a mixture of sand, gravel, and cobbles. silt loam; and between depths of 52 and 60 inches, it
Most areas of this map unit have no vegetation, is dark yellowish brown, friable clay loam.
Riverwash has no agricultural value. In general, it has San Anton soils have moderate permeability. They
severe limitations for nonfarm uses because of very have moderate to high available water capacity and
frequent flooding and the large amount of coarse high natural fertility. They are easy to work. Runoff
material on the surface. is slow. The organic matter content is high.
Machinery has been set up close to the river chan- For many years these soils have been planted to
nels to grind and separate the coarse material by sugarcane under irrigation management (fig. 4).
sizes. This material is used in the construction of Small areas where irrigation is not feasible are used as
buildings and highways. pasture. Some areas are planted to vegetables.
Capability unit VIIIs-2; not in a woodland suit- Representative profile of San Anton clay loam, 9
ability group. meters west of kilometer marker 2.35 on Highway
506:
San Anton series Ap-0 to 9 inches; very dark brown (10YR 2/2)
clay loam; weak fine granular structure;
The San Anton series consists of well drained, friable, slightly sticky and slightly plas-
nearly level soils on flood plains in the semiarid area. tic; many fine roots; many fine rounded
These soils formed in medium textured and moderately volcanic pebbles; moderately alkaline;
fine textured sediment that was derived from lime- abrupt smooth boundary.
stone and volcanic rock. The slope ranges from 0 to 2 All-9 to 22 inches; very dark brown (10YR
percent. The annual rainfall ranges from 25 to 40 2/2) clay loam; weak fine subangular
inches, and the temperature ranges from 780 to 800 F. blocky structure; firm, slightly sticky
In a representative profile, the surface layer is very and slightly plastic; common fine roots;
dark brown clay loam about 9 inches thick. The sub- many fine rounded volcanic pebbles;
surface layer is about 18 inches thick. In the upper 13 neutral; abrupt smooth boundary.
inches it is very dark brown, firm clay loam, and in A12-22 to 27 inches; dark brown (10YR 3/3)
the lower 5 inches it is dark brown, friable loam. The loam; weak fine subangular blocky


























Figure 4.-If properly managed, the San Anton soils are well suited to sugarcane. Steep and shallow Callabo soils are in the
background.








42 SOIL SURVEY

structure; friable, slightly sticky and Serrano series
slightly plastic; few fine roots; neutral;
clear wavy boundary. The Serrano series consists of poorly drained, saline,
B-27 to 34 inches; dark yellowish brown (10YR nearly level soils on the coastal plain adjacent to the
4/4) silty clay loam; weak fine subangu- beach in the semiarid area. These soils formed in
lar blocky structure; firm, slightly sticky coarse textured to moderately fine textured sediment
and slightly plastic; few fine roots; over coarse textured sediment. The slope ranges from
neutral; clear wavy boundary. 0 to 2 percent. The annual rainfall ranges from 20 to
IIC1-34 to 40 inches; dark yellowish brown 30 inches, and the temperature ranges from 780 to
(10YR 4/4) silt loam; massive; friable, 800 F.
slightly sticky and slightly plastic; neu- In a representative profile, the surface layer is very
tral; abrupt smooth boundary. dark grayish brown sand about 4 inches thick. The
IIC2-40 to 46 inches; dark brown (10YR 3/3) subsurface layer is very dark grayish brown, friable
loam; massive; friable, slightly sticky sandy loam about 5 inches thick. The subsoil, between
and slightly plastic; neutral; abrupt depths of 9 and 14 inches, is dark grayish brown, firm
smooth boundary. sandy clay loam. The substratum, between depths of
IIC3-46 to 52 inches; dark yellowish brown 14 and 21 inches, is very dark grayish brown, friable
(10YR 4/4) silt loam; massive; friable, loamy sand, and between depths of 21 and 60 inches,
slightly sticky and slightly plastic; it is very dark gray, friable sand.
mildly alkaline; abrupt smooth bound- Serrano soils are rapidly permeable. They have low
ary. available water capacity and very low natural fertility.
IIIC4-52 to 60 inches; dark yellowish brown They are easy to work. Runoff is slow.
(10YR 4/4) clay loam; massive; friable, These soils have been in salt-tolerant weeds, and in
slightly sticky and slightly plastic; some areas they are barren of vegetation.
mildly alkaline. Representative profile of Serrano sand, 3.6 kilo-
The solum is 28 to 42 inches thick. The A horizon meters south of kilometer marker 123.75, on Highway
has hue of 10YR, value of 2 and 3, and chroma of 2 and 1:
3. The B horizon has hue of 10YR, value of 4, and All-0 to 4 inches; very dark grayish brown
chroma of 4 and higher. The B horizon is silt loam, (2.5Y 3/2) sand; few fine faint dark
clay loam, or silty clay loam. It is weak fine or weak grayish brown (10YR 4/2) mottles;
medium subangular blocky in structure. The C horizon single grain; very friable, nonsticky,
is clay loam, silt loam, or loam. The B and C horizons nonplastic, many fine roots; very
are neutral to mildly alkaline. strongly alkaline; clear smooth bound-
San Anton soils are on the same landscape as ary.
Cortada, Machuelo, Cintrona, and Constancia soils. A12-4 to 9 inches; very dark grayish brown
Unlike Cortada soils, San Anton soils are noncalcar- (2.5Y 3/2) sandy loam; common fine
eous. Unlike Machuelo and Cintrona soils, which are faint dark grayish brown (10YR 4/2)
poorly drained and fine textured, San Anton soils are and many fine distinct black (N 2/ )
well drained and are medium textured and moderately mottles; single grain; friable, nonsticky
fine textured. San Anton soils are better drained than and nonplastic; common fine roots; 10
Constancia soils, percent by volume is fine volcanic rock
Sa-San Anton clay loam. This is a nearly level soil fragments; very strongly alkaline; clear
on alluvial fans in the semiarid area. It is in areas of smooth boundary.
about 50 to 200 acres. Slopes are 0 to 2 percent. Bg-9 to 14 inches; dark grayish brown (10YR
Included in mapping are some areas of soils that 4/2), dark greenish gray (5GY 4/1),
have a silty clay loam surface layer and some small and brown (10YR 4/3) sandy clay loam;
areas of the calcareous Cortada soils. weak fine and medium subangular blocky
Runoff is slow. This soil is not subject to erosion. It structure; firm, slightly sticky and plas-
can be used for intensive cropping without loss of soil tic; 10 percent by volume is fine volcanic
material. It is subject to flooding in some years, gen- rock fragments; very strongly alkaline;
erally from August to October. This soil is easy to till. clear smooth boundary.
Because rainfall is low and poorly distributed through- C-14 to 21 inches; very dark grayish brown
out the year, this soil needs to be irrigated. Long 14(2.5Y 3/2) loamvy sand; many mediumbrown
periods of drought are common in most years. (2d5Y 3/2) loamy sand; man medium
Land leveling or smoothing is feasible. The root distinct brown (10YR 4/3) and many
zone is deep. This soil is fertile, and crops respond fine distinct very dark gray (5Y 3/1)
well to fertilizer, mottles; single grain; friable, nonstick
This soil has mainly been used for sugarcane under and nonplastic; 10 percent by volume is
irrigation management. Small areas that are not ir- strongly alkaline; clear smooth bound-
rigated are in pasture. Some areas are in vegetables, ary.
mainly tomatoes. If irrigated, this soil is suited to C2-21 to 60 inches; very dark gray (5Y 3/1)
sugarcane and to a wide range of vegetables and food sand; few fine faint dark olive gray (5Y
crops. 3/2) mottles; single grain; friable, non-
Capability units 1-2, irrigated, and IIc-1, nonir- sticky and nonplastic; 10 percent by
rigated; not in a woodland suitability group. volume is fine volcanic rock fragments;







PONCE AREA OF SOUTHERN PUERTO RICO 43

water table is at 40 inches; very strongly All-0 to 6 inches; dark grayish brown (10YR
alkaline. 4/2) clay; weak fine subangular blocky
The solum is 11 to 20 inches thick. The All horizon structure; firm, slightly sticky and plas-
has hue of 10YR and 2.5Y, value of 3, and chroma of tic; many fine roots; very strongly alka-
2 or 3. The B horizon is sandy clay loam to sandy loam. line; clear smooth boundary.
Depth to the water table ranges from 30 to 42 inches. A12-6 to 15 inches; very dark grayish brown
The content of fine volcanic rock fragments is 5 to 15 (10YR 3/2) clay; moderate fine and
percent throughout the profile. medium subangular blocky structure;
Serrano soils are on the same landscape as Teresa, firm, slightly sticky and plastic; com-
Machuelo, and Meros soils. Serrano soils are coarser mon fine roots; very strongly alkaline;
textured than Teresa soils. Serrano soils are coarser clear smooth boundary.
textured throughout the profile than Machuelo soils. B-15 to 23 inches; brown (10YR 4/3) silty clay
Unlike Machuelo and Meros soils, Serrano soils are loam; few fine distinct dark gray (10YR
saline. 4/1), light gray (10YR 7/2), and black
Se-Serrano sand. This is a nearly level soil on the (10YR 2/1) mottles; weak fine and
coastal plains near the beach in the semiarid area. It medium subangular blocky structure;
generally is in areas of about 20 to 50 acres. This soil firm, slightly sticky and plastic; 5 per-
is saline throughout. It has 0 to 2 percent slopes, cent, by volume, is fine limestone frag-
Included in mapping are a few narrow strips of ments; very strongly alkaline; clear
beach sands that are reworked by the waves and a few smooth boundary.
areas of nonsaline Meros soils. C1-23 to 34 inches; dark gray (10YR 4/1) silty
Runoff is slow. Erosion is not a hazard. A large clay loam; common fine distinct yellow-
amount of harmful salts throughout the profile makes ish brown (10YR 5/6) few fine distinct
this soil not suitable for crops. The cost of reclamation black (10YR 2/1), and few fine faint
is high. Drainage is needed on this soil. gray (10YR 6/1, 5/1) mottles; massive;
In most areas this soil is barren of vegetation, and firm, slightly sticky and plastic; 10 per-
attempts to grow sugarcane have failed. cent, by volume, is fine limestone frag-
Capability unit VIIs-4; not in a woodland suit- ments; very strongly alkaline; clear
ability group. smooth boundary.
C2-34 to 44 inches; dark gray (5Y 4/1) and
Teresa series black (10YR 2/1) clay; few fine distinct
gray (10YR 6/1), and yellowish brown
The Teresa series consists of somewhat poorly (10YR 5/6) mottles; massive; firm,
drained, saline, nearly level soils on coastal plains near sticky and plastic; very strongly alka-
the beach in the semiarid area. These soils formed in line; gradual wavy boundary.
moderately fine, medium, and fine textured sediment C3-44 to 50 inches; dark gray (5Y 4/1) clay;
of mixed origin. Slopes are 0 to 2 percent. The annual common fine prominent yellowish brown
rainfall ranges from 20 to 30 inches, and the tempera- (10YR 5/6) ; few fine distinct gray
ture ranges from 780 to 800 F. (10YR 6/1) and few fine prominent
In a representative profile, the surface layer is dark black (10YR 2/1) mottles; rubbed color
grayish brown clay about 6 inches thick. The sub- is very dark grayish brown (2.5Y 3/2);
surface layer, between depths of 6 and 15 inches, is massive; firm, slightly sticky and
very dark grayish brown, firm clay. The subsoil, be- slightly plastic; very strongly alkaline;
tween depths of 15 and 23 inches, is brown, firm silty gradual, wavy boundary.
clay loam that has gray, dark gray, and black mottles. C4-50 to 60 inches; dark gray (5Y 4/1) sandy
The substratum, between depths of 23 and 34 inches, loam; few fine prominent yellowish
is dark gray, firm silty clay loam that has yellowish brown (10YR 5/6) and black (10YR
brown, black, and gray mottles; between depths of 34 2/1) mottles; single grain; friable, non-
and 44 inches, it is dark gray and black, firm clay that sticky and nonplastic; very strongly
has gray and yellowish brown mottles; between depths alkaline.
of 44 and 50 inches, it is dark gray, firm clay that has The solum is 16 to 30 inches thick. Salinity in the A
yellowish brown, gray, and black mottles; and between and B horizons ranges from 12 to 22 millimhos per
depths of 50 and 60 inches, it is dark gray, friable centimeter. The All horizon has hue of 10YR, value of
sandy loam that has yellowish brown and black 3 or 4, and chroma of 2 or 3. The B horizon has hue of
mottles. 3 or 4, and chroma of 2 or 3. The B horizon has hue of
Permeability is moderate, and the available water 10YR, value of 3 or 4, and chroma of 3. The B horizon
capacity is moderate to high. Natural fertility is very is silty clay loam to clay in texture. It is weak medium
low. The concentration of salts throughout the profile to moderate fine and medium subangular blocky in
is high. Runoff is very slow. structure. Depth to the water table ranges from 30 to
These soils have little or no agricultural value. 40 inches. Soil reaction ranges from pH 10.0 in the
Attempts to grow sugarcane on these soils have failed, upper horizons to pH 9.0 in the lower part of the C
If these soils are used for agricultural purposes, a horizon.
major reclamation project is needed. Teresa soils are on the same landscape as Serrano
Representative profile of Teresa clay, 1 kilometer and Machuelo soils. Unlike Serrano soils, which are
south of kilometer marker 116.3 on Highway 1: coarse textured and poorly drained, Teresa soils are







44 SOIL SURVEY

fine textured and somewhat poorly drained. Unlike Representative profile of Toa silty clay loam, 50
Machuelo soils, Teresa soils are saline. meters east of kilometer marker.2.0 on Highway 391:
Te-Teresa clay. This is a nearly level soil on the Ap-0 to 10 inches; very dark grayish brown
coastal plain in the semiarid area. It is adjacent to the (10YR 3/2) silty clay loam; moderate
beach in areas of about 100 to 200 acres. It is saline fine granular structure; firm, slightly
throughout. Slopes are 0 to 2 percent. sticky and plastic; many fine roots;
Included in mapping are a few areas of Serrano many fine volcanic rock fragments;
sand and Tidal flats and a very few areas of the non- slightly acid; clear smooth boundary.
saline Meros sand. B2-10 to 20 inches; dark brown (10YR 3/3)
Runoff is very slow. Erosion is not a hazard. Because clay loam; weak medium subangular
of the high content of salt throughout the profile, this blocky structure; firm, slightly sticky
soil is not suited to crops or pasture. Reclamation is and plastic; many fine roots; many fine
costly, and drainage is necessary. volcanic rock fragments; slightly acid;
This soil is mostly barren of vegetation. In a few clear smooth boundary.
areas it is in salt-tolerant weeds. Attempts to plant B3-20 to 30 inches; dark grayish brown (10YR
this soil to sugarcane have failed. This soil has no 4/2) silty clay loam; few fine faint gray
agricultural value. (10YR 6/1) mottles; weak fine subangu-
Capability unit VIs-2; not in a woodland suitability lar blocky structure; firm, slightly
group. sticky and plastic; common fine roots;
few fine volcanic rock fragments;
slightly acid; clear smooth boundary.
Tidal flats C1-30 to 42 inches; 80 percent dark grayish
brown (10YR 4/2), 20 percent dark
Tf-Tidal flats. Tidal flats are on the coastal plains brown (10YR 4/3) silty clay loam; few
in the semiarid area. They are barren, sandy areas fine faint gray (10YR 6/1) mottles;
that are periodically covered by tidal water. Some of massive firm, slightly sticky and
these areas are covered permanently by saltwater; slightly plastic; few fine roots; slightly
others are covered only during unusually high tides. acid; clear smooth boundary.
When these areas are dry, a few inches of mud covers C2-42 to 60 inches; dark brown (10YR 4/3)
the surface in places, salt accumulations are common clay loam; few yellowish red (YR 5/8)
on the surface, and in places there are thin layers of and loamfew fine faint gray (YR 6/1)
fine-textured soil material that was deposited by nearby mottles; massive; friable, slightly sticky
streams. and slightly plastic; slightly acid.
This miscellaneous area has no value for farming The solum is 22 to 36 inches thick. The Ap horizon
because of the high salt content and high water table. has hue of 10YR, value of 3, and chroma of 2 or 3. The
Reclamation is not practical. Tidal flats have severe B2 horizon has hue of 10YR, value of 4, and chroma of
limitations for nonfarm uses that are extremely 2or 3. The B2 horizon ranges from clay loam to silty
difficult to overcome.
abiit it IIIs-1; not in a woodland suit- clay loam. It is weak fine or medium subangular blocky
Capability unit VIIIs-1; not in a woodland su in structure.
ability group. Toa soils are on the same landscape as Reilly soils,
but they have a thicker profile than Reilly soils and
Toa series are finer textured throughout.
To-Toa silty clay loam. This is a nearly level soil
The Toa series consists of well drained, nearly level on flood plains in the humid area. This soil generally
soils adjacent to rivers and streams in the humid area. is in narrow strips that are about 20 to 50 acres in
These soils formed in moderately fine textured sedi- size. Slopes are 0 to 2 percent.
ment of mixed origin. Slopes are 0 to 2 percent. The Included in mapping are a few areas where this soil
annual rainfall is 60 to 80 inches, and the temperature is closer to riverbanks that have sand and gravel
is 760 to 780 F. between depths of 20 and 40 inches.
In a representative profile, the surface layer is very Runoff is slow, and erosion is not a hazard. This soil
dark grayish brown silty clay loam about 10 inches can be intensively cropped without loss of soil mate-
thick. The subsoil, between depths of 10 and 20 inches, rial. It is subject to flooding in most years, mainly
is dark brown, firm clay loam, and between depths of from June to October. This soil is easy to till. The root
20 and 30 inches it is dark grayish brown, firm silty zone is deep. Machinery can be used on this soil. This
clay loam that has gray mottles. The substratum, soil is fertile, and crops respond well to fertilizer.
between depths of 30 and 42 inches, is dark grayish This soil is used mainly for sugarcane. In some areas
brown and dark brown, firm silty clay loam that hasn pangolagrass. A small
gray mottles, and between depths of 42 and 60 inches it is in native pasture and pangolagrass. A small
it is friable clay loam that has rust and gray mottles. acreage is planted to food crops.
Permeability is moderate, and the available water This soil can be used for cultivated crops if it is
capacity is moderate to high. Natural fertility is high. managed to maintain productivity and good tilth. It is
These soils are easy to work. Runoff is slow. suited to sugarcane and to many food crops and
In most areas these soils have been in sugarcane for vegetables. Pangolagrass and stargrass grow well on
many years. In some small areas they are planted to this soil. This soil is suited to merkergrass that is
food crops, and in a few areas they are used as pasture. planted as green chop.







44 SOIL SURVEY

fine textured and somewhat poorly drained. Unlike Representative profile of Toa silty clay loam, 50
Machuelo soils, Teresa soils are saline. meters east of kilometer marker.2.0 on Highway 391:
Te-Teresa clay. This is a nearly level soil on the Ap-0 to 10 inches; very dark grayish brown
coastal plain in the semiarid area. It is adjacent to the (10YR 3/2) silty clay loam; moderate
beach in areas of about 100 to 200 acres. It is saline fine granular structure; firm, slightly
throughout. Slopes are 0 to 2 percent. sticky and plastic; many fine roots;
Included in mapping are a few areas of Serrano many fine volcanic rock fragments;
sand and Tidal flats and a very few areas of the non- slightly acid; clear smooth boundary.
saline Meros sand. B2-10 to 20 inches; dark brown (10YR 3/3)
Runoff is very slow. Erosion is not a hazard. Because clay loam; weak medium subangular
of the high content of salt throughout the profile, this blocky structure; firm, slightly sticky
soil is not suited to crops or pasture. Reclamation is and plastic; many fine roots; many fine
costly, and drainage is necessary. volcanic rock fragments; slightly acid;
This soil is mostly barren of vegetation. In a few clear smooth boundary.
areas it is in salt-tolerant weeds. Attempts to plant B3-20 to 30 inches; dark grayish brown (10YR
this soil to sugarcane have failed. This soil has no 4/2) silty clay loam; few fine faint gray
agricultural value. (10YR 6/1) mottles; weak fine subangu-
Capability unit VIs-2; not in a woodland suitability lar blocky structure; firm, slightly
group. sticky and plastic; common fine roots;
few fine volcanic rock fragments;
slightly acid; clear smooth boundary.
Tidal flats C1-30 to 42 inches; 80 percent dark grayish
brown (10YR 4/2), 20 percent dark
Tf-Tidal flats. Tidal flats are on the coastal plains brown (10YR 4/3) silty clay loam; few
in the semiarid area. They are barren, sandy areas fine faint gray (10YR 6/1) mottles;
that are periodically covered by tidal water. Some of massive firm, slightly sticky and
these areas are covered permanently by saltwater; slightly plastic; few fine roots; slightly
others are covered only during unusually high tides. acid; clear smooth boundary.
When these areas are dry, a few inches of mud covers C2-42 to 60 inches; dark brown (10YR 4/3)
the surface in places, salt accumulations are common clay loam; few yellowish red (YR 5/8)
on the surface, and in places there are thin layers of and loamfew fine faint gray (YR 6/1)
fine-textured soil material that was deposited by nearby mottles; massive; friable, slightly sticky
streams. and slightly plastic; slightly acid.
This miscellaneous area has no value for farming The solum is 22 to 36 inches thick. The Ap horizon
because of the high salt content and high water table. has hue of 10YR, value of 3, and chroma of 2 or 3. The
Reclamation is not practical. Tidal flats have severe B2 horizon has hue of 10YR, value of 4, and chroma of
limitations for nonfarm uses that are extremely 2or 3. The B2 horizon ranges from clay loam to silty
difficult to overcome.
abiit it IIIs-1; not in a woodland suit- clay loam. It is weak fine or medium subangular blocky
Capability unit VIIIs-1; not in a woodland su in structure.
ability group. Toa soils are on the same landscape as Reilly soils,
but they have a thicker profile than Reilly soils and
Toa series are finer textured throughout.
To-Toa silty clay loam. This is a nearly level soil
The Toa series consists of well drained, nearly level on flood plains in the humid area. This soil generally
soils adjacent to rivers and streams in the humid area. is in narrow strips that are about 20 to 50 acres in
These soils formed in moderately fine textured sedi- size. Slopes are 0 to 2 percent.
ment of mixed origin. Slopes are 0 to 2 percent. The Included in mapping are a few areas where this soil
annual rainfall is 60 to 80 inches, and the temperature is closer to riverbanks that have sand and gravel
is 760 to 780 F. between depths of 20 and 40 inches.
In a representative profile, the surface layer is very Runoff is slow, and erosion is not a hazard. This soil
dark grayish brown silty clay loam about 10 inches can be intensively cropped without loss of soil mate-
thick. The subsoil, between depths of 10 and 20 inches, rial. It is subject to flooding in most years, mainly
is dark brown, firm clay loam, and between depths of from June to October. This soil is easy to till. The root
20 and 30 inches it is dark grayish brown, firm silty zone is deep. Machinery can be used on this soil. This
clay loam that has gray mottles. The substratum, soil is fertile, and crops respond well to fertilizer.
between depths of 30 and 42 inches, is dark grayish This soil is used mainly for sugarcane. In some areas
brown and dark brown, firm silty clay loam that hasn pangolagrass. A small
gray mottles, and between depths of 42 and 60 inches it is in native pasture and pangolagrass. A small
it is friable clay loam that has rust and gray mottles. acreage is planted to food crops.
Permeability is moderate, and the available water This soil can be used for cultivated crops if it is
capacity is moderate to high. Natural fertility is high. managed to maintain productivity and good tilth. It is
These soils are easy to work. Runoff is slow. suited to sugarcane and to many food crops and
In most areas these soils have been in sugarcane for vegetables. Pangolagrass and stargrass grow well on
many years. In some small areas they are planted to this soil. This soil is suited to merkergrass that is
food crops, and in a few areas they are used as pasture. planted as green chop.








PONCE AREA OF SOUTHERN PUERTO RICO 45

Capability unit I-1; not in a woodland suitability slopes, side slopes, and hilltops on limestone uplands.
group. The areas generally are more than 500 acres in size.
Cobbles and outcrops of hard limestone on the surface
Tuque series are common.
Included in mapping are small areas of Aguilita
The Tuque series consists of well drained, calcare- soils. Also included are strips along drainageways that
ous, moderately steep to very steep stony soils on side consist of undifferentiated soils that vary in color and
slopes, foot slopes, and hilltops on the semiarid up- depth and a few areas of soils that do not have stones
lands. These soils are shallow and very shallow to on the surface.
indurated caliche. They formed in fine textured resid- Runoff is rapid to very rapid. Erosion is a hazard.
uum over gravelly, partly indurated limestone. Slopes This soil is not suitable for cultivation because of very
are 12 to 60 percent. The annual rainfall is 20 to 30 steep slopes and the large amount of stones on the
inches, and the temperature is 780 to 800 F. surface. The root zone is restricted by the indurated
In a representative profile, the surface layer is dark caliche. Workability is poor. Long periods of drought
reddish brown stony clay loam about 5 inches thick. are common in most years. There are very few adapted
The subsoil, between depths of 5 and 11 inches, is species of grasses and trees on this soil because of low
dark red, firm gravelly clay. The substratum, between rainfall and the high content of calcium carbonate.
depths of 11 and 19 inches, is very pale brown in- Seeding and fertilizing are not practical. The layout,
durated caliche; between depths of 19 and 24 inches, construction, and maintenance of ditches are difficult
it is strong brown, firm gravelly clay; and between and costly.
depths of 24 and 60 inches, it is gravelly limestone Most of the acreage is in brush. Clearing this brushy
that can be penetrated using a spade. land for use as pasture is costly. In a few areas,
Permeability is very slow, and the available water however, this soil is used as native pasture.
capacity is low. Natural fertility is low. These soils This soil is not suitable for cultivation because of
are very difficult to work. The root zone is restricted, slope, the erosion hazard, and the large amount of
Runoff is rapid to very rapid. stones on the surface. It should be maintained in
In most areas these soils have been in brush for permanent vegetation to control erosion.
many years, and in some areas they are used as brushy Capability unit VIIs-2; not in a woodland suitabil-
pasture. ity group.
Representative profile of Tuque stony clay loam, 12
to 60 percent slopes, 500 meters north of kilometer Yauco series
marker 254.8 on Highway 2:
A1-0 to 5 inches; dark reddish brown (2.5YR The Yauco series consists of well drained, calcare-
3/4) stony clay loam; weak fine granular ous, gently sloping and strongly sloping soils on
structure; friable, slightly sticky and rounded hills and foot slopes below the limestone hills
plastic; many fine and medium roots; in the semiarid area. Slope ranges from 2 to 12 per-
many shell fragments; violent efferves- cent. These soils formed in transported moderately
cence; clear broken boundary. fine textured sediment that was derived from lime-
B2-5 to 11 inches; dark red (2.5YR 3/6) grav- stone. The annual rainfall is 25 to 40 inches, and the
elly clay; weak fine and medium sub- temperature is 780 to 800 F.
angular blocky parting to weak fine In a representative profile, the surface layer is very
granular structure; firm, slightly sticky dark grayish brown silty clay loam about 11 inches
and plastic; violent effervescence; clear thick. The subsoil, between depths of 11 and 17 inches,
broken boundary. is dark brown and very dark grayish brown, firm
Clcam-11 to 19 inches; very pale brown (10YR silty clay loam; and between depths of 17 and 21
8/3) indurated caliche; laminar, with inches, it is yellowish brown and light yellowish
brownish horizontal bands; gradual bro- brown, firm silty clay loam. The substratum, between
ken boundary. depths of 21 and 60 inches, is very pale brown soft
C2-19 to 24 inches; strong brown (7.5YR 5/6) limestone that can be easily penetrated using a spade
gravelly clay; massive; firm, slightly or an auger.
sticky and plastic; violent effervescence; Permeability is moderate, and the available water
gradual wavy boundary. capacity is low to. moderate. Natural fertility is high,
C3-24 to 60 inches; gravelly limestone that can and the content of organic matter in the surface layer
be penetrated using a spade or an auger. generally is high. The root zone is restricted because
Thickness of the solum and depth to caliche range of the high content of calcium carbonate.
from 8 to 14 inches. The caliche horizon is 4 to 8 Yauco soils have been used mainly as native pasture.
inches thick. Gravelly limestone is at a depth between In some areas, they have been planted to sugarcane.
16 and 30 inches. The soil material is 35 to 50 percent Representative profile of Yauco silty clay loam, 2 to
limestone fragments throughout. The surface is 25 to 5 percent slopes, 2.4 kilometers west of kilometer
40 percent rocks, marker 3.05 on Highway 510:
Tuque soils are on the same landscape as Aguilita Ap-0 to 11 inches; very dark grayish brown
soils. Unlike Aguilita soils, Tuque soils have a caliche (10YR 3/2) silty clay loam; strong fine
horizon. Tuque soils are redder than Aguilita soils, and medium granular structure; firm,
TuF-Tuque stony clay loam, 12 to 60 percent slopes, slightly sticky and plastic; many fine
This is a moderately steep to very steep soil on foot roots; common fine shell, volcanic rock,








PONCE AREA OF SOUTHERN PUERTO RICO 45

Capability unit I-1; not in a woodland suitability slopes, side slopes, and hilltops on limestone uplands.
group. The areas generally are more than 500 acres in size.
Cobbles and outcrops of hard limestone on the surface
Tuque series are common.
Included in mapping are small areas of Aguilita
The Tuque series consists of well drained, calcare- soils. Also included are strips along drainageways that
ous, moderately steep to very steep stony soils on side consist of undifferentiated soils that vary in color and
slopes, foot slopes, and hilltops on the semiarid up- depth and a few areas of soils that do not have stones
lands. These soils are shallow and very shallow to on the surface.
indurated caliche. They formed in fine textured resid- Runoff is rapid to very rapid. Erosion is a hazard.
uum over gravelly, partly indurated limestone. Slopes This soil is not suitable for cultivation because of very
are 12 to 60 percent. The annual rainfall is 20 to 30 steep slopes and the large amount of stones on the
inches, and the temperature is 780 to 800 F. surface. The root zone is restricted by the indurated
In a representative profile, the surface layer is dark caliche. Workability is poor. Long periods of drought
reddish brown stony clay loam about 5 inches thick. are common in most years. There are very few adapted
The subsoil, between depths of 5 and 11 inches, is species of grasses and trees on this soil because of low
dark red, firm gravelly clay. The substratum, between rainfall and the high content of calcium carbonate.
depths of 11 and 19 inches, is very pale brown in- Seeding and fertilizing are not practical. The layout,
durated caliche; between depths of 19 and 24 inches, construction, and maintenance of ditches are difficult
it is strong brown, firm gravelly clay; and between and costly.
depths of 24 and 60 inches, it is gravelly limestone Most of the acreage is in brush. Clearing this brushy
that can be penetrated using a spade. land for use as pasture is costly. In a few areas,
Permeability is very slow, and the available water however, this soil is used as native pasture.
capacity is low. Natural fertility is low. These soils This soil is not suitable for cultivation because of
are very difficult to work. The root zone is restricted, slope, the erosion hazard, and the large amount of
Runoff is rapid to very rapid. stones on the surface. It should be maintained in
In most areas these soils have been in brush for permanent vegetation to control erosion.
many years, and in some areas they are used as brushy Capability unit VIIs-2; not in a woodland suitabil-
pasture. ity group.
Representative profile of Tuque stony clay loam, 12
to 60 percent slopes, 500 meters north of kilometer Yauco series
marker 254.8 on Highway 2:
A1-0 to 5 inches; dark reddish brown (2.5YR The Yauco series consists of well drained, calcare-
3/4) stony clay loam; weak fine granular ous, gently sloping and strongly sloping soils on
structure; friable, slightly sticky and rounded hills and foot slopes below the limestone hills
plastic; many fine and medium roots; in the semiarid area. Slope ranges from 2 to 12 per-
many shell fragments; violent efferves- cent. These soils formed in transported moderately
cence; clear broken boundary. fine textured sediment that was derived from lime-
B2-5 to 11 inches; dark red (2.5YR 3/6) grav- stone. The annual rainfall is 25 to 40 inches, and the
elly clay; weak fine and medium sub- temperature is 780 to 800 F.
angular blocky parting to weak fine In a representative profile, the surface layer is very
granular structure; firm, slightly sticky dark grayish brown silty clay loam about 11 inches
and plastic; violent effervescence; clear thick. The subsoil, between depths of 11 and 17 inches,
broken boundary. is dark brown and very dark grayish brown, firm
Clcam-11 to 19 inches; very pale brown (10YR silty clay loam; and between depths of 17 and 21
8/3) indurated caliche; laminar, with inches, it is yellowish brown and light yellowish
brownish horizontal bands; gradual bro- brown, firm silty clay loam. The substratum, between
ken boundary. depths of 21 and 60 inches, is very pale brown soft
C2-19 to 24 inches; strong brown (7.5YR 5/6) limestone that can be easily penetrated using a spade
gravelly clay; massive; firm, slightly or an auger.
sticky and plastic; violent effervescence; Permeability is moderate, and the available water
gradual wavy boundary. capacity is low to. moderate. Natural fertility is high,
C3-24 to 60 inches; gravelly limestone that can and the content of organic matter in the surface layer
be penetrated using a spade or an auger. generally is high. The root zone is restricted because
Thickness of the solum and depth to caliche range of the high content of calcium carbonate.
from 8 to 14 inches. The caliche horizon is 4 to 8 Yauco soils have been used mainly as native pasture.
inches thick. Gravelly limestone is at a depth between In some areas, they have been planted to sugarcane.
16 and 30 inches. The soil material is 35 to 50 percent Representative profile of Yauco silty clay loam, 2 to
limestone fragments throughout. The surface is 25 to 5 percent slopes, 2.4 kilometers west of kilometer
40 percent rocks, marker 3.05 on Highway 510:
Tuque soils are on the same landscape as Aguilita Ap-0 to 11 inches; very dark grayish brown
soils. Unlike Aguilita soils, Tuque soils have a caliche (10YR 3/2) silty clay loam; strong fine
horizon. Tuque soils are redder than Aguilita soils, and medium granular structure; firm,
TuF-Tuque stony clay loam, 12 to 60 percent slopes, slightly sticky and plastic; many fine
This is a moderately steep to very steep soil on foot roots; common fine shell, volcanic rock,







46 SOIL SURVEY

and limestone fragments; strong effer- Capability units IIIe-4, irrigated, and IVc-3, non-
vescence; clear smooth boundary. irrigated; woodland suitability group 2ol.
B2ca-11 to 17 inches; 80 percent dark brown YcC-Yauco silty clay loam, 5 to 12 percent slopes.
(10YR 4/3),.20 percent very dark gray- This is a strongly sloping soil on small rounded hills
ish brown (10YR 3/2) silty clay loam; and foot slopes below the limestone hills. The areas
moderate fine and medium subangular generally are about 20 to 50 acres in size. This soil is
'blocky structure; firm, slightly sticky similar to the one described as representative of the
and plastic; few fine roots; common fine series, except it has a slightly thinner surface and
shell fragments; many fine calcium car- subsoil.
bonate accumulations in the form of Included in mapping are many small areas of soils
mycelia and pendents; violent efferves- that have soft limestone at or near the surface and
cence; clear smooth boundary. other small areas where the surface is 10 to 15 percent
B3ca-17 to 21 inches; 50 percent yellowish limestone cobbles and rocks.
brown (10YR 5/4) and 50 percent light Runoff is medium. Erosion is a hazard. Cultivated
yellowish brown (10YR 6/4) silty clay crops can be planted periodically, but if they are
loam; weak fine subangular blocky grown, erosion needs to be controlled. The choice of
structure; firm, slightly sticky and plas- food crops and pasture grasses is limited because of
tic; violent effervescence; many calcium the low, poorly distributed rainfall and because of the
carbonate accumulations in the form of high content of carbonates below the surface layer.
mycelia and pendents; clear wavy Shallow plowing is helpful. The root zone is restricted
boundary, by carbonates. The use of this soil for food crops is
C-21 to 60 inches; very pale brown (10YR 7/3) restricted mainly to the rainy months in favorable
soft limestone that can be easily pene- years.
treated using a spade or an auger. This soil generally is used as pasture. It can be used
The thickness of the solum and the depth to soft for food crops such as corn and pigeonpeas, but its
limestone range from 20 to 30 inches. The Ap horizon use for crops is restricted to the rainy months from
has hue of 10YR and value and chroma of 3 or less. May to October because water is not available at other
The upper part of the B horizon has hue of 10YR, times. A very few acres are planted to sugarcane under
value of 3 and 4, and chroma of 2 and 3. The lower furrow irrigation. Sprinkler irrigation can be used to
part of the B horizon has hue of 10YR and value and control erosion if irrigation water is available. Guinea-
chroma of 4 or higher. The B horizon is weak to grass and Angletongrass are the best adapted grasses.
moderate and fine to medium subangular blocky in Capability units IIIe-4, irrigated, and IVc-3, non-
structure. irrigated; woodland suitability group 2ol.
Yauco soils are on the same landscape as Aguilita
and Tuque soils. Yauco soils are deeper to soft lime-
stone than Aguilita soils and do not have gravel Use and management of the soils
throughout the profile. Unlike Tuque soils, Yauco soils
do not have indurated limestone. This section explains the system of capability
YcB-Yauco silty clay loam, 2 to 5 percent slopes, classification used by the Soil Conservation Service
This is a gently sloping soil on foot slopes in the and gives the estimated yields of the principal crops
semiarid area. This soil generally is below the lime- and pasture grasses grown in the Ponce Area. It also
stone hills, and the areas are about 20 to 50 acres in contains information on the use and management of
size. This is the soil described as representative of the the soils in the survey area for woodland, for recrea-
series, tion, and for engineering uses.
Included in mapping are a few areas of soils that
have about 10 to 15 percent cobbles on the surface and Crops and pasture
some narrow strips of soils that are deeper to soft
limestone than this Yauco soil. Some principles of management are general enough
Runoff is slow. Erosion is a hazard, and it needs to to apply to all the soils suited to crops and pasture in
be controlled if cultivated crops are grown. Land the survey area, though the individual soils or groups
leveling or smoothing can expose the soft limestone of soils require different kinds of management. These
at the surface. Irrigation is needed on this soil because general principles of management are discussed in the
of low, poorly distributed rainfall. Long periods of following paragraphs. Use and management for each
drought are common in most years from December to soil are discussed in the section "Description of the
r. soils."
April. Many soils in this survey area need lime or fertilizer,
The root zone is somewhat restricted by the high or both. The amount needed depends on the natural
content of carbonates below the surface layer. Few content of lime and plant nutrients, which is deter-
food crops and grasses can adapt to this soil because mined by laboratory analyses of soil samples; on the
of low rainfall and the high content of carbonates. needs of the crop; and on the desired level of yields.
Most of the acreage is used as native pasture be- Only general suggestions for applying lime and fer-
cause water for irrigation is not available. In areas tilizer are given in this publication.
that are irrigated this soil is in sugarcane, which is Tillage tends to break down structure, therefore it
the best adapted crop. Guineagrass and Angletongrass should be kept to the minimum necessary to prepare
are among the best adapted grasses, the seedbed and control weeds. Maintaining the organic







46 SOIL SURVEY

and limestone fragments; strong effer- Capability units IIIe-4, irrigated, and IVc-3, non-
vescence; clear smooth boundary. irrigated; woodland suitability group 2ol.
B2ca-11 to 17 inches; 80 percent dark brown YcC-Yauco silty clay loam, 5 to 12 percent slopes.
(10YR 4/3),.20 percent very dark gray- This is a strongly sloping soil on small rounded hills
ish brown (10YR 3/2) silty clay loam; and foot slopes below the limestone hills. The areas
moderate fine and medium subangular generally are about 20 to 50 acres in size. This soil is
'blocky structure; firm, slightly sticky similar to the one described as representative of the
and plastic; few fine roots; common fine series, except it has a slightly thinner surface and
shell fragments; many fine calcium car- subsoil.
bonate accumulations in the form of Included in mapping are many small areas of soils
mycelia and pendents; violent efferves- that have soft limestone at or near the surface and
cence; clear smooth boundary. other small areas where the surface is 10 to 15 percent
B3ca-17 to 21 inches; 50 percent yellowish limestone cobbles and rocks.
brown (10YR 5/4) and 50 percent light Runoff is medium. Erosion is a hazard. Cultivated
yellowish brown (10YR 6/4) silty clay crops can be planted periodically, but if they are
loam; weak fine subangular blocky grown, erosion needs to be controlled. The choice of
structure; firm, slightly sticky and plas- food crops and pasture grasses is limited because of
tic; violent effervescence; many calcium the low, poorly distributed rainfall and because of the
carbonate accumulations in the form of high content of carbonates below the surface layer.
mycelia and pendents; clear wavy Shallow plowing is helpful. The root zone is restricted
boundary, by carbonates. The use of this soil for food crops is
C-21 to 60 inches; very pale brown (10YR 7/3) restricted mainly to the rainy months in favorable
soft limestone that can be easily pene- years.
treated using a spade or an auger. This soil generally is used as pasture. It can be used
The thickness of the solum and the depth to soft for food crops such as corn and pigeonpeas, but its
limestone range from 20 to 30 inches. The Ap horizon use for crops is restricted to the rainy months from
has hue of 10YR and value and chroma of 3 or less. May to October because water is not available at other
The upper part of the B horizon has hue of 10YR, times. A very few acres are planted to sugarcane under
value of 3 and 4, and chroma of 2 and 3. The lower furrow irrigation. Sprinkler irrigation can be used to
part of the B horizon has hue of 10YR and value and control erosion if irrigation water is available. Guinea-
chroma of 4 or higher. The B horizon is weak to grass and Angletongrass are the best adapted grasses.
moderate and fine to medium subangular blocky in Capability units IIIe-4, irrigated, and IVc-3, non-
structure. irrigated; woodland suitability group 2ol.
Yauco soils are on the same landscape as Aguilita
and Tuque soils. Yauco soils are deeper to soft lime-
stone than Aguilita soils and do not have gravel Use and management of the soils
throughout the profile. Unlike Tuque soils, Yauco soils
do not have indurated limestone. This section explains the system of capability
YcB-Yauco silty clay loam, 2 to 5 percent slopes, classification used by the Soil Conservation Service
This is a gently sloping soil on foot slopes in the and gives the estimated yields of the principal crops
semiarid area. This soil generally is below the lime- and pasture grasses grown in the Ponce Area. It also
stone hills, and the areas are about 20 to 50 acres in contains information on the use and management of
size. This is the soil described as representative of the the soils in the survey area for woodland, for recrea-
series, tion, and for engineering uses.
Included in mapping are a few areas of soils that
have about 10 to 15 percent cobbles on the surface and Crops and pasture
some narrow strips of soils that are deeper to soft
limestone than this Yauco soil. Some principles of management are general enough
Runoff is slow. Erosion is a hazard, and it needs to to apply to all the soils suited to crops and pasture in
be controlled if cultivated crops are grown. Land the survey area, though the individual soils or groups
leveling or smoothing can expose the soft limestone of soils require different kinds of management. These
at the surface. Irrigation is needed on this soil because general principles of management are discussed in the
of low, poorly distributed rainfall. Long periods of following paragraphs. Use and management for each
drought are common in most years from December to soil are discussed in the section "Description of the
r. soils."
April. Many soils in this survey area need lime or fertilizer,
The root zone is somewhat restricted by the high or both. The amount needed depends on the natural
content of carbonates below the surface layer. Few content of lime and plant nutrients, which is deter-
food crops and grasses can adapt to this soil because mined by laboratory analyses of soil samples; on the
of low rainfall and the high content of carbonates. needs of the crop; and on the desired level of yields.
Most of the acreage is used as native pasture be- Only general suggestions for applying lime and fer-
cause water for irrigation is not available. In areas tilizer are given in this publication.
that are irrigated this soil is in sugarcane, which is Tillage tends to break down structure, therefore it
the best adapted crop. Guineagrass and Angletongrass should be kept to the minimum necessary to prepare
are among the best adapted grasses, the seedbed and control weeds. Maintaining the organic







PONCE AREA OF SOUTHERN PUERTO RICO 47

matter content of the plow layer helps to preserve soil class, and the unit. These are discussed in the follow-
structure. The organic matter content of the plow ing paragraphs.
layer can be maintained by adding manure, by leaving CAPABILITY CLASSES, the broadest groups, are desig-
crop residue on the surface, and by growing cover nated by Roman numerals I through VIII. The nu-
crops and green manure crops, merals indicate progressively greater limitations and
On wet soils, such as Machuelo clay and Cintrona narrower choices for practical use.
clay, the yield of sugarcane can be increased by using CAPABILITY SUBCLASSES are soil groups within one
a drainage system of open ditches and suitable outlets. class; they are designated by adding a small letter,
All of the gently sloping and steeper soils that are e, w, s, or c, to the class numeral, for example, IIe. The
cultivated are subject to erosion. Runoff and erosion letter e shows that the main limitation is risk of ero-
occur mostly while a cultivated crop is growing or soon sion unless close-growing plant cover is maintained;
after one has been harvested. On all erodible soils, a w shows that water in or on the soil interferes with
cropping system that controls runoff and erosion needs plant growth or cultivation (in some soils the wetness
to be combined with other erosion control practices. can be partly corrected by artificial drainage) ; s shows
As used here, cropping system refers to the sequence that the soil is limited mainly because it is shallow,
of crops grown and should be combined with manage- drought, or stony; and c, used in only some parts of
ment that includes minimum tillage, using crop resi- the United States, shows that the chief limitation is
due, growing cover crops, and applying lime and fer- climate that is too cold or too dry.
tilizer. Other erosion control practices are contour In class I there are no subclasses, because the soils
cultivation, terracing, contour stripcropping, diversion of this class have few limitations. Class V contains
of runoff, and use of grassed waterways. The effective- only the subclasses indicated by w, s, and c, because
ness of a particular combination of these measures the soils in class V are subject to little or no erosion,
differs from one soil to another, but different com- though they have other limitations that restrict their
binations can be equally effective on the same soil. use largely to pasture, range, woodland, wildlife hab-
The local representative of the Soil Conservation Ser- itat, or recreation.
vice can assist in planning an effective combination of CAPABILITY UNITS are soil groups within the sub-
practices. classes. The soils in one capability unit are enough
Pasture is effective in controlling erosion on all but alike to be suited to the same crops and pasture plants,
a few of the soils. A high level of pasture management to require similar management, and to have similar
is needed to provide enough ground cover to keep the productivity and other responses to management.
soil from eroding, especially on the semiarid uplands Thus, the capability unit is a convenient grouping for
that are subject to long periods of drought. A high making many statements about management of soils.
level of pasture management calls for fertilization, Capability units are generally designated by adding an
control of grazing, selection of pasture mixtures, con- Arabic numeral to the subclass symbol, for example,
trolled rate of stocking, and other practices that help Ile-4 or IIIe-6. Thus, in one symbol, the Roman nu-
maintain good ground cover and forage plants. Grazing meral designates the capability class, or degree of
is controlled by rotating the livestock from one pasture limitation; the small letter indicates the subclass, or
to another and resting the pasture after each grazing kind of limitation; and the Arabic numeral specifically
period to allow for regrowth of the plants. On some identifies the capability unit within each subclass.
soils, pasture mixtures should be selected that require The eight classes in the capability system and the
the least amount of renovation to provide good ground subclasses and units in the Ponce Area are described in
cover and forage for grazing. the list that follows.
Class I: Soils have few limitations that restrict their
Capability grouping use.
(No subclasses).
Capability grouping shows, in a general way, the Capability unit I-1. Nearly level, deep, well
suitability of soils for most kinds of field crops. The drained, slightly acid, moderately permeable
soils are grouped according to their limitations when soils that have a silty clay loam surface layer.
used for field crops, the risk of damage when they are Capability unit 1-2. Nearly level, deep, well
used, and the way they respond to treatment. The drained, neutral to moderately alkaline, moder-
grouping does not take into account major and gener- ately permeable soils that have a clay loam sur-
ally expensive landforming that would change slope, face layer. In the dry area; under irrigation.
depth, or other characteristics of the soils; does not Capability unit 1-3. Nearly level, deep, well
take into consideration possible but unlikely major drained, calcareous, moderately permeable soils
reclamation projects; and does not apply to rice, cran- that have a silty clay loam surface layer. In the
berries, horticultural crops, or other crops requiring dry area; under irrigation.
special management. Class II: Soils have moderate limitations that reduce
Those familiar with the capability classification can the choice of plants or that require moderate conserva-
infer from it much about the behavior of soils when tion practices.
used for other purposes, but this classification is not a Subclass IIw: Soils moderately limited because of
substitute for interpretations designed to show suit- excess water.
ability and limitations of groups of soils for use as Capability unit IIw-1. Nearly level, deep, some-
range, for forest trees, or for engineering uses. what poorly drained, calcareous, slowly perme-
In the capability system, the kinds of soil are able soils that have a silty clay surface layer.
grouped at three levels: the capability class, the sub- In the dry area; under irrigation.








48 SOIL SURVEY

Capability unit IIw-2. Nearly level to strongly Subclass IIIc: Soils limited by deficiency of mois-
sloping, deep, moderately well drained, medium ture which results from low rainfall and a high
acid, moderately slow permeable soils that have evaporation rate.
a clay surface layer. Capability unit IIIc-1. Gently sloping, moder-
Subclass IIs: Soils moderately limited because of ately deep to gravel and sand, moderately well
poor workability, drained, neutral to moderately alkaline, slowly
Capability unit IIs-1. Gently sloping, deep, mod- permeable soils that have a clay surface layer.
erately well drained, neutral to moderately al- Not irrigated.
kaline, slowly permeable soils that have a clay Capability unit IIIc-2. Nearly level, deep, some-
surface layer. In the dry area; under irrigation, what poorly drained, calcareous, slowly perme-
Capability unit IIs-2. Gently sloping, mod- able soils that have a silty clay surface layer.
erately deep to gravel and sand, moderately well Not irrigated.
drained, neutral, slowly permeable soils that Class IV: Soils have very severe limitations that re-
have a clay surface layer. In the dry area; un- duce the choice of plants or that require very careful
der irrigation, management, or both.
Capability unit IIs-3. Gently sloping, deep, well Subclass IVe: Soils subject to very severe erosion
drained, neutral, moderately slowly per- if they are cultivated and not protected.
meable soils that have a clay surface layer. In Capability unit IVe-1. Steep, deep, well drained,
the dry area; under irrigation, very strongly acid, moderately permeable soils
Subclass IIc: Soils limited by deficiency of mois- that have a clay surface layer.
ture due to low rainfall and high evaporation rate. Capability unit IVe-2. Moderately steep, deep
Capability unit IIc-1. Nearly level, deep, well and moderately deep to volcanic rock, well
drained, neutral or calcareous, moderately per- drained, slightly acid and medium acid, mod-
meable soils that have a clay loam surface layer, erately permeable soils that have a surface
In the dry area; not irrigated, layer of silty clay or silty clay loam.
Class III: Soils have severe limitations that reduce Capability unit IVe-3. Moderately steep, moder-
the choice of plants or that require special conservation ately deep to volcanic rock, well drained,
practices, or both. slightly acid, moderately permeable soils that
Subclass IIIe: Soils subject to severe erosion if have a silty clay loam surface layer. In the dry
they are cultivated and not protected. area.
Capability unit IIIe-1. Strongly sloping and Subclass IVs: Soils very severely limited by
moderately steep, deep, well drained and mod- droughtiness.
erately well drained, strongly acid, moderately Capability unit IVs-1. Nearly level, very shallow
permeable soils that have a clay surface layer. to sand and gravel, excessively drained, medium
Capability unit IIIe-2. Strongly sloping, deep, acid, rapidly permeable soils that have a gray-
moderately well drained, neutral to moderately elly loam surface layer.
alkaline, slowly permeable soils that have a clay Subclass IVc: Soils limited by deficiency of mois-
surface layer. In the dry area; under irrigation. ture which results from low rainfall and a high
Capability unit IIIe-3. Strongly sloping, moder- evaporation rate.
ately deep to volcanic rock, well drained, mildly Capability unit IVc-1. Strongly sloping, deep,
alkaline, moderately slowly permeable soils that moderately well drained, neutral to moderately
have a clay surface layer. In the dry area; un- alkaline, slowly permeable soils that have a clay
der. irrigation, surface layer. Not irrigated.
Capability unit IIIe-4. Gently sloping to Capability unit IVc-2. Nearly level, deep, poorly
strongly sloping, moderately deep to soft lime- drained, calcareous, slowly permeable soils that
stone, well drained, calcareous, moderately per- have a clay surface layer. Not irrigated.
meable soils that have a silty clay loam surface Capability unit IVc-3. Gently sloping to
layer. In the dry area; under irrigation, strongly sloping, moderately deep to soft lime-
Capability unit IIIe-5. Strongly sloping, deep, stone, well drained, calcareous, moderately per-
well drained, neutral, moderately slowly perme- meable soils that have a silty clay loam surface
able soils that have a clay surface layer. In the layer. Not irrigated.
dry area; under irrigation. Capability unit IVc-4. Nearly level, shallow to
Subclass IIIw: Soils severely limited for cultiva- sand and gravel, somewhat excessively drained,
tion because of excess water, neutral to mildly alkaline, rapidly permeable
Capability unit IIIw-1. Nearly level, deep, poorly soils that have a silty clay loam surface layer.
drained, calcareous, slowly permeable soils that Not irrigated.
have a clay surface layer. In the dry area; un- Capability unit IVc-5. Gently sloping to
der irrigation, strongly sloping, deep, well drained, calcareous,
Subclass IIIs: Soils severely limited for cultivation moderately permeable soils that are gravelly
by droughtiness. clay throughout. Not irrigated.
Capability unit IIIs-1. Nearly level, shallow to Class V: Soils are not likely to erode but have other
sand and gravel, somewhat excessively drained, limitations, impractical to remove, that limit their use
neutral to mildly alkaline, rapidly permeable mainly to pasture, woodland, or wildlife. (None in the
soils that have a silty clay loam surface layer. Ponce Area.)
In the dry area; under irrigation. Class VI: Soils have severe limitations that make








PONCE AREA OF SOUTHERN PUERTO RICO 49

them generally unsuited to cultivation and limit their Capability unit VIIe-5. Very steep, deep, some-
use largely to pasture, woodland, or wildlife habitat. what excessively drained, strongly acid, mod-
Subclass VIe: Soils severely limited, mainly by erately rapidly permeable soils that have a clay
risk of erosion, unless protective cover is main- loam surface layer. In the humid area.
trained. Subclass VIIs: Soils severely limited by droughti-
Capability unit VIe-1. Moderately steep to very ness, stones, shallowness, or other soil features.
steep, deep, well drained and moderately well Capability unit VIIs-1. Nearly level, deep, ex-
drained, very strongly acid, moderately perme- cessively drained, neutral, very rapidly perme-
able soils that have a clay surface layer. In the able sands. In the dry area.
humid area. Capability unit VIIs-2. Moderately steep to very
Capability unit VIe-2. Moderately steep, shallow steep, shallow to limestone, well drained, cal-
to gravelly soft limestone, well drained, cal- careous, moderately permeable soils that have a
careous, moderately permeable soils that have stony clay loam surface layer. In the dry area.
a gravelly clay loam surface layer. In the dry Capability unit VIIs-3. Steep and very steep,
area. shallow and very shallow, well drained, neutral,
Capability unit VIe-3. Steep, deep and moder- moderately permeable soils that have a gravelly
ately deep to volcanic rock, well drained, clay loam surface layer. In the humid area.
slightly acid and medium acid, moderately per- Some of these soils have rocks on the surface.
meable soils that have a surface layer of clay Capability unit VIIs-4. Nearly level, deep,
loam, silty clay, or silty clay loam. In the humid poorly drained, saline, rapidly permeable soils
area. that have a sand surface layer. In the dry area.
Capability unit VIe-4. Moderately steep and Capability unit VIIs-5. Steep and very steep,
steep, moderately deep and shallow to volcanic deep and moderately deep, well drained and
rock, well drained, slightly acid to neutral, mod- moderately well drained, very strongly acid,
erately permeable soils that have a surface moderately permeable soils that have rocks on
layer of silty clay loam or clay loam. In the dry the surface. In area of high rainfall.
area. Class VIII: Soils and landforms have limitations
Subclass VIs: Soils generally unsuitable for culti- that preclude their use for commercial crop production
vation and limited for other uses by their low avail- and restrict their use to recreation, wildlife habitat,
able water capacity and high content of salts. water supply, or esthetic purposes.
Capability unit VIs-1. Nearly level to gently Subclass VIIIw: Extremely wet marshy land.
sloping, shallow to sand and gravel, excessively Capability unit VIIIw-1. Ponded areas; fresh
drained, neutral, rapidly permeable soils that water is on or near the surface throughout the
have a loam surface layer. In the dry area. year.
Capability unit VIs-2. Nearly level, deep, some- Subclass VIIIs: Coastal areas and other areas that
what poorly drained, saline, moderately perme- have little potential for commercial crop production.
able and slowly permeable soils that have a clay Capability unit VIIIs-1. Tidal flats and other
surface layer. In the dry area. saline areas.
Class VII: Soils have very severe limitations that Capability unit VIIIs-2. Riverwash.
make them unsuitable for cultivation and restrict their
use mainly to grazing, woodland, or wildlife habitat. Estimated yields
Subclass VIIe: Soils very severely limited, mainly
by risk of erosion, unless protective cover is main- Estimated average yields per acre of the principal
tainted. crops grown in the survey area under two levels of
Capability unit VIIe-1. Steep and very steep, management are given in table 3. The estimated yields
deep, well drained and moderately well drained, of the principal pasture grasses are given in table 4.
very strongly acid, moderately permeable soils In both tables, the estimated yields in the A columns
that have a clay or clay loam surface layer. In are those that can be expected under management corn-
the humid area. only used in the survey area. Under such manage-
Capability unit VIIe-2. Very steep, deep and ment, not enough lime or fertilizer is used; erosion
moderately deep to volcanic rock, well drained, control, drainage, and irrigation are inadequate; im-
slightly acid and medium acid, moderately per- proved varieties of crops are not used; seedbeds are
meable soils that have a clay loam or silty clay improperly prepared; weeds, insects, and plant dis-
loam surface layer. In the humid area. eases and runoff and erosion are not properly con-
Capability unit VIIe-3. Steep and very steep, trolled; and pastures are overgrazed.
deep, shallow, and moderately deep to volcanic The estimated yields in the B columns are those that
rock; well drained; slightly acid or calcareous; can be expected under high level management. High
moderately permeable soils that have a surface level management for cultivated crops and pasture is
layer of silty clay loam, clay loam, or clay. In defined as follows:
the dry area. 1. Surface and internal drainage provide opti-
Capability unit VIIe-4. Steep to very steep, mum growing conditions if natural drainage is
shallow to gravelly soft limestone, well drained, restricted.
calcareous, moderately permeable soils that 2. Fertilizer and lime are applied according to
have a gravelly clay loam surface layer. In the crop needs based on soil tests.
dry area. 3. All crop residue is returned to the soil.








50 SOIL SURVEY

TABLE 3.-Estimated average yields per acre of
[Yields in the A columns are those expected under common management; yields in the B columns are those expected under high
arable soils

Sugarcane Coffee

Soil Fall Spring Ratoons Shade Sun


A B A B A B A B A B

Tons Tons Tons Tons Tons Tons Cwt Cwt Cwt Cwt

Alonso clay, 20 to 40 percent slopes,
eroded-----------
Alonso clay, 40 to 60 percent slopes, 6 18
eroded ----------------------- ----------------------------------------10
Callabo silty clay loam, 12 to 20 per- --- --- --
cent slopes ----___________
Cintrona clay --------------------- 50 65 40 55 30 45 ------ --- --- ---
Constancia silty clay -------------- 55 70 45 60 35 50
Consumo clay, 40 to 60 percent slopes,
eroded- ----- --- -------- -------- -----
Cortada silty clay loam ----------- 60 75 50 ___65 40 55 ----
Daguey clay, 12 to 20 percent slopes----------------_---_ --- 8 15 10 20
Ensenada gravelly clay, 2 to 12 per-
cent slopes ------------------- 30 40 25 35 20 25
Fraternidad clay, 2 to 5 percent slopes_ 55 70 45 60 35 50 -
Fraternidad clay, 5 to 12 percent
slopes, eroded ----- --40 50 30 40 25 30
Humatas clay, 20 to 40 percent slopes,
eroded ---------- ---- ---- ---------------------- 6 12 8 18
Humatas clay, 40 to 60 percent slopes,
eroded --- ----------------------------- -------------------- -------
Jacaguas silty clay loam--__________ 40 50 30 40 25 30---
Jacana clay, 5 to 12 percent slopes -- --
Juana Diaz clay loam, 12 to 20 per-
cent slopes -----------------__ -- ----- ------- -__
Lares clay, 5 to 12 percent slopes ------ ------ -- .--- ---- ----- 8 15 10 20
Lirios clay loam, 40 to 60 percent
slopes, eroded ---------------------- ----- ---- ------------ ------- 4 8
Llanos clay, 2 to 5 percent slopes --------------------------------------- ---- --- -
Llanos clay, 5 to 12 percent slopes,
eroded ---------------------------------------- --- ------ --------
Los Guineos clay, 20 to 40 percent
slopes ------------ ----- ---- ------ --- 5 10 8 18
Los Guineos clay, 40 to 60 percent
slopes --------------------------------_-- 4 8
Machuelo clay -------------------_ 50 65 40 55 30 45--------
Maraguez silty clay loam, 40 to 60
percent slopes, eroded----____ -- ----- -------- ------- -------------- 4 8
Maricao clay, 20 to 60 percent slopes,
eroded --------------------------------------- --------------- ---- -------- 4 8
Montegrande clay, 2 to 12 percent
slopes ----------40 50 30 40 25 30
Morado clay loam, 20 to 40 percent
slopes, eroded ------------------------- --------------- ---------------------- 5 10 7 15
Morado clay loam, 40 to 60 percent
slopes, eroded ------------------------------------- ------- ------- -------- ----_ 4 8
Mucara silty clay, 12 to 20 percent
slopes, eroded ------------------------------------- -------- -------------_----- 6 12 8 18
Mucara silty clay, 20 to 40 percent
slopes, eroded -------- ----- ------------------------ -------------------- 5 10 7 15
Mucara silty clay, 40 to 60 percent
slopes, eroded ------------------- ------- ------------------- -- 4 8 -------
Paso Seco clay, 2 to 5 percent slopes_ 55 70 45 60 35 50
Pellejas clay loam, 40 to 60 percent
slopes, eroded ------------- ----------------- -------------- -------------- --- 4 8
Quebrada silty clay loam, 12 to 20
percent slopes, eroded ------ ------- -------- -------- -------- -------- 6 12 8 18
Quebrada silty clay loam, 20 to 40
percent slopes, eroded --------- ---- -------------------- 5 10 7 15
Quebrada silty clay loam, 40 to 60
percent slopes, eroded --------------- --- -------- ---- ------------ 4 8
San Anton clay loam -------------- 60 75 50 65 40 55--- -
Toa silty clay loam ---------------- 60 75 50 65 40 55 -------------- 10 20
Yauco silty clay loam, 2 to 5 percent 4
slopes------------------------ 40 50 0 40 25 30










PONCE AREA OF SOUTHERN PUERTO RICO 51


principal crops under two levels of management
level management. Dashes indicate that the soil is not suited to the crop or the crop ordinarily is not grown on that soil. Only
are listed]



Plantains Bananas Taniers Pigeonpeas (Diosorea) Corn Tomatoes Peppers



A B A B A B A B A B A B A B A B

Thou. Thou- Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt Cwt
sands sands


15 25 20 35 60 120 ----_------____ 125 250 ------------- -- .---

--- .-...---------------. .--- -- -- -.- .-- -_-- -- _75 200 --- --- --- ----------- -..

------- 6 10 ------------- 6 12




.-------- .-------- .------. --- .------.------- ------- ------- -- 10 20 100 250 80 200
15 25 20 35 60 120 ----- ------- 125 -250--------

----- ------- ----- --------- ------- ------- ------- ------- ------- --------- ------- ------- ------- ------- -----
10 20 100 250 .

---- -- I. -. -- ---- ---I-.-- --.. -.- ----.-- --- ------- 10 20 100 250 8

15 25 20 35 60 120 -------_-_---- 125 250 -- --- ---. --- ----

-- -. -------------... . . ------___ __ -75 200- -- -
.-..-. --.- .- 6 12 75 200 80 200
.--..--- -------------... ---- -- -----. -6 10 ------ -----___ 8 14 75 200 80 200

..... ... ... .. .... ..--- --- ---- 6 10 ..- -2
15 25 20 35 60 120 ---- -_----- 125 250 5 10 .------ -__- 60 100


..---_--------------------------.- ------ _--8 I 16 100 250 80 200

.------------------------------------ ---6 10 ------------__ -- 8 16 100 250 80 200

.------- --------------- -------------- ---- -----100 200 1 5 00. 0







--- -------------------------------- 6 10 ______________ -------------------------------6 12




12 20 15 30 50 90 6 10 --- _______ 6 10 ------------- 40 100
---- ----------I----------------------------------- -----------------------------------




....... --- -....... -______.__.______.____ _____ ._ ________ _____.---------------- ------ ------20 8- 2- ~ -








12 20 15 30 50 90 6 10 -----_______--- 6 10 --.______ -- 40 100
--- ------------- -------------- -------- 100-0- .-----------------------------------
------ ---- ---------- ---------- ---------- ---- ------------ ------- ------- ------- ------- -------












--------------------- 10 20 100 250 00 200
S-------------------- -- 10 20 ---- ---- --200
---------- I---------------------------- ------- --------------------- -----------------------------------
--------..------- --....--------------- ----------------------------------- ------- ------- ------- ------- ------- ---




12 20 15 30 50 90 6 10 ------- ------ 1 6 10 100---- 250--- 40 100




15 2 20 3 8 1205 30.. ... .... ..------------------- 1 20 .------- 40 200


--------------- I -------- -- -------.-------.-------.------- ------- ------- ---i -----------------------------------








52 SOIL SURVEY

TABLE 4.-Estimated average yields per acre of principal pasture grasses under two levels of management
[Yields in the A columns are those expected under common management; yields in the B columns are those expected under high
level management. Dashes indicate that the soil is not suited to the crop or the crop ordinarily is not grown on that soil. Only
arable soils are listed]

Stargrass Pangolagrass Guineagrass Merkergrass
Soil
A B A B A B A B

AUM1 AUM1 AUM AUM1 AUM AUM' Tons Tons
Adjuntas clay, 40 to 60 percent slopes, eroded --------- 15 21 15 21 ---- -------- 30 45
Aguilita gravelly clay loam, 12 to 20 percent slopes .------------- ---- 2 4 -----
Aguilita gravelly clay loam, 20 to 60 percent slopes ----------- ---------2 4
Alonso clay, 20 to 40 percent slopes, eroded ----------- 15 21 15 21 -------- -------- 30 45
Alonso clay, 40 to 60 percent slopes, eroded ..------ 15 21 15 21 ---- --...- --- __
Caguabo gravelly clay loam, 20 to 60 percent slopes,
eroded ---- -------- -- --------- 8 12 8 12 ---- ----- -_--
Callabo silty clay loam, 12 to 20 percent slopes -------------- ------------ ____ -- 2 4 -
Callabo silty clay loam, 20 to 40 percent slopes ----------------------- 2 4 ----
Callabo silty clay loam, 40 to 60 percent slopes, eroded---------- 2 4 -----. ---__
Consumo clay, 40 to 60 percent slopes, eroded ---------- 15 21 15 21 --__- ---- _---- ----0- ----
Cortada silty clay loam ---- ---------------- ---- -- ---- ------- ----- 30 60
Cuyon loam, 0 to 5 percent slopes --------------------------- ----- -- 1 2 -
Daguey clay, 12 to 20 percent slopes ------------------ 15 21 15 21 ---- --- --. 25 50
Ensenada gravelly clay, 2 to 12 percent slopes ------------- ---- ----3 6 --- -----
Fraternidad clay, 2 to 5 percent slopes ---------------------- ---- --- ---- 7 14 30 60
Fraternidad clay, 5 to 12 percent slopes, eroded --------------- --------- 7 14 30 60
Guanabano clay, 40 to 60 percent slopes ------- -------------- 2 4 ---- -
Humatas clay, 20 to 40 percent slopes, eroded --------- 14 21 14 21 ------ ------ 25 50
Humatas clay, 40 to 60 percent slopes, eroded ------- 14 21 14 21------- ----- ------
Humatas complex, 20 to 60 percent slopes -------------- 6 12 6 12 ----- -- --- --------------
Jacaguas silty clay loam --------------------- ---------- 2 14 25 50
Jacana clay, 5 to 12 percent slopes ------------------------- 2 6 ---.-- -.--
Juana Diaz clay loam, 12 to 20 percent slopes ------------- ---- --- 2 5 ----- ----
Juana Diaz clay loam, 20 to 40 percent slopes --- -- ------- ------------ 2 4 ----------
Lares clay, 5 to 12 percent slopes ------------------- 18 24 18 24 ------------ 25 50
Lirios clay loam, 40 to 60 percent slopes, eroded -------- 14 21 14 21 ------------ ------ -----
Llanos clay, 2 to 5 percent slopes -------- --- --- ---- 2 6 ---
Llanos clay, 5 to 12 percent slopes, eroded ---------- -- -----2 6 -- --------
Los Guineos clay, 20 to 40 percent slopes -------------- 13 19 13 19 ----------- 25 50
Los Guineos clay, 40 to 60 percent slopes ----- 13 19 13 19 ------ --- ---
Maraguez silty clay loam, 40 to 60 percent slopes, eroded 7 12 7 12 ------- -----
Maricao clay, 20 to 60 percent slopes, eroded --------- 13 19 13 19 ----------- ---
Montegrande clay, 2 to 12 percent slopes ------------- 18 24 18 24 --------------_-- 30 60
Morado clay loam, 20 to 40 percent slopes, eroded -- 7 12 7 12 ----- ------25 50
Morado clay loam, 40 to 60 percent slopes, eroded ------ 7 12 7 12 ---------------- -------
Mucara silty clay, 12 to 20 percent slopes, eroded --- 18 24 18 24 ---------------- 25 50
Mucara silty clay, 20 to 40 percent slopes, eroded --- 12 18 12 18 ------------ -- 25 50
Mucara silty clay, 40 to 60 percent slopes, eroded ----- 7 12 7 12 -------- --------
Paso Seco clay, 2 to 5 percent slopes ------------------------------ --------- 2 14 30 60
Pellejas clay loam, 40 to 60 percent slopes, eroded ----- 7 10 7 10 ---- ---- ---------
Quebrada silty clay loam, 12 to 20 percent slopes,
eroded ----------------------------- 18 24 18 24 --------------- 25 50
Quebrada silty clay loam, 20 to 40 percent slopes,
eroded --------------------- ------------------ 12 18 12 18 ---------------- 25 50
Quebrada silty clay loam, 40 to 60 percent slopes,
eroded --------------------------------- ------ 7 12 7 12 --------- ------
Reilly gravelly loam --------------------- ------ 18 24 18 24 --------------- 25 50
San Anton clay loam ------------------------- --------- 30 60
Toa silty clay loam --------------------------------- 18 24 18 24 --------------- 30 60
Yauco silty clay loam, 2 to 5 percentslopes ---------------------------------------- 2 6
Yauco silty clay loam, 5 to 12 percent slopes-- ------ ----- -- 2 6 -------

SAUM is animal-unit-months, a term used to express the carrying capacity of pasture. It is the number of months during the year
that 1 acre will provide grazing for 1 animal unit (1 cow, 1 horse, 1 mule, 5 hogs, or 7 sheep) without damage to the pasture.







PONCE AREA OF SOUTHERN PUERTO RICO 53

4. If needed, seedbeds are adequately prepared, tection from the wind is necessary. An elevation of
including leveling and smoothing, more than 1,500 feet is necessary for eucalyptus.
5. Crop variety, seed quality, and plant population
are considered for a specific soil or location. Woodland suitability groups
6. Weeds, plant diseases, and insects are ade- The soils of this survey area have been placed in
quately controlled. woodland suitability groups to help woodland owners
7. Runoff and erosion are kept within tolerable in planning the use of the soils for wood crops. Each
limits. group is made up of soils that are suited to the same
8. The irrigation system, amount of water, and kinds of trees, that need about the same management
frequency of irrigation fit the crop and soil. if the vegetation is similar, and that have the same
9. Stands are reseeded and reestablished regu- potential productivity.
larly. Each woodland group is identified by a three-part
10. Grazing is deferred and rotated as needed. symbol, for example, 2ol, 2c2, and 3d2. The potential
11. The stocking rate is controlled, productivity of the soils in the group is indicated by the
12. Harvesting is timed for the highest, most first number in the symbol: 1 means very high;
economical yields. 2, high; 3, moderately high; 4, moderate; and 5, low.
These ratings are based on field estimates of the po-
Woodland management and productivity tential productivity in board feet per acre per year of
two kinds of trees, Honduras pine and Honduras
Forests completely covered Puerto Rico in the early mahogany.
1500's when it was colonized. By 1880, most of the The second part of the woodland group symbol is a
forests had been cleared. Because some areas were not small letter that indicates the major kind of soil limi-
suitable for permanent cultivation, they were aban- station. The letter o means that the soil has few limita-
doned and later were invaded by inferior volunteer tions that restrict its use as woodland. The letter x
trees. means that the use of the soil is restricted by stones or
In many places in the survey area, woodland is an rocks. The letter d means that the use of the soil is
excellent use of the soils. The trees help conserve soil restricted by the rooting depth, for example, soils that
and water, minimize flooding, reduce the amount of are shallow to hard rock. The letter c means that the
soil that is lost as sediment in the rivers, and impede use of the soil is restricted by the amount of clay in
runoff until a time of dry weather. To use the soil as the upper part of the soil. The letter r means that the
woodland some noncommercial forests should be con- use of the soil is restricted by the steepness of slopes.
verted to commercial forests, other noncommercial The last part of the symbol is a number that indi-
forests should be protected in their natural state, and cates a difference in management. For example, the
unforested areas should be planted to trees. soils in woodland group 2cl require management that
In table 5, the average yearly growth per acre of differs from that required by the soils in group 2c2.
trees that are important for wood crops is expressed In table 5 the soils that are suitable for commercial
in board feet. The trees are Honduras pine, Honduras production of wood crops are rated for various man-
mahogany, teak, kadam, and eucalyptus. Available agement hazards or limitations. Slight, moderate, and
data are not yet adequate to establish an accurate in- severe are used to indicate the degree of the limitation.
dication of potential productivity for each wood crop. Ratings of the erosion hazard indicate the risk of
.The rate of growth varies according to soil charac- loss of soil in well managed woodland. The risk is
teristics and location. For example, a soil that is fa- slight if the expected soil loss is small, moderate if
vorable for mahogany is deep, well drained, and some measures are needed to control erosion during
neutral to mildly acid. It is at an elevation of less than logging and road construction, and severe if intensive
1,500 feet and is protected from wind. Such a soil management or special equipment and methods are
could be expected to produce 500 board feet per acre needed to prevent excessive loss of soil.
per year; a shallow but otherwise favorable soil, 450 Ratings of equipment limitation reflect the charac-
board feet a year; and a shallow and slightly acid but teristics and conditions of the soil that restrict use of
otherwise favorable soil, 400 board feet a year. Estab- the equipment generally needed in woodland manage-
lishing priorities for species within woodland groups is ment or harvesting. A rating of slight indicates that
difficult because the annual growth rate and the mar- use of equipment is not limited to a particular kind of
ket value differ. The annual growth rate of teak and equipment or time of year; moderate indicates a short
mahogany, for example, is considerably less than that seasonal limitation or a need for some modification in
of pine and kadam, both of which grow well in Puerto management or equipment; severe indicates a seasonal
Rico. limitation, a need for special equipment or manage-
Some choices are clear in considering priority within ment, or a hazard in the use of equipment.
a group. For example, for mahogany, an elevation of Seedling mortality ratings indicate the degree that
less than 1,500 feet and protection from the wind are the soil affects expected mortality of planted tree
necessary, but depth is not critical. For teak, an eleva- seedlings. Plant competition is not considered in the
tion of less than 1,500 feet and a well drained soil are ratings. Seedlings from good planting stock that are
required. For pine, a well drained, acid, moist sandy or properly planted during a period of sufficient rainfall
light clay soil is required, but fertility is not critical, are rated. A rating of slight indicates that the expected
For kadam, a deep, moist soil is preferred, and pro- mortality of the planted seedlings is less than 25 per-







PONCE AREA OF SOUTHERN PUERTO RICO 53

4. If needed, seedbeds are adequately prepared, tection from the wind is necessary. An elevation of
including leveling and smoothing, more than 1,500 feet is necessary for eucalyptus.
5. Crop variety, seed quality, and plant population
are considered for a specific soil or location. Woodland suitability groups
6. Weeds, plant diseases, and insects are ade- The soils of this survey area have been placed in
quately controlled. woodland suitability groups to help woodland owners
7. Runoff and erosion are kept within tolerable in planning the use of the soils for wood crops. Each
limits. group is made up of soils that are suited to the same
8. The irrigation system, amount of water, and kinds of trees, that need about the same management
frequency of irrigation fit the crop and soil. if the vegetation is similar, and that have the same
9. Stands are reseeded and reestablished regu- potential productivity.
larly. Each woodland group is identified by a three-part
10. Grazing is deferred and rotated as needed. symbol, for example, 2ol, 2c2, and 3d2. The potential
11. The stocking rate is controlled, productivity of the soils in the group is indicated by the
12. Harvesting is timed for the highest, most first number in the symbol: 1 means very high;
economical yields. 2, high; 3, moderately high; 4, moderate; and 5, low.
These ratings are based on field estimates of the po-
Woodland management and productivity tential productivity in board feet per acre per year of
two kinds of trees, Honduras pine and Honduras
Forests completely covered Puerto Rico in the early mahogany.
1500's when it was colonized. By 1880, most of the The second part of the woodland group symbol is a
forests had been cleared. Because some areas were not small letter that indicates the major kind of soil limi-
suitable for permanent cultivation, they were aban- station. The letter o means that the soil has few limita-
doned and later were invaded by inferior volunteer tions that restrict its use as woodland. The letter x
trees. means that the use of the soil is restricted by stones or
In many places in the survey area, woodland is an rocks. The letter d means that the use of the soil is
excellent use of the soils. The trees help conserve soil restricted by the rooting depth, for example, soils that
and water, minimize flooding, reduce the amount of are shallow to hard rock. The letter c means that the
soil that is lost as sediment in the rivers, and impede use of the soil is restricted by the amount of clay in
runoff until a time of dry weather. To use the soil as the upper part of the soil. The letter r means that the
woodland some noncommercial forests should be con- use of the soil is restricted by the steepness of slopes.
verted to commercial forests, other noncommercial The last part of the symbol is a number that indi-
forests should be protected in their natural state, and cates a difference in management. For example, the
unforested areas should be planted to trees. soils in woodland group 2cl require management that
In table 5, the average yearly growth per acre of differs from that required by the soils in group 2c2.
trees that are important for wood crops is expressed In table 5 the soils that are suitable for commercial
in board feet. The trees are Honduras pine, Honduras production of wood crops are rated for various man-
mahogany, teak, kadam, and eucalyptus. Available agement hazards or limitations. Slight, moderate, and
data are not yet adequate to establish an accurate in- severe are used to indicate the degree of the limitation.
dication of potential productivity for each wood crop. Ratings of the erosion hazard indicate the risk of
.The rate of growth varies according to soil charac- loss of soil in well managed woodland. The risk is
teristics and location. For example, a soil that is fa- slight if the expected soil loss is small, moderate if
vorable for mahogany is deep, well drained, and some measures are needed to control erosion during
neutral to mildly acid. It is at an elevation of less than logging and road construction, and severe if intensive
1,500 feet and is protected from wind. Such a soil management or special equipment and methods are
could be expected to produce 500 board feet per acre needed to prevent excessive loss of soil.
per year; a shallow but otherwise favorable soil, 450 Ratings of equipment limitation reflect the charac-
board feet a year; and a shallow and slightly acid but teristics and conditions of the soil that restrict use of
otherwise favorable soil, 400 board feet a year. Estab- the equipment generally needed in woodland manage-
lishing priorities for species within woodland groups is ment or harvesting. A rating of slight indicates that
difficult because the annual growth rate and the mar- use of equipment is not limited to a particular kind of
ket value differ. The annual growth rate of teak and equipment or time of year; moderate indicates a short
mahogany, for example, is considerably less than that seasonal limitation or a need for some modification in
of pine and kadam, both of which grow well in Puerto management or equipment; severe indicates a seasonal
Rico. limitation, a need for special equipment or manage-
Some choices are clear in considering priority within ment, or a hazard in the use of equipment.
a group. For example, for mahogany, an elevation of Seedling mortality ratings indicate the degree that
less than 1,500 feet and protection from the wind are the soil affects expected mortality of planted tree
necessary, but depth is not critical. For teak, an eleva- seedlings. Plant competition is not considered in the
tion of less than 1,500 feet and a well drained soil are ratings. Seedlings from good planting stock that are
required. For pine, a well drained, acid, moist sandy or properly planted during a period of sufficient rainfall
light clay soil is required, but fertility is not critical, are rated. A rating of slight indicates that the expected
For kadam, a deep, moist soil is preferred, and pro- mortality of the planted seedlings is less than 25 per-








54 SOIL SURVEY

TABLE 5.-Woodland management and productivity
[Only soils suitable for production of commercial trees are listed]

Potential productivity Limitations
Wood-
Soil land
group Important trees nnu Erosion Equipment Seedling
Important trees growth hazard limitation mortality
per acre

Board
feet
Adjuntas clay, 40 to 60 percent slopes, 3rl Honduras pine --------- 900 Severe ----- Severe --- Slight.
eroded. Teak --------- 250
Honduras mahogany _- 300
Aguilita gravelly clay loam, 12 to 20 2x1 Honduras mahogany 400 Slight ------ Slight -- ---Moderate.
percent slopes. Teak ---------------- 500
Aguilita gravelly clay loam, 20 to 60 3x1 Honduras mahogany --_ 300 Severe ----- Severe ----- Moderate.
percent slopes. Teak --------------- 00
Aguilita stony clay loam, 20 to 60 per- 3x1 Honduras mahogany -- 300 Severe ----- Severe ----- Moderate.
cent slopes. Teak ---------------_ 500
Alonso clay, 20 to 40 percent slopes, 2cl Honduras pine --- 1,350 Moderate --- Moderate -- Slight.
eroded. Eucalyptus ----------- 2,000
Kadam ------------ 1,800
Alonso clay, 40 to 60 percent slopes, 3c1 Honduras pine -------_ 1,100 Severe ----- Severe ----- Slight.
eroded. Eucalyptus ---_______ 2,000
Kadam --------------- 1,800
Caguabo gravelly clay loam, 20 to 60 4dl Honduras pine ----- 700 Severe ----- Severe ----- Moderate.
percent slopes, eroded.
Callabo silty clay loam, 12 to 20 per- 3dl Honduras mahogany ___ 250 Moderate -__ Moderate __ Moderate.
cent slopes.
Callabo silty clay loam, 20 to 40 percent 3d1 Honduras mahogany --_ 250 Moderate _- Moderate --- Moderate.
slopes.
Callabo silty clay loam, 40 to 60 percent 4d2 Honduras mahogany _- 200 Severe ----- Severe ----- Moderate.
slopes, eroded.
Consumo clay, 40 to 60 percent slopes, 3cl Honduras pine --------- 1,100 Severe ----- Severe ----- Slight.
eroded. Teak -------------- 250
Daguey clay, 12 to 20 percent slopes -- 2c2 Honduras pine --------- 1,300 Slight ----- Moderate --- Slight.
Teak 500
Humatas clay, 20 to 40 percent slopes, 2c1 Honduras pine _________ 1,100 Moderate _- Moderate --- Slight.
eroded. Teak ------- 400
Humatas clay, 40 to 60 percent slopes, 3cl Honduras pine -_______- 900 Severe ----- Severe ----- Slight.
eroded.
Humatas complex, 20 to 60 percent 3dc Honduras pine -------- 900 Severe ----- Severe --.-- Slight.
slopes.
Jacana clay, 5 to 12 percent slopes --- 2d1 Honduras mahogany _- 400 Slight ---_- Slight _----- Slight.

Juana Diaz clay loam, 12 to 20 percent 3d1 Honduras mahogany ___ 300 Moderate -- Moderate -- Moderate.
slopes.
Juana Diaz clay loam, 20 to 40 percent 3d1 Honduras mahogany _- 300 Moderate _- Moderate --- Moderate.
slopes.
Lares clay, 5 to 12 percent slopes .--- 2c2 Honduras pine ----- 1,300 Slight ------Moderate --_ Slight.
Teak ---------___- 500
Lirios clay loam, 40 to 60 percent slopes, 3cl Honduras pine ------ 900 Severe ----- Severe ----- Slight.
eroded. Teak----------------- 250









PONCE AREA OF SOUTHERN PUERTO RICO 55

TABLE 5.-Woodland management and productivity-Continued

Potential productivity Limitations
Wood-
Soil land Annual
group Imptant t s nnua Erosion Equipment Seedling
Important trees growth hazard limitation mortality
per acre

Board
feet

Los Guineos clay, 20 to 40 percent 2c1 Honduras pine -------- 1,400 Moderate --- Moderate _- Slight.
slopes. Eucalyptus --------- 2,000
Kadam -------------- 1,800

Los Guineos clay, 40 to 60 percent 2c3 Honduras pine ------ 1,300 Moderate --- Severe ----- Slight.
slopes. Eucalyptus ----------- 2,000
Kadam -- ----------- 1,800

Los Guineos-Maricao association, steep -- 2c3 Honduras pine _---_---_ 1,300 Severe ----- Severe ----- Slight.
Eucalyptus ---------- 2,000
Kadam --------- 1,800

Los Guineos-Maricao-Stony rock land 3x2 Honduras pine -------- 1,100 Moderate __ Severe ----- Slight.
association, steep. Eucalyptus ---- 1,800
Kadam -------------- 1,600

Maraguez silty clay loam, 40 to 60 per- 3rl Honduras pine --- --- 800 Severe ----- Severe ----- Slight.
cent slopes, eroded. Mahogany --------- 400
Kadam ------ 1,400

Maricao clay, 20 to 60 percent slopes, 2c3 Honduras pine ---- 1,300 Severe ----- Severe ----- Slight.
eroded. Eucalyptus ------ 2,000
Morado clay loam, 20 to 40 percent 3d2 Honduras pine ------ 800 Moderate --- Moderate ___ Slight.
slopes, eroded. Mahogany ---- 400
Kadam ------1,400

Morado clay loam, 40 to 60 percent 3d3 Honduras pine -------- 800 Severe ----- Severe ----- Slight.
slopes, eroded. Mahogany ------ 400
Kadam --------- 1,400

Mucara silty clay, 12 to 20 percent 3d2 Honduras pine ------- 900 Moderate -_ Moderate _- Slight.
slopes, eroded. Mahogany ------------ 400
Kadam ------------ 1,400

Mucara silty clay, 20 to 40 percent 3d2 Honduras pine -------- 900 Moderate _- Moderate -- Slight.
slopes, eroded. Mahogany --------- 400
Kadam ---------- 1,400

Mucara silty clay, 40 to 60 percent 3d3 Honduras pine --------- 900 Severe ----- Severe ----- Slight.
slopes, eroded. Mahogany ----- ---- 400
Kadam --------- 1,400

Pellejas clay loam, 40 to 60 percent 3rl Honduras pine ------ 1,000 Severe ----- Severe ----- Slight.
slopes, eroded. Teak ------- 250
Mahogany--------- 300

Quebrada silty clay loam, 12 to 20 per- 2c4 Honduras pine 1,100 Moderate -- Moderate Slight.
cent slopes, eroded. Mahogany _------- 450
Quebrada silty clay loam, 20 to 40 per- 2c4 Honduras pine ------- 1,100 Moderate --- Moderate _- Slight.
cent slopes, eroded. Mahogany--------- 450
Quebrada silty clay loam, 40 to 60 per- 3rl Honduras pine __------- 1,000 Severe ---- Severe ----- Slight.
cent slopes, eroded. Mahogany -- ------ 275
Yauco silty clay loam, 2 to 5 percent 2o1 Honduras mahogany _- 500 Slight ------ Slight ----- Slight.
slopes.
Yauco silty clay loam, 5 to 12 percent 2ol Honduras mahogany 500 Slight ----- Slight ----- Slight.
slopes.








56 SOIL SURVEY

cent; moderate, 25 to 50 percent; and severe, more The best soils for this use are those that are not wet,
than 50 percent, are firm after rains, are not dusty when dry, and are
not subject to flooding more than once during the
period of use. They should have moderate slopes and
Recreation have few or no stones or boulders on the surface.
The soils of the survey area are rated in table 6 Engineering uses of the soils
according to limitations that affect their suitability
for camp areas, picnic areas, playgrounds, and paths This section is useful to planning commissions, town
and trails. The ratings are based on such restrictive and city managers, land developers, engineers, contrac-
soil features as flooding, wetness, slope, and texture of tors, farmers, and others who need information about
the surface layer. Not considered in these ratings, but soils that are used as structural material or as a foun-
important in evaluating a site, are location and acces- dation on which structures are built.
sibility of the area, size and shape of the area and its Among the properties of soils highly important in
scenic quality, the ability of the soil to support vegeta- engineering are permeability, strength, compaction
tion, access to water, potential water impoundment characteristics, soil drainage condition, shrink-swell
sites available, and either access to public sewerlines potential, grain size, plasticity, and soil reaction. Also
or capacity of the soil to absorb septic tank effluent. important are depth to the water table, depth to bed-
Soils subject to flooding are limited, in varying degree, rock, and soil slope. These properties, in various de-
for recreation use by the duration of flooding and the grees and combinations, affect construction and
season when flooding occurs. Onsite assessment of maintenance of roads, airports, pipelines, foundations
height, duration, and frequency of flooding is essential for small buildings, irrigation systems, ponds and small
in planning recreation facilities, dams, and systems for disposal of sewage and refuse.
In table 6 the limitations of soils are rated as mod- Information in this section of the soil survey can be
erate or severe. Moderate indicates that the limitations helpful to those who-
can be overcome or alleviated by planning, design, or 1. Select potential residential, industrial, commer-
special maintenance. Severe indicates that the soil cial, and recreational areas.
properties are not favorable and that limitations can 2. Evaluate alternate routes for roads, highways,
be offset only by costly soil reclamation, special design, pipelines, and underground cables.
intensive maintenance, limited use, or by a combina- 3. Seek sources of gravel, sand, or clay.
tion of these measures. 4. Plan farm drainage systems, irrigation systems,
The information in table 6 can be supplemented by ponds, terraces, and other structures for con-
additional information in other parts of this survey, trolling water and conserving soil.
Especially helpful are interpretations for septic tank 5. Correlate performance of structures already
absorption fields, dwellings without basements, and built with properties of the soils on which they
local roads and streets, which are given in table 8. are built, for the purpose of predicting perfor-
Camp areas require such site preparation as shaping mance of structures on the same or similar kinds
and leveling tent and parking areas, stabilizing roads of soil in other locations.
and intensively used areas, and installing sanitary 6. Predict the, trafficability of soils for cross-
facilities and utility lines. Camp areas are subject to country movement of vehicles and construction
heavy foot traffic and some vehicular traffic. The best equipment.
soils for this use have mild slopes and are not wet nor 7. Develop preliminary estimates pertinent to con-
subject to flooding during the period of use. The sur- struction in a particular area.
face has few or no stones or boulders, absorbs rainfall
readily but remains firm, and is not dusty when dry. Most of the information in this section is presented
Strong slopes and stones or boulders can greatly in- in tables. Table 7 shows estimated soil properties sig-
crease the cost of constructing camping sites, nificant in engineering. Table 8 gives interpretations
Picnic areas are subject to heavy foot traffic. Most for various engineering uses. Table 9 shows the results
vehicular traffic is confined to access roads and parking of engineering laboratory tests on soil samples.
areas. The best soils for use as picnic areas are firm This information, along with the soil map and data
when wet, are not dusty when dry, are not subject to in other parts of this publication, can be used to make
flooding during the period of use, and do not have interpretations, in addition to those given in tables 7
slopes or stones or boulders that will increase the cost and 8, and to make useful maps.
of shaping sites or of building access roads and parking This information, however, does not eliminate the
areas. need for further investigation at sites selected for en-
Playgrounds require soils that can withstand inten- gineering works, especially works that involve heavy
sive foot traffic. The best soils are almost level and are loads or that require excavations to depths greater than
not wet nor subject to flooding during the season of those shown in the tables, generally depths of more
use. The surface is free of stones or boulders, is firm than 6 feet. Also, inspection of sites, especially the
after rains, and is not dusty when dry. If shaping is small ones, is needed because many delineated areas
required to obtain a uniform grade, the depth of the of a given soil can include small areas of other soils
soil over rock should be sufficient to allow necessary that have strongly contrasting properties and different
grading. suitability or limitations for soil engineering.
Paths and trails for walking, horseback riding, and 2 PEDRO CATONI, engineer, Soil Conservation Service, helped
bicycling should require little or no cutting and filling, to prepare this section.








56 SOIL SURVEY

cent; moderate, 25 to 50 percent; and severe, more The best soils for this use are those that are not wet,
than 50 percent, are firm after rains, are not dusty when dry, and are
not subject to flooding more than once during the
period of use. They should have moderate slopes and
Recreation have few or no stones or boulders on the surface.
The soils of the survey area are rated in table 6 Engineering uses of the soils
according to limitations that affect their suitability
for camp areas, picnic areas, playgrounds, and paths This section is useful to planning commissions, town
and trails. The ratings are based on such restrictive and city managers, land developers, engineers, contrac-
soil features as flooding, wetness, slope, and texture of tors, farmers, and others who need information about
the surface layer. Not considered in these ratings, but soils that are used as structural material or as a foun-
important in evaluating a site, are location and acces- dation on which structures are built.
sibility of the area, size and shape of the area and its Among the properties of soils highly important in
scenic quality, the ability of the soil to support vegeta- engineering are permeability, strength, compaction
tion, access to water, potential water impoundment characteristics, soil drainage condition, shrink-swell
sites available, and either access to public sewerlines potential, grain size, plasticity, and soil reaction. Also
or capacity of the soil to absorb septic tank effluent. important are depth to the water table, depth to bed-
Soils subject to flooding are limited, in varying degree, rock, and soil slope. These properties, in various de-
for recreation use by the duration of flooding and the grees and combinations, affect construction and
season when flooding occurs. Onsite assessment of maintenance of roads, airports, pipelines, foundations
height, duration, and frequency of flooding is essential for small buildings, irrigation systems, ponds and small
in planning recreation facilities, dams, and systems for disposal of sewage and refuse.
In table 6 the limitations of soils are rated as mod- Information in this section of the soil survey can be
erate or severe. Moderate indicates that the limitations helpful to those who-
can be overcome or alleviated by planning, design, or 1. Select potential residential, industrial, commer-
special maintenance. Severe indicates that the soil cial, and recreational areas.
properties are not favorable and that limitations can 2. Evaluate alternate routes for roads, highways,
be offset only by costly soil reclamation, special design, pipelines, and underground cables.
intensive maintenance, limited use, or by a combina- 3. Seek sources of gravel, sand, or clay.
tion of these measures. 4. Plan farm drainage systems, irrigation systems,
The information in table 6 can be supplemented by ponds, terraces, and other structures for con-
additional information in other parts of this survey, trolling water and conserving soil.
Especially helpful are interpretations for septic tank 5. Correlate performance of structures already
absorption fields, dwellings without basements, and built with properties of the soils on which they
local roads and streets, which are given in table 8. are built, for the purpose of predicting perfor-
Camp areas require such site preparation as shaping mance of structures on the same or similar kinds
and leveling tent and parking areas, stabilizing roads of soil in other locations.
and intensively used areas, and installing sanitary 6. Predict the, trafficability of soils for cross-
facilities and utility lines. Camp areas are subject to country movement of vehicles and construction
heavy foot traffic and some vehicular traffic. The best equipment.
soils for this use have mild slopes and are not wet nor 7. Develop preliminary estimates pertinent to con-
subject to flooding during the period of use. The sur- struction in a particular area.
face has few or no stones or boulders, absorbs rainfall
readily but remains firm, and is not dusty when dry. Most of the information in this section is presented
Strong slopes and stones or boulders can greatly in- in tables. Table 7 shows estimated soil properties sig-
crease the cost of constructing camping sites, nificant in engineering. Table 8 gives interpretations
Picnic areas are subject to heavy foot traffic. Most for various engineering uses. Table 9 shows the results
vehicular traffic is confined to access roads and parking of engineering laboratory tests on soil samples.
areas. The best soils for use as picnic areas are firm This information, along with the soil map and data
when wet, are not dusty when dry, are not subject to in other parts of this publication, can be used to make
flooding during the period of use, and do not have interpretations, in addition to those given in tables 7
slopes or stones or boulders that will increase the cost and 8, and to make useful maps.
of shaping sites or of building access roads and parking This information, however, does not eliminate the
areas. need for further investigation at sites selected for en-
Playgrounds require soils that can withstand inten- gineering works, especially works that involve heavy
sive foot traffic. The best soils are almost level and are loads or that require excavations to depths greater than
not wet nor subject to flooding during the season of those shown in the tables, generally depths of more
use. The surface is free of stones or boulders, is firm than 6 feet. Also, inspection of sites, especially the
after rains, and is not dusty when dry. If shaping is small ones, is needed because many delineated areas
required to obtain a uniform grade, the depth of the of a given soil can include small areas of other soils
soil over rock should be sufficient to allow necessary that have strongly contrasting properties and different
grading. suitability or limitations for soil engineering.
Paths and trails for walking, horseback riding, and 2 PEDRO CATONI, engineer, Soil Conservation Service, helped
bicycling should require little or no cutting and filling, to prepare this section.









PONCE AREA OF SOUTHERN PUERTO RICO 57

TABLE 6.-Recreation

Degree and kind of limitation for-
Soil and map symbols
Camp areas Picnic areas Playgrounds Paths and trails

Adjuntas: AaF2 ------- Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
soil texture, soil texture, soil texture, soil texture.

Aguilita: AgD, AgF, AhF- Severe: slope, coarse Severe: slope, coarse Severe: slope--------- Severe: slope, coarse
fragments, fragments. fragments on
surface.

Alonso: AnE2, AnF2 ---- Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
soil texture, soil texture, soil texture, soil texture.

Caguabo: CbF2, CdF --- Severe: slope--------- Severe: slope------- Severe: slope--------- Severe: slope.
Callabo: CoD, CoE, CoF2_ Severe: slope--------- Severe: slope ------- Severe: slope --------- Moderate if slope is 12
to 25 percent; severe
if slope is more than
25 percent.

Cintrona: Cr ---------- Severe: flooding, sur- Severe: flooding, Severe: flooding, Severe: poorly
face soil texture, surface soil texture, surface soil texture, drained, surface soil
poorly drained, poorly drained, poorly drained, texture.

Constancia: Ct -------- Severe surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, somewhat texture, somewhat texture, somewhat texture.
poorly drained, poorly drained, poorly drained,
flooding, flooding, flooding.

Consume: CuF2 ------- Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
soil texture, soil texture, soil texture, soil texture.
Cortada: Cx ---------- Moderate: surface Moderate: surface Moderate: surface Moderate: surface
soil texture, flooding, soil texture, flooding, soil texture, flooding, soil texture.

Cuyon: CyB ------- Severe: flooding -- --- Severe: flooding ______ Severe: flooding ----- Moderate: flooding.
Daguey: DaD --------- Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, slope, texture, slope, texture, slope, texture, slope.

Ensenada: EnC -------- Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, coarse texture, coarse texture, coarse texture, coarse frag-
fragments, fragments. fragments, ments on surface.
Fe: Fe---------------- Severe: permeability, Severe: surface soil Severe: surface soil Severe: surface soil
surface soil texture, texture, texture, texture.
Fraternidad: FtB, FtC2-- Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture, texture, permeability, texture.

Guanabano: GoF ----- Severe: slope, coarse Severe: slope, coarse Severe: slope, coarse Severe: slope, coarse
fragments. fragments. fragments, fragments on
surface.

Humatas: HmE2, HmF2, Severe: slope, surface Severe: slope, surface Severe: slope, sur- Severe: slope, surface
HxF. soil texture, soil texture, face soil texture. soil texture.
Hydraquents: Hy.
Soil material too vari-
able for interpreta-
tions.
Hydraquents, saline: Hz_ Severe: very poorly Severe: very poorly Severe: very poorly Severe: very poorly
drained, drained, drained, drained.

Jacaguas: Jg ---_--- Moderate: flooding Moderate: flooding, Moderate: flooding, Moderate: surface
surface soil texture, surface soil texture, surface soil texture, soil texture.

Jacana: JnC -------- Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture, texture, permeability, texture.

Juana Diaz: JzD, JzE -_ Severe: slope------- Severe: slope---- -- Severe: slope --------- Moderate if slope is 12
to 25 percent; severe
if slope is more than
25 percent.








58 SOIL SURVEY

TABLE 6.-Recreation-Continued

Degree and kind of limitation for-
Soil and map symbols
Camp areas Picnic areas Playgrounds Paths and trails

Lares: LeC ------------Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture, texture, texture.
Lirios: LmF2 -------- Severe: slope --- ---- Severe: slope------ Severe: slope -------- Severe: slope.
Llanos: LnB, LnC2 ------ Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture, texture, texture.
Los Guineos: LuE, LuF, Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
LyFX, LzFX. soil texture, soil texture, soil texture, soil texture.
Machuelo: Ma --------- Severe: poorly Severe: poorly Severe: poorly Severe: poorly
drained, surface soil drained, surface soil drained, surface soil drained, surface soil
texture, flooding, texture, flooding, texture, flooding, texture.
Maraguez: MeF2------- Severe: slope-------- Severe: slope ----- Severe: slope ------- Severe: slope.
Maricao: MkF2 ---Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
soil texture. soil texture. soil texture. soil texture.
Meros: Mr --------- Moderate: surface Moderate: surface Severe: surface soil Severe: surface soil
soil texture. soil texture, texture, texture.
Montegrande: MsC Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture. texture, texture, texture.
Morado: MtE2, MtF2 --- Severe: slope--------- Severe: slope- -- Severe: slope---_- Moderate if slope is 12
to 25 percent; severe
if slope is more than
25 percent.
Mucara: MuD2, MuE2, Severe: slope, surface Severe: slope, surface Severe: slope, surface Severe: slope, surface
MuF2. soil texture, soil texture. soil texture, soil texture.
Paso Seco: PaB -------- Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture. texture, permeability, texture.
Pellejas: PeF2-------- Severe: slope------- Severe: slope------ Severe: slope ------ Severe: slope.
Quebrada: QeD2, QeE2, Severe: slope--------- Severe: slope---- Severe: slope ----- Moderate if slope is 12
QeF2. to 25 percent; severe
if slope is more than
25 percent.
Reilly: Re ------------- Severe: flooding ------ Severe: flooding ------ Severe: flooding ----- Moderate: flooding.
Riverwash: Rw ------- Severe: flooding, Severe: flooding, Severe: flooding, Severe: flooding,
coarse fragments, coarse fragments, coarse fragments on coarse fragments on
stones, stones, surface, stones, surface, stones.
San Anton: Sa -------- Moderate: flooding, Moderate: flooding Moderate: flooding, Moderate: flooding,
surface soil texture, surface soil texture, surface soil texture. surface soil texture.
Serrano: Se ----------- Severe: poorly Severe: poorly Severe: poorly Severe: poorly
drained, drained, drained, drained.
Teresa: Te ------------ Severe: surface soil Severe: surface soil Severe: surface soil Severe: surface soil
texture, texture, texture. texture.
Tidal flats: Tf--------
Soil material too vari-
able for interpreta-
tions.
Toa: To--------------- Moderate: flooding, Moderate: flooding, Moderate: flooding, Moderate: flooding,
surface soil texture. surface soil texture. surface soil texture, surface soil texture.
Tuque: TuF ----- Severe: slope, coarse Severe: slope, coarse Severe: slope, coarse Severe: coarse frag-
fragments. fragments, fragments, ments on surface.







PONCE AREA OF SOUTHERN PUERTO RICO 59

TABLE 6.-Recreation-Continued

Degree and kind of limitation for-
Soil and map symbols
Camp areas Picnic areas Playgrounds Paths and trails

Yauco: YcB, YcC ------- Moderate: surface Moderate: surface Moderate if slope is 2 to Moderate: surface
soil texture, soil texture. 6 percent; severe if soil texture.
slope is more than 6
percent: surface soil
texture.


Some of the terms used in this soil survey have a through A-7 on the basis of grain-size distribution,
special meaning in soil science. The Glossary defines liquid limit, and plasticity index. In group A-1 are
many of these terms. gravelly soils of high bearing strength, or the best
S soils for subgrade (foundation). At the other extreme,
Soil properties significant in engineering in group A-7, are clay soils that have low strength
Several estimated soil properties significant in en- when wet and that are the poorest soils for subgrade.
gineering are given in table 7. These estimates are Where laboratory data are available to justify a
made for typical soil profiles, by layers sufficiently dif- further breakdown, the A-i, A-2, and A-7 groups are
ferent to have different significance for soil engineer- divided as follows: A-i-a, A-l-b, A-2-4, A-2-5,
ing. The estimates are based on field observations made A-2-6, A-2-7, A-7-5, and A-7-6. As an additional
in the course of mapping, on test data for these and refinement, the engineering value of a soil material can
similar soils, and on experience with the same kinds of be indicated by a group index number. Group indexes
soil in other survey areas. Following are explanations range from 0 for the best material to 20 or more for
of some of the column headings in table 7. the poorest. The AASHTO classification for tested
Depth to bedrock is distance from the surface of the soils, with group index numbers in parentheses, is
soil to the rock layer, shown in table 9; the estimated classification, without
Depth to seasonal high water table is distance from group index numbers, is given in table 7 for all soils
the surface of the drained soil to the highest level that mapped in the survey area.
ground water reaches in the soil in most years. Liquid limit and plasticity index indicate the effect
Soil texture is described in table 7 in the standard of water on the strength and consistence of soil ma-
terms used by the Department of Agriculture. These trial. As the moisture content of a clayey soil is in-
terms take into account relative percentages of sand, creased from a dry state, the material changes from
silt, and clay in soil material that is less than 2 milli- semisolid to plastic. If the moisture content is further
meters in diameter. "Loam," for example, is soil ma- increased, the material changes from plastic to liquid.
trial that is 7 to 27 percent clay, 28 to 50 percent silt, The plastic limit is the moisture content at which the
and less than 52 percent sand. If the soil contains soil material changes from semisolid to plastic; and
gravel or other particles coarser than sand, an appro- the liquid limit, from plastic to liquid. The plasticity
private modifier is added, for example, "gravelly loamy index is the numerical difference between the liquid
sand." "Sand," "silt," "clay," and some of the other limit and the plastic limit. It indicates the range of
terms used are defined in the Glossary of this soil sur- moisture content within which a soil material is plas-
vey. tic. The data on liquid limit and plasticity index in
The two systems most commonly used in classifying table 7 are estimates, but in table 9 they are based on
samples of soils for engineering are the Unified system tests of soil samples.
(2) used by SCS engineers, the Department of De- Permeability is that quality of a soil that enables it
fense, and others and the system adopted by the Amer- to transmit water or air. It is estimated on the basis
ican Association of State Highway and Transportation of those soil characteristics observed in the field, par-
Officials (AASHTO) (1). ticularly structure and texture. The estimates in table
In the Unified system, soils are classified according 7 do not take into account lateral seepage or such tran-
to particle-size distribution, plasticity, liquid limit, and sient soil features as plowpans and surface crusts.
organic matter content. Soils are grouped in 15 classes. Available water capacity is the ability of soils to
There are eight classes of coarse-grained soils, identi- hold water for use by most plants. It is commonly de-
fied as GW, GP, GM, GC, SW, SP, SM, and SC; six fined as the difference between the amount of water in
classes of fine-grained soils, identified as ML, CL, OL, the soil at field capacity and the amount at the wilting
MH, CH, and OH; and one class of highly organic point of most crop plants.
soils, identified as Pt. Soils on the borderline between Reaction is the degree of acidity or alkalinity of a
two classes are designated by symbols for both classes, soil, expressed in pH values. The pH value and terms
for example, CL-ML. used to describe soil reaction are explained in the
The AASHTO system is used to classify soils ac- Glossary.
cording to those properties that affect use in highway Shrink-swell potential is the relative change in vol-
construction and maintenance. In this system, a soil is ume of soil material to be expected with changes in
placed in one of seven basic groups ranging from A-1 moisture content, that is, the extent to which the soil








60 SOIL SURVEY

TABLE 7.-Estimated soil properties
[The symbol > means more than; < means less than.

Depth to- Classification
Coarse
Soil series Depth fraction
and Seasonal from USDA texture greater
map symbols Bedrock high surface Unified AASHTO than
water 3 inches
table

Feet Feet Inches Percent

Adjuntas: AaF2 -------- 4-6 >5 0-24 Clay ---------------------- MH A-7
24-48 Strongly and partly weathered
volcanic rock.
Aguilita: AgD, AgF, AhF >5 >5 0-13 Gravelly clay loam ----------- GC, ML, CL A-2, A-6 5-80
A-7
13-60 Gravelly limestone that is more
than 50 percent hard lime-
stone fragments.
Alonso: AnE2, AnF2 ---- >5 >5 0-60 Clay ----------------------- MH A-7 -
Caguabo: CbF2, CdF ---- 1-1.5 >5 0-12 Gravelly clay loam ----------- GM A-2 0-20
12-17 Highly weathered and partly
weathered volcanic rock.
17 Hard, semiconsolidated volcanic
rock.
Callabo: CoD, CoE, CoF2 2-3 >5 0-13 Silty clay loam --------------- MH A-7 0-10
13-19 Clay loam ----------------- ML, CL A-7 0-10
19-27 Highly weathered volcanic
rock.
27 Semiconsolidated volcanic rock.
Cintrona: Cr ---------- >5 3-5 0-60 Clay ---------------------- CH A-7 -
Constancia: Ct --------- >5 3-5 0-65 Silty clay, clay --------------- MH, CH A-7 -
Consumo: CuF2 --------- >5 >5 0-60 Clay, silty clay ------------ MH A-7 -
Cortada: Cx --------- >5 >5 0-28 Silty clay loam ------------- CL, ML A-7 _
28-68 Silt loam -------------- ML A-4 ----
Cuyon: CyB ------------ >5 >5 0-11 Loam ------------------- ML A-4 -
11-60 Sand and gravel ---- --- GP, GM A-1 0-50
Daguey: DaD ----------- >5 >5 0-60 Clay ------------------- MH A-7 -

Ensenada: EnC -------- >5 >5 0-60 Gravelly clay --------------- GC A-2 0-30
Fe: Fe ----------------- >5 >5 0-60 Clay ----- ------------ CH A-7 0-5
Fraternidad: FtB, F+C2 -- >5 >5 0-60 Clay -------------------- CH A-7 ----
Guanabano: GoF -------- 4-6 >5 0-11 Clay--- -- ------------ MH, CH A-7 10-20
11-50 Silty clay loam------- MH, CL A-7 0-10
50-60 Gravelly silty clay loam ------- GM, ML A-4 0-25
Humatas: HmE2, HmF2,
HxF ------------------- >5 >5 0-60 Clay ---------------------- MH A-7 -----------
Hydraquents: Hy.
Properties too variable
to be estimated.
Hydraquents, saline: Hz.
Properties too variable
to be estimated.
Jacaguas: Jg ----------- >5 >5 0-14 Silty clay loam ---------------CL A-6 5-10
14-60 Very cobbly clay loam -------- GC, SC, CL A-4, A-2 30-70
Jacana: JnC------------ 2-3 >5 0-27 Clay ----------- MH, CH A-7 -- --
27 Weathered volcanic rock.

See footnote at ind of table.








PONCE AREA OF SOUTHERN PUERTO RICO 61

significant in engineering
Corrosivity estimates apply to the entire soil profile]

Percentage passing sieve- Corrosivity to-

Liquid Plasticity Perme- Available Shrink-
No. 4 No. 10 No. 40 No. 200 limit index ability water Reaction swell
(4.7 (2.0 (0.42 (0.074 capacity potential Uncoated Concrete
mm) mm) mm) mm) steel

Inches per Inches per pH
hour inch of soil

95-100 95-100 85-95 70-90 55-60 15-20 0.6-2.0 0.11-0.14 4.5-5.5 Moderate High ----- High.


40-80 30-80 25-75 25-50 25-50 10-20 0.6-2.0 0.08-0.10 7.9-8.4 Moderate- Low ------ Low.





100 100 85-100 85-95 60-70 15-25 0.6-2.0 0.12-0.15 4.5-5.5 Moderate- Moderate-- High.
30-50 25-45 20-40 15-35 55-65 17-22 0.6-2.0 0.06-0.10 6.1-6.5 Moderate- Low ----- Low.




90-100 90-100 85-95 80-90 55-60 20-25 0.6-2.0 0.12-0.16 6.1-7.3 Moderate Low ------ Low.
85-100 85-100 75-90 55-70 40-45 10-15 0.6-2.0 0.12-0.16 6.1-7.3 Moderate- Low ------ Low.



100 100 90-100 80-95 75-80 45-50 0.06-0.2 0.14-0.16 6.6-8.4 High ----- High ---- Low.
100 95-100 85-95 70-90 75-85 40-50 0.06-0.2 0.10-0.14 7.9-8.4 High --_ High ----- Low.
100 100 95-100 75-90 70-76 26-30 0.6-2.0 0.14-0.16 4.5-5.0 Moderate High ----- High.
100 100 95-100 85-95 40-45 15-20 0.6-2.0 0.10-0.14 7.9-8.4 Moderate Low ------ Low.
100 100 90-100 70-90 30-40 4-6 2.0-6.0 0.08-0.10 7.9-8.4 Low ------ Low ------ Low.
95-100 95-100 80-90 55-70 30-40 4-8 2.0-6.0 0.07-0.09 6.6-7.8 Low ------ Low ------ Low.
20-30 15-20 10-15 5-10 NP 1 NP >20.0 <0.05 6.6-7.8 Low ------ Low ------ Low.
100 100 90-100 75-95 70-90 25-40 0.6-2.0 0.12-0.15 4.5-5.5 Moderate-- High ----- High.
35-65 35-65 26-65 20-60 40-50 20-24 0.6-2.0 0.07-0.09 7.9-8.4 Low ------ High ----. Low.
90-100 75-100 70-99 65-90 70-85 45-50 0.06-0.2 0.15-0.18 7.9-9.0 High ---- High --_-- High.
100 100 90-100 75-95 75-85 50-60 0.06-0.2 0.15-0.18 6.1-7.8 High ----- High ----- Low.
85-100 85-100 75-85 60-80 70-80 35-45 0.6-2.0 0.13-0.16 7.9-8.4 High ---- High ----- Low.
85-100 85-100 75-85 60-80 40-60 10-30 0.6-2.0 0.13-0.16 7.9-8.4 Moderate -- Low ------ Low.
45-60 45-60 45-60 45-60 30-40 4-10 0.6-2.0 0.11-0.13 7.9-8.4 Low ------ Low ------ Low.

100 100 85-100 75-100 65-85 20-36 0.6-2.0 0.12-0.16 4.5-5.0 Moderate -- High ----- High.







100 100 90-100 65-95 30-40 15-20 0.6-2.0 0.08-0.10 6.6-7.8 Low ------ Low ----- Low.
55-85 50-80 25-75 20-60 20-30 5-10 >20.0 <0.05 6.6-7.3 Low ----- Low ------ Low.
100 100 90-100 70-95 65-75 30-40 0.2-0.6 0.12-0.14 7.4-7.8 High ---- High --- Low.
c








62 SOIL SURVEY

TABLE 7.-Estimated soil properties

Depth to- Classification
Coarse
Soil series Depth fraction
and Seasonal from USDA texture greater
map symbols Bedrock high surface Unified AASHTO than
water 3 inches
table

Feet Feet Inches

Juana Diaz: JzD, JzE -- 1-1.5 >5 0-12 Clay loam ------------------ ML, CL A-6 -
12-18 Silt loam ------------------ ML, CL-ML A-4
18 Semiconsolidated sandstone.
Lares: LeC ------------- >5 2.5-5.0 0-60 Clay ----------------------- MH A-7
Lirios: LmF2 ----------- >5 >5 0-28 Clay --------------------- MH A-7 -
28-60 Clay loam ----------------- ML, CL A-4 ---
Llanos: LnB, LnC2 ------- >5 >5 0-29 Clay ----------------------- CH A-7
29-50 Clay loam, sandy clay loam ---- CL, ML A-7
50-60 Sandy loam ---------------- SM-SC A-2, A-4 0
Los Guineos: LuE, LuF,
LyFX, LzFX. >5 >5 0-72 Clay ---------------------- MH A-7
Machuelo: Ma ---------- >5 1.5-3 0-60 Clay -------------------- CH A-7
Maraguez: MeF2 -------- >5 >5 0-12 Silty clay loam, clay loan ----. MH A-7
12-60 Loam -------------------- ML A-4 -
Maricao: MkF2 ---------- >5 >5 0-60 Clay ------------ ----- MH A-7
Meros: Mr ------------ >5 >5 0-60 Sand ---------------------- SP-SM, SM A-3, A-2
Montegrande: MsC ------ >5 2.5-5 0-25 Clay -------------------- CH A-7
25-60 Gravelly clay -------------- GM-GC A-2
Morado: MtE2, MtF2 ----- 1.5-3 >5 0-30 Clay loam ----------------- CL A-7
30 Semiconsolidated volcanic rock.
Mucara: MuD2, MuE2,
MuF2 ------------- 2-3 >5 0-19 Silty clay ------------------- MH, CH A-7
19-30 Weathered volcanic rock.
30 Semiconsolidated volcanic rock.
Paso Seco: PaB ------ >5 >5 0-32 Clay ---- ------------- CH A-7
32-60 Gravelly loam --------------- GM A-1 10-40
Pellejas: PeF2 --------- >5 >5 0-15 Clay loam ------------------- CL A-7
15-60 Loamy sand ---------------- SM A-2
Quebrada: QeD2, QeE2,
QeF2 ----------- >5 >5 0-14 Silty clay loam, silty clay -- M MH A-7 0-10
14-60 Silty clay loam ----------- CL A-6 -
Reilly: Re -------- >5 2.5-5 0-8 Gravelly loam ------------ GM A-2 0-5
8-60 Sand and gravel ----------- --GP A-1 0-20
Riverwash: Rw.
Properties too variable
to be estimated.
San Anton: Sa ---------- >5 >5 0-34 Clay loam, silty clay loam ---- CL A-6
34-60 Silt loam, loam --------------- CL A-4 -
Serrano: Se ----------- >5 2.5-3.5 0-21 Sandy loam ----------- SM A-2 -
21-60 Sand ------------------ SW-SM, SM A-2
Teresa: Te ----------- >5 2.5-3.5 0-50 Clay, silty clay loam---------- CH, MH A-7


Properties too variable
to be estimated.








PONCE AREA OF SOUTHERN PUERTO RICO 63

significant in engineering-Continued

Percentage passing sieve- Corrosivity to-
Available Shrink-
Liquid Plasticity Perme- water Reacon swell
No. 4 No. 10 No. 40 No. 200 limit index ability capacity potential Uncoated Concrete
(4.7 (2.0 (0.42 (0.074 steel
mm) mm) mm) mm)

Inches per Inches per PH
hour inch of soil

100 100 90-100 70-80 30-45 10-20 0.6-2.0 0.07-0.09 6.6-7.3 Low ------ Low ------ Low.
100 100 90-100 70-90 25-30 4-8 2.0-6.0 0.07-0.09 7.4-7.8 Low ----- Low ---- Low.

100 100 90-100 75-95 55-70 15-25 0.6-2.0 0.09-0.11 4.5-5.5 Moderate -- High. ---- High.
100 100 90-100 75-95 60-70 20-29 0.6-2.0 0.10-0.14 4.5-5.0 Moderate-_ High ---- High.
100 100 90-100 70-90 30-40 10-15 2.0-6.0 0.07-0.10 4.5-5.0 Low ------ High ----- High.
90-100 85-100 80-90 65-85 60-70 30-40 0.2-0.6 0.13-0.16 6.6-7.3 High ----- High ----- Low.
90-100 85-100 75-85 50-60 40-45 15-20 0.2-0.6 0.13-0.16 7.4-7.8 Moderate-- Moderate Low.
100 100 60-70 20-40 10-20 4-6 2.0-6.0 0.03-0.05 7.4-7.8 Low ------ Low ------ Low.

100 100 95-100 75-95 55-70 11-20 0.6-2.0 0.12-0.15 4.5-5.5 Moderate-- High ----- High.
100 100 90-100 75-95 60-100 30-50 0.06-0.2 0.13-0.16 7.4-8.4 High ---- High ----- Low.
100 100 95-100 85-95 50-60 20-30 0.6-2.0 0.09-0.11 5.6-6.5 Moderate Low ------ Low.
100 100 85-95 60-75 35-50 6-15 2.0-6.0 0.08-0.10 5.6-6.5 Low ---- Low ---- Low.
100 100 90-100 75-95 60-75 25-30 0.6-2.0 0.14-0.16 4.5-5.0 Moderate-- High --- High.
100 100 50-70 5-15 NP NP >20.0 <0.05 6.6-8.4 Low ------ Low ------ Low.
100 100 90-100 75-95 70-80 50-60 0.2-0.6 0.15-0.17 5.1-6.5 High ----- High -----Low.
45-55 45-55 35-45 30-35 28-32 10-15 0.6-2.0 0.10-0.12 7.4-8.4 Moderate- Moderate- Low.
100 100 90-100 70-80 40-50 20-30 0.6-2.0 0.11-0.13 6.1-7.3 Moderate-- Moderate-- Low.


100 100 90-100 80-90 60-75 30-35 0.6-2.0 0.15-0.17 5.6-6.5 High ----- High ----- Low.


90-100 90-100 80-90 65-85 55-60 40-45 0.06-0.2 0.15-0.18 6.6-7.8 High ----- High ----- Low.
40-65 40-65 25-50 12-20 NP NP 2.0-6.0 0.06-0.08 7.4-7.8 Low ------ Low ----- Low.
100 100 90-100 70-80 40-50 20-30 2.0-6.0 0.11-0.15 4.5-5.5 Low ----- Low ------ High.
100 100 50-75 15-30 NP NP 6.0-20.0 0.06-0.08 4.5-5.5 Low ------ Low --- High.

90-100 80-100 80-95 80-95 55-65 15-25 0.6-2.0 0.12-0.14 5.6-7.3 Moderate-- Moderate- Low.
90-100 90-100 80-95 75-85 30-40 12-25 0.6-2.0 0.12-0.14 5.6-7.3 Low ------ Moderate-- Low.
40-70 60-70 50-70 20-50 32-40 4-8 2.0-6.0 0.06-0.07 5.6-6.5 Low ---- Low ------ Moderate.
25-40 20-40 5-10 0-4 NP NP >20.0 <0.05 5.6-6.5 Low ----- Low ------ Moderate.




90-95 85-90 75-90 60-85 30-40 15-20 0.6-2.0 0.11-0.14 6.6-8.4 Moderate -- Low ------ Low.
100 100 85-100 60-90 20-30 5-10 2.0-6.0 0.09-0.11 6.6-8.4 Low ------ Low ---- Low.
90-95 85-90 50-65 25-35 5-10 NP 6.0-20.0 0.04-0.05 9.0-10.0 Low ------ High ----- Low.
90-95 85-90 40-65 5-15 NP NP >20.0 <0.05 9.0-10.0 Low ---- High ----- Low.
100 100 90-100 75-95 65-75 35-45 0.2-0.6 0.10-0.14 9.0-10.0 High ----- High ---- Low.
100 100 50-70 10-40 NP NP 6.0-20.0 <0.05 8.5-9.0 Low ------ High --- Low.







64 SOIL SURVEY

TABLE 7.-Estimated soil properties

Depth to- Classification
Coarse
Soil series Depth fraction
and Seasonal from USDA texture greater
map symbols Bedrock high surface Unified AASHTO than
water inches
table

Feet Feet Inches

Toa: To --------------- >5 2.5-5 0-60 Silty clay loam, clay loam ----- CL A-7
Tuque: TuF ------------ >5 >5 0-11 Gravelly clay -------------- GC A-6 25-40
11-19 Hard caliche.
19-60 Gravelly limestone.
Yauco: YcB, YcC -------- >5 >5 0-21 Silty clay loam ----------- ML, CL A-7 0-10
21-60 Soft limestone --------------- ML, CL A-4 0-25

NP means nonplastic.

shrinks as it dries out or swells when it gets wet. Ex- come. Moderate indicates that some soil properties are
tent of shrinking and swelling is influenced by the unfavorable but can be overcome or modified by special
amount and kind of clay in the soil. Shrinking and planning and design. Severe indicates that soil proper-
swelling of soils causes much damage to building ties are so unfavorable and so difficult to correct or
foundations, roads, and other structures. A high overcome that major soil reclamation and special de-
shrink-swell potential indicates a hazard to the main- signs are required.
tenance of structures built in, on, or with material Soil suitability is rated by the terms good, fair, and
having this rating. poor, which have meanings approximately parallel to
Corrosivity pertains to potential soil-induced chemi- the terms slight, moderate, and severe.
cal action that dissolves or weakens uncoated steel or Following are explanations of some of the columns in
concrete. Rate of corrosion of uncoated steel is related table 8.
to soil properties such as drainage, texture, total Septic tank absorption fields are subsurface systems
acidity, and electrical conductivity of the soil material, of tile or perforated pipe that distribute effluent from
Corrosivity for concrete is influenced mainly by the a septic tank into natural soil. The soil material from
content of sodium or magnesium sulfate, but also by a depth of 18 inches to 6 feet is evaluated. The soil
soil texture and acidity. Installations of uncoated steel properties considered are those that affect both absorp-
that intersect soil boundaries or soil horizons are more tion of effluent and construction and operation of the
susceptible to corrosion than installations entirely in system. Properties that affect absorption are perme-
one kind of soil or in one soil horizon. A corrosivity ability, depth to water table or rock, and susceptibility
rating of low means that there is a low probability of to flooding. Slope affects layout and construction and
soil-induced corrosion damage. A rating of high means also the risk of soil erosion, lateral seepage, and down-
that there is a high probability of damage and that slope flow of effluent. Large rocks or boulders increase
protective measures for steel and more resistant con- construction costs.
create should be used to avoid or minimize damage. Sewage lagoons are shallow ponds constructed to
hold sewage, within a depth of 2 to 5 feet, long enough
Engineering interpretations of the soils for bacteria to decompose the solids. A lagoon has a
nearly level floor; its sides, or embankments, are of
The estimated interpretations in table 8 are based soil material compacted to medium density, and the
on the engineering properties of the soils shown in pond is protected from flooding. Properties that affect
table 7, on test data for soils in this survey area and the pond floor are permeability, organic matter con-
others nearby or adjoining, and on the experience of tent, and slope; if the floor needs to be leveled, depth to
engineers and soil scientists with the soils in the Ponce bedrock is a concern. The soil properties that affect
Area. In table 8, ratings are used to summarize limita- the embankment are the engineering properties of the
tions or suitability of the soils for all listed purposes embankment material as interpreted from the Unified
other than for drainage of cropland and pasture, irri- system and the amounts of stones, if any, that in-
gation, ponds and reservoirs, embankments, and ter- fluence the ease of excavation and compaction of the
races and diversions. For these particular uses, table 8 embankment material.
lists those soil features not to be overlooked in plan- Shallow excavations are those that require digging
ning, installation, and maintenance, or trenching to a depth of less than 6 feet, for example,
Soil limitations are indicated by the ratings slight, excavations for pipelines, sewer lines, phone and power
moderate, and severe. Slight indicates that soil prop- transmission lines, basements, open ditches, and ceme-
erties generally are favorable for the rated use, or in teries. Desirable soil properties are good workability,
other words, the limitations are minor and easily over- moderate resistance to sloughing, gentle slopes, absence







PONCE AREA OF SOUTHERN PUERTO RICO 65

significant in engineering-Continued

Percentage passing sieve- Corrosivity to-
Liquid Plasticity Perme- Available Shrink-
No. 4 No. 10 No. 40 No. 200 limit index ability water Reaction swell
(4.7 (2.0 (0.42 (0.074 capacity potential Uncoated Concrete
(4.7 (2.0 (0.42 (0.074 steel Concrete
mm) mm) mm) mm)

Inches per Inches per pH
hour inch of soil
100 100 95-100 85-95 40-45 16-21 0.6-2.0 0.12-0.14 6.1-6.5 Moderate Moderate Low.
40-65 40-60 40-50 40-50 30-50 10-20 6.0-20.0 0.07-0.09 7.9-8.4 Low High -----Low.


95-100 95-100 85-95 70-90 40-45 15-25 0.6-2.0 0.14-0.18 7.9-8.4 Moderate Moderate-- Low.
95-100 95-100 95-100 70-95 25-35 5-15 2.0-6.0 0.10-0.13 7.9-8.4 Low.



of rock outcrops or large stones, and freedom from rial and the shrink-swell potential indicate traffic-
flooding or absence of a high water table. supporting capacity. Wetness and flooding affect
Dwellings without basements, as rated in table 8, stability of the material. Slope, depth to hard rock,
are not more than three stories high and are supported content of stones and rocks, and wetness affect ease
by foundation footings placed in undisturbed soil. The of excavation and amount of cut and fill needed to
features that affect the rating of a soil for dwellings reach an even grade.
are those that relate to capacity to support load and Roadfill is soil material used in embankments for
resist settlement under load and to ease of excavation, roads. The suitability ratings reflect (1) the predicted
Soil properties that affect capacity to support load are performance of soil after it has been placed in an em-
wetness, susceptibility to flooding, density, plasticity, bankment that has been properly compacted and pro-
texture, and shrink-swell potential. Those that affect vided with adequate drainage and (2) the relative ease
excavation are wetness, slope, depth to bedrock, and of excavating the material at borrow areas.
content of stones and rocks. Sand and gravel are used in great quantities in many
Sanitary landfill is a method of disposing of refuse kinds of construction. The ratings in table 8 provide
in dug trenches. The waste is spread in thin layers, guidance about where to look for probable sources. A
compacted, and covered with soil. Landfill areas are soil rated as a good or fair source generally has a layer
subject to heavy vehicular traffic. Some soil properties of sand or gravel at least 3 feet thick, the top of which
that affect suitability for landfill are ease of excava- is within a depth of 6 feet. The ratings do not take into
tioh, hazard of polluting ground water, and trafficabil- account thickness of overburden, location of the water
ity. The best soils have moderately slow permeability, table, or other factors that affect mining of the ma-
withstand heavy traffic, and are friable and easy to trials, nor do they indicate quality of the deposit.
excavate. Unless otherwise stated, the ratings in table Topsoil is used for topdressing an area where vege-
8 apply only to the soil material to a depth of about station is to be established and maintained. Suitability
6 feet, so a limitation of slight or moderate may not be is affected mainly by ease of working and spreading
valid if trenches are to be much deeper than that. For the soil material, as in preparing a seedbed; natural
some soils, reliable predictions can be made to a depth fertility of the material or plant response when fer-
of 10 or 15 feet; nevertheless, every site should be tilizer is added to the soil; and absence of substances
investigated before it is selected. toxic to plants. Texture of the soil material and its
Local roads and streets, as rated in table 8, have an content of stone fragments affect suitability. Also con-
all-weather surface expected to carry automobile traf- sidered in the ratings is damage that will result at the
fic all year. They have a subgrade of underlying soil area from which topsoil is taken.
material; a base consisting of gravel, crushed rock, or Pond reservoir areas hold water behind a dam or
soil material stabilized with lime or cement; and a embankment. Soils suitable for use as pond reservoir
flexible or rigid surface, commonly asphalt or concrete. areas have low seepage, which is related to their per-
These roads are graded to shed water and have or- meability and depth to fractured or permeable bedrock
dinary provisions for drainage. They are built mainly or other permeable material.
from soil at hand, and most cuts and fills are less than Dikes, levees, and embankments require soil material
6 feet deep. that is resistant to seepage and piping and that is of
Soil properties that most affect design and construc- favorable stability, shrink-swell potential, shear
tion of roads and streets are load-supporting capacity strength, and compactability. Stones or organic ma-
and stability of the subgrade and the workability and trial in a soil are among factors that are unfavorable.
quantity of cut and fill material available. The Drainage of cropland and pasture is affected by such
AASHTO and Unified classifications of the soil mate- soil properties as permeability, texture, and structure;









66 SOIL SURVEY

TABLE 8.-Interpretations of

Degree and kind of limitation for-

Soil series and map symbols Septic tank Shallow Dwellings Sanitary Local roads
absorption Sewage Shallow without Sanitary
fields lagoons excavations basements landfills and streets

Adjuntas: AaF2 ------------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope. slope, slope.



Aguilita: AgD, AgF, AhF ---- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, mod- slope, slope, moderate slope,
erate per- stones. stones. perme- stones.
meability, ability,
coarse stones.
fragments.

Alonso: AnE2, AnF2 ---------- Severe: Severe: Severe: Severe: Moderate if Severe:
slope, slope. slope, slope, slope is slope.
12 to 25
percent.
Severe if
more than
25 percent.

Caguabo: CbF2, CdF -------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, shal- slope, shal- slope, slope, slope, slope,
low to hard low to shallow to shallow to shallow to shallow to
rock. bedrock, bedrock, bedrock, bedrock. bedrock.

Callabo: CoD, CoE, CoF2 ----- Severe: Severe: mod- Severe: Severe: Severe: Severe:
slope, mod- erately slope, slope, moderately slope.
erately deep deep to bed- moderately deep to
to hard rock, slope, deep to bedrock,
rock. bedrock, slope.
Cintrona: Cr ------------ Severe: Severe: Severe: Severe: Severe: Severe:
subject to subject to subject to subject to subject to poorly
flooding, flooding, flooding, flooding, flooding, drained,
very slow too clayey, poorly poorly subject to
permeabil- depth to drained, drained, flooding,
ity, depth water table, depth to too clayey. high
to water poorly water table, shrink-
table. drained, high swell
shrink-swell potential.
potential.

Constancia: C ------------- Severe: Severe: Severe: Severe: Severe: Severe:
slow per- flooding, somewhat somewhat somewhat somewhat
meability, poorly poorly poorly poorly
depth to drained, too drained, drained, drained,
water table, clayey. flooding, flooding, flooding,
flooding, high too clayey. high
shrink-swell shrink-
potential. swell
potential.


Consumo: CuF2 ------------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope, slope, slope.





Cortada: Cx -------------- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, flooding, flooding, flooding, flooding, flooding.
moderate
perme-
ability.









PONCE AREA OF SOUTHERN PUERTO RICO 67

engineering properties of the soils

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Poor: slope Unsuited -- Poor: slope Moderate Shallow to Well drained Not needed -- Not needed.
perieabil- partly
ity, slope, weathered
volcanic
rock.

Fair: 15 to Unsuited --- Poor: slope, Moderate Slope, stones, Well drained Not needed -- Not needed.
25 percent coarse permeabil- poor
slopes, fragments, ity, slope, compaction.
Poor: thin layer. seepage,
25 percent stones.
slopes.
Poor: high Unsuited -- Poor: slope, Slope, moder- High com- Well drained Not needed Not needed.
clay con- high clay ate perme- pressibility,
tent. content. ability, slope.




Poor: slope, Unsuited -- Poor: slope, Moderate Shallow to Well drained Not needed Not needed.
shallow to coarse permeabil- bedrock.
bedrock. fragments, ity, shallow
thin layer. to bedrock,
slope.

Poor: slope Unsuited -- Poor: slope Permeability, Moderately Well drained Not needed Notneeded.
moderately deep to
deep to bedrock,
bedrock, fair to poor
slope, compaction.

Poor: high Unsuited -- Poor: Depth to High shrink- Depth to Drainage Not needed.
shrink- poorly water swell poten- water table, needed,
swell drained, table. tial, high flooding, depth to
potential, too clayey. compress- slow per- water table.
poorly ibility, meability.
drained, fair to poor
compaction.



Poor: Unsuited -- Poor: too Depth to High shrink- Slow per- Need for Clayey
high clay clayey, water swell poten- meability, drainage, texture,
content, somewhat table. tial, high depth to depth to slow per-
high poorly compress- water table, water table, meability.
shrink- drained. ibility, poor flooding.
swell compaction.
potential,
somewhat
poorly
drained.
Poor: slope Unsuited _- Poor: slope Moderate High com- Well drained Not needed Not needed.
permeabil- pressibility,
ity, slope, poor
seepage, compaction,
susceptibil-
ity to
piping.

Fair: clay Unsuited -- Good ------- Moderate High sus- Well drained All features All features
content, permeabil- ceptibility favorable. favorable.
moderate ity. to piping,
shrink- fair to poor
swell compaction.
potential.








68 SOIL SURVEY

TABLE 8.-Interpretations of engineering

Degree and kind of limitation for-

Soil series and map symbols Septic tank Dwellings
absorption Sewage Shallow with Sanitary Local roads
fields lagoons excavations basements landfills and streets

Cuyon: CyB --------------- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, very rapid flooding, flooding, very rapid flooding.
potential perme- texture of permeabil-
pollution ability, substratum, ity, texture
of ground flooding, of sub-
water. potential stratum.
pollution
of ground
water.
Daguey: DaD ---- ------ Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope, too clayey, slope.


Ensenada: EnC -------------Slight if slope Severe: Severe: Slight if slope Severe: Slight if
is 2 to 8 moderate substratum is 2 to 8 substratum slope is
percent, perme- too clayey. percent. too clayey. 2 to 8
Moderate if 8 ability. Moderate if percent.
to 12 per- 8 to 12 Moderate if
cent. percent. 8 to 12
percent.
Fe: Fe ------------ --- Severe: Severe: Severe: Severe: Severe: Severe:
slow per- flooding, somewhat flooding, flooding, flooding,
meability, poorly high soil high
flooding, drained, shrink- texture, shrink-
flooding, swell swell
too clayey. potential, potential.

Fraternidad: FtB, FtC2 ---- Severe: Moderate if Severe: too Severe: Severe: Severe:
slow per- slope is 2 clayey. high too clayey. high
meability. to 7 per- shrink- shrink-
cent; severe swell swell
if slope is potential, potential.
more than
7 percent.
Guanabano: GoF------------ Severe: Severe: Severe: Severe: Severe: Severe:
slope. slope, slope, slope, slope, slope.


Humatas: HmE2, HmF2, HxF -- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope. slope, slope. clayey slope.
texture,
slope.


Hydraquents: Hy.
Material too variable for
interpretations.
Hydraquents, saline: Hz --- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, depth to depth to depth to very very poorly
depth to water table, water table, water table, poorly drained,
water table, flooding, flooding. flooding, drained, flooding.
flooding.
Jacaguas: Jg ----------- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, rapid per- flooding, flooding, flooding, flooding.
pollution meability, texture of rapid per-
hazard. flooding, substratum, meability,
texture of
substratum.








PONCE AREA OF SOUTHERN PUERTO RICO 69

properties of the soils-Continued

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Good -------- Fair .----- Poor: coarse Very rapid Shallow to Excessively Available Not needed.
fragments, permeabil- gravel, very drained, water ca-
thin layer, ity, seepage. rapid per- pacity, very
meability, rapid per-
susceptibil- meability,
ity to depth of
piping. soil.


Poor: high Unsuited -Poor: too Moderate High corn- Well drained Not needed -- Not needed.
clay con- clayey. permeabil- pressibility,
tent. ity, slope, poor
compaction.

Good -------- Poor ---- Poor: coarse Seepage ----- Susceptibility Well drained Slope ------ Slope, stones,
fragments. to piping. depth to
unfavorable
material.




Poor: Unsuited -Poor: clay All features Salinity and Slow per- Need for Not needed.
high clay texture, favorable, alkalinity, meability, drainage,
content, soluble high cor- salinity, salinity,
high salts. pressibility, alkalinity, alkalinity.
shrink- fair to poor
swell compaction.
potential.
Poor: high Unsuited -Poor: high All features High cor- Slow per- Slope-------- Slope, clayey
shrink- clay favorable. pressibility, meability. texture,
swell content. poor slow per-
potential. compaction, meability.
high shrink-
swell
potential.

Poor: slope Unsuited Poor: slope, Moderate Poor corn- Well drained Not needed Not needed.
coarse permeabil- action.
fragments. ity, seepage,
slope.

Poor: Unsuited -- Poor: clayey Moderate Fair to poor Well drained Not needed Not needed.
high clay texture, permeabil- compaction,
content, slope, ity, slope. high sus-
slope. ceptibility
to piping.





Poor: very Unsuited -Poor: very Not needed -- Not needed -- Depth to Need for Not needed.
poorly poorly water table, drainage.
drained, drained, salinity,
soluble alkalinity.
salts.

Good -------- Fair-------- Fair: soil Rapid Shallow to Excessively Rapid per- Not needed.
texture, permeabil- gravel, high drained, meability,
thin layer. ity, seepage. perme- depth of
ability, sus- soil.
ceptibility
to piping.








70 SOIL SURVEY

TABLE 8.-Interpretations of engineering

Degree and kind of limitation for-

Soil series and map symbols Septic tank Sewage Shallow Dwellings Sanitar Local ads
absorption Sewa Shallow without y Local roads
absorptionelds lagoons excavations wbas nts landfills and streets
fields basements

Jacana: JnC --------------- Severe: Severe: Severe: Severe: Severe: Severe:
depth to depth to depth to high depth to shrink-
bedrock, bedrock, bedrock, shrink- bedrock, swell
moderately swell too clayey. potential.
slow per- potential.
meability.
Juana Diaz: JzD, JzE -------- Severe: Severe: Severe: Severe: Severe: Severe:
shallow to slope, slope, slope, shallow to slope,
bedrock, shallow to shallow to shallow to bedrock, shallow to
slope, bedrock, bedrock, bedrock, bedrock.


Lares: LeC ---------------- Moderate: Moderate: Moderate: Moderate: Severe: Moderate:
moderate moderate drainage, shrink- too clayey. shrink-
perme- perme- too clayey. swell swell
ability, ability, potential, potential.
Moderate if
slope is 2 to
7 percent.
Severe if
more than
7 percent.
Lirios: Lm F2 ---------------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope, slope, slope.


Llanos: LnB, LnC2 ----------- Moderate: Severe: Slight if slope Severe: high Severe: Severe:
moderately moderately is 2 to 8 shrink- moderately high
slow per- slow per- percent; swell slow per- shrink-
meability, meability of moderate if potential, meability of swell
potential substratum, 8 to 12 substratum, potential.
pollution of potential percent. potential
ground pollution pollution
water, of ground of ground
water. water.
Los Guineos: LuE, LuF, LyFX, Severe: Severe: Severe: Severe: Moderate if Severe:
LzFX. slope. slope, slope. slope, slope is slope.
For Maricao part of 15 to 25
LyFX and LzFX, see percent;
Maricao series. No severe if
interpretations for more than
Stony rock land part 25 percent.
of LzFX.
Machuelo: Ma ------------- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, flooding, flooding, poorly depth to poorly
slow per- depth to drained, water table, drained,
meability, water table, depth to flooding, flooding,
depth to too clayey. water table, too clayey. shrink-
water table. flooding, swell
shrink- potential.
swell
potential.
Maraguez: MeF2 ------------Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope, slope, slope.



Maricao: MkF2------------- Severe: Severe: Severe: Severe: Severe: Severe:
slope. slope, slope, slope, slope, slope.








PONCE AREA OF SOUTHERN PUERTO RICO 71

properties of the soils-Continued

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Poor: high Unsuited -- Poor: high Depth to High cor- Well drained Slope, hazard Slope, depth
shrink- clay bedrock, pressibility, of erosion, to bedrock.
swell content. shallow to
potential, bedrock.
high clay
content.
Fair if slope Unsuited -- Poor: slope- Shallow to Slope, shallow Well drained Not needed -- Not needed.
is 15 to 25 bedrock. to bedrock.
percent;
poor if
more than
25 percent.
Fair: shrink Unsuited -- Poor: too Moderate High cor- All features Not needed Slope.
swell clayey, perme- pressibility, favorable.
potential. ability. poor
compaction.






Poor: slope- Unsuited -- Poor: slope Moderate Susceptibility Well drained Not needed Not needed.
permeabil- to piping,
ity, slope, fair to poor
seepage. compaction.

Poor: high Unsuited -Poor: too Moderately High shrink- Compress- Slope, moder- Slope,
shrink- clayey. slow perme- swell ibility, soil ately slow depth to
swell ability, potential. compaction. perme- unfavorable
potential. seepage. ability in material,
substratum. texture.




Poor: high Unsuited -- Poor: slope, Slope, moder- High com- Slope-------- Not needed -- Not needed.
clay high clay ate perme- pressibility,
content. content. ability, slope.





Poor: high Unsuited --- Poor: clayey Depth to High shrink- Slow per- Need for Texture,
clay texture, water table. swell meability, drainage, slow per-
content, poorly potential, depth to depth to meability.
shrink- drained, high com- water table, water table.
swell pressibility, flooding,
potential, fair to poor ponding.
poorly compaction.
drained.

Poor: slope- Unsuited --- Poor: slope Slope, moder- High sus- Well drained -Not needed- Not needed.
ate perme- ceptibility
ability, to piping,
fair to poor
compaction.

Poor: slope, Unsuited -- Poor: slope, Moderate High com- Well drained Not needed Not needed.
high clay too clayey. permeabil- pressibility,
content. ity, slope. poor
compaction.








72 SOIL SURVEY

TABLE 8.-Interpretations of engineering

Degree and kind of limitation for-

Soil series and map symbols Sepc t tank Dw e
Soil series and ma symbols Septic tank Sewage Shallow Dwellings Sanitary Local roads
absfrtion lagoons excavations basei ts landfills and streets
fields basements

Meros: Mr ---------------- Severe: Severe: Severe: Slight ------- Severe: very Slight -_-
very rapid very sandy rapid per-
perme- rapid per- texture, meability,
ability, meability, sidewall pollution
pollution pollution stability, hazard.
hazard. hazard.
Montegrande: MsC ----------Severe: per- Moderate if Severe: too Severe: Severe: soil Severe:
meability. slope is 2 clayey. high texture, high
to 7 per- shrink- shrink-
cent; severe swell swell
if slope is potential, potential,
7 to 12 high clay
percent. content.

Morado: M+E2, MtF2 -------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, shallow to slope, slope, shallow to slope.
bedrock, shallow to bedrock.
slope, bedrock.



Mucara: MuD2, MuE2, MuF2 Severe: Severe: Severe: Severe: Severe: Severe:
slope, shal- slope, slope, slope, shallow to slope.
low to hard shallow to shallow to bedrock.
rock. hard rock. hard rock.


Paso Seco: PaB ------------- Severe: Severe: Severe: clay Severe: Severe: clay Severe: high
slow per- slow per- texture, high texture. shrink-
meability, meability shrink- swell
pollution of sub- swell potential.
hazard, stratum, potential.
pollution
hazard.

Pellejas: PeF2 -------------- Severe: Severe: Severe: Severe: Severe: Severe:
slope, slope, slope, slope, slope, slope.
moderately moderately
rapid per- rapid per-
meability. meability.
Quebrada: QeD2, QeE2, QeF2 Severe: Severe: Severe: Severe: Moderate if Severe:
slope, slope, slope, slope, slope is slope.
15 to 25
percent;
severe if
more than
25 percent.
Reilly: Re ----------------- Severe: Severe: Severe: Severe: Severe: Severe:
flooding, very flooding, flooding, flooding, flooding.
depth to slow per- gravelly very
water table, meability, substratum, slow per-
pollution depth to meability,
hazard, water table, pollution
flooding, hazard.
pollution
hazard.
Riverwash: Rw ------------ Severe: Severe: Severe: Severe: Severe: Severe:
flooding, flooding, depth to depth to flooding, flooding,
depth to depth to water table, water table, stones. stones.
water table, water table, flooding, flooding.
stones, coarse stones.
fragments.









PONCE AREA OF SOUTHERN PUERTO RICO 73

properties of the soils-Continued

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Good ------ Fair: sand- Poor: sandy Not needed -- Not needed -- Excessively Not needed Not needed.
texture. drained.




Poor: high Unsuited -- Poor: too Moderately High shrink- Moderately Not needed -- Slope, too
clay con- clayey. slow perme- swell slow per- clayey,
tent, high ability, potential. meability, moderately
shrink- slope, too slow per-
swell clayey. meability,
potential, depth to
unfavorable
material.

Poor: Unsuited ___ Poor: slope Moderate Shallow to Well drained Not needed -- Not needed.
thickness of permeabil- bedrock,
suitable ity, shallow high sus-
material, to bedrock, ceptibility
slope, to piping,
fair to poor
compaction.

Fair if slope Unsuited Poor: high Seepage Shallow to Well drained Not needed -- Not needed.
is 15 to 25 clay potential, bedrock,
percent; content, slope, slope.
severe if
more than
25 percent.

Poor: high Unsuited ___ Poor: too Moderately Compaction Permeability Slope -------- Slope, depth to
shrink- clayey. rapid per- character- is slow in unfavorable
swell meability istics, high surface material.
potential, below 32 shrink-swell layer and
inches. potential, moderately
rapid below
surface
layer.

Poor: slope Poor: Poor: slope Moderately Susceptibility Somewhat Not needed -- Not needed.
improbable rapid per- to piping, excessively
source, meability, medium drained.
seepage, strength.
slope.

Fair if slope Unsuited __ Poor: slope- Moderate Susceptibility Well drained Not needed -- Not needed.
is 15 to 25 permeabil- to piping,
percent; ity, seepage, fair to poor
severe if slope. compaction.
more than
25 percent.

Good -------- Good: Poor: thick- Not needed -- Not needed __ Excessively Available Not needed.
gravel. ness of drained, water ca-
material, pacity,
coarse depth of
fragments, soil, rate
of water
intake.



Fair: Good for Poor: Not needed Not needed Excessively Not needed -- Not needed.
stones, gravel, stones, drained.
coarse
fragments.








74 SOIL SURVEY

TABLE 8.-Interpretations of engineering

Degree and kind of limitation for-

Soil series and map symbols Septic tank Sewage Shallow Dwellings Sanitary Local roads
absorption lagoons excavations without landfills and streets
fields basements

San Anton: Sa ------------- Severe: Severe: Severe: Severe: Severe: Severe:
subject to subject to subject to subject to subject to subject to
flooding, flooding, flooding, flooding. flooding, flooding.


Serrano: Se ---------------- Severe: Severe: Severe: Severe: Severe: Severe:
depth to depth to poorly poorly poorly poorly
water table, water table, drained, drained, drained, drained,
flooding, rapid per- depth to flooding, flooding, flooding.
meability, water table, rapid per-
soluble flooding, meability,
salts, sandy sandy
flooding. texture. texture.

Teresa: Te ----------------- Severe: Severe: Severe: Severe: Severe: Severe:
depth to depth to somewhat flooding, depth to flooding.
water table, water table, poorly water table,
flooding, flooding, drained, flooding.
depth to
water table,
flooding.
Tidal flats: Tf.
Soil material too variable
for interpretations.
Toa: To ------------------- Severe: Severe: Severe: Severe: Severe: Severe:
subject to subject to subject to subject to subject to subject to
flooding. flooding. flooding, flooding. flooding, flooding.


Tuque: TuF ---------------- Severe: Severe: Severe: Severe: Severe: Severe:
stones, slope, slope, slope, shallow to slope,
slope, shal- coarse shallow to stones, bedrock, shallow to
low to fragments, bedrock, shallow to stones, bedrock,
hard rock. shallow to stones. bedrock, stones.
bedrock.
Yauco: YcB, YC ------------ Slight if slope Severe: Slight if slope Slight if Slight ------ Moderate:
is 2 to 8 moderate is 2 to 8 slope is Unified soil
percent; perme- percent; 2 to 8 group CL.
moderate ability, moderate if percent;
if 8 to 12 8 to 12 moderate
percent. percent. if 8 to 12
percent.


depth to claypan, rock, or other layers that influence constructed across the slope to intercept runoff so that
rate of water movement; depth to the water table; it soaks into the soil or flows slowly to a prepared out-
slope; stability in ditchbanks; susceptibility to stream let. Features that affect suitability of a soil for ter-
overflow; salinity or alkalinity; and availability of out- races are uniformity and steepness of slopes; depth to
lets for drainage, bedrock or to other unfavorable material; presence of
Irrigation of a soil is affected by such features as stones; permeability; and resistance to water erosion,
slope; susceptibility to stream overflow, water erosion, soil slipping, and soil blowing. A soil suitable for these
or soil blowing; soil texture; content of stones; ac- structures provides outlets for runoff and is not diffi-
cumulation of salts and alkali; depth of root zone; cult to vegetate.
rate of water intake at the surface; permeability be-
low the surface layer and in fragipans or other layers Engineering test data
that restrict movement of water; amount of water held Table 9 contains engineering test data for four soils
available to plants; and need for drainage, or depth to in the Ponce Area. The tests were made to help evalu-
water table or bedrock. ate the soils for engineering purposes. The engineering
Terraces and diversions are embankments, or ridges, classifications are based on data obtained by mechani-








PONCE AREA OF SOUTHERN PUERTO RICO 75

properties of the soils-Continued

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Fair: Unsuited -- Fair: soil Moderate to Susceptibility Well drained All features All features
moderate texture, moderately to piping. favorable, favorable.
shrink- rapid per-
swell meability,
potential, seepage.
Poor: Fair for Poor: Rapid per- Soluble salts Depth to Low available Not needed.
poorly sand. soluble meability, water table, water ca-
drained. salts, depth to stability of pacity, rate
poorly water table, ditchbanks, of water
drained soluble flooding and intake, need
sandy salts. ponding, for drain-
texture. salinity. age, salinity,
rapid per-
meability.

Poor: Unsuited -- Poor: Not needed Not needed Salinity ----- Salinity ----. Not needed.
high clay soluble
content, salts.
high
shrink-
swell
potential.



Fair: Unsuited --- Fair: Depth to Poor compac- All features Not needed -- All features
moderate consistence, water table, tion, high favorable, favorable.
shrink- too clayey. moderate susceptibil-
swell permeabil- ity to
potential. ity, seepage, piping.
Poor: Unsuited --- Poor: Shallow to Shallow to Well drained Not needed -- Not needed.
stones. coarse bedrock, bedrock,
fragments, slope, stones.
stones,
slope.

Fair: Unsuited --- Poor: high Moderate Compressibil- Well drained Slope, Slope, depth to
Unified calcium perme- ity strength, moderate unfavorable
soil group carbonate ability. susceptibil- perme- material.
CL. equivalent, ity to ability.
piping, fair
compaction.



cal analyses and by tests to determine liquid limit and sure the effect of water on the consistence of soil ma-
plastic limit. The mechanical analyses were made by trial, as has been explained for table 7.
combined sieve and hydrometer methods.
Compaction (or moisture-density) data are impor-
tant in earthwork. If a soil material is compacted at Formation, morphology, and
successively higher moisture contents, assuming that classification of the soils
the compactive effort remains constant, the density of
the compacted material increases until the optimum This section gives information about the formation,
moisture content is reached. After that, density de- morphology, and classification of the soils in the Ponce
creases with increase in moisture content. The highest Area.
dry density obtained in the compactive test is termed
maximum dry density. As a rule, maximum strength Factors of soil formation
of earthwork is obtained if the soil is compacted to the
maximum dry density. Soils are formed through the interaction of five ma-
Tests to determine liquid limit and plastic limit mea- jor factors. These factors are climate, plants and ani-








PONCE AREA OF SOUTHERN PUERTO RICO 75

properties of the soils-Continued

Suitability as a source of- Soil features affecting-

Sand Pond Dikes, Drainage Terraces
Roadfill and Topsoil reservoir levees, and for crops and Irrigation and
gravel areas embankments pasture diversions

Fair: Unsuited -- Fair: soil Moderate to Susceptibility Well drained All features All features
moderate texture, moderately to piping. favorable, favorable.
shrink- rapid per-
swell meability,
potential, seepage.
Poor: Fair for Poor: Rapid per- Soluble salts Depth to Low available Not needed.
poorly sand. soluble meability, water table, water ca-
drained. salts, depth to stability of pacity, rate
poorly water table, ditchbanks, of water
drained soluble flooding and intake, need
sandy salts. ponding, for drain-
texture. salinity. age, salinity,
rapid per-
meability.

Poor: Unsuited -- Poor: Not needed Not needed Salinity ----- Salinity ----. Not needed.
high clay soluble
content, salts.
high
shrink-
swell
potential.



Fair: Unsuited --- Fair: Depth to Poor compac- All features Not needed -- All features
moderate consistence, water table, tion, high favorable, favorable.
shrink- too clayey. moderate susceptibil-
swell permeabil- ity to
potential. ity, seepage, piping.
Poor: Unsuited --- Poor: Shallow to Shallow to Well drained Not needed -- Not needed.
stones. coarse bedrock, bedrock,
fragments, slope, stones.
stones,
slope.

Fair: Unsuited --- Poor: high Moderate Compressibil- Well drained Slope, Slope, depth to
Unified calcium perme- ity strength, moderate unfavorable
soil group carbonate ability. susceptibil- perme- material.
CL. equivalent, ity to ability.
piping, fair
compaction.



cal analyses and by tests to determine liquid limit and sure the effect of water on the consistence of soil ma-
plastic limit. The mechanical analyses were made by trial, as has been explained for table 7.
combined sieve and hydrometer methods.
Compaction (or moisture-density) data are impor-
tant in earthwork. If a soil material is compacted at Formation, morphology, and
successively higher moisture contents, assuming that classification of the soils
the compactive effort remains constant, the density of
the compacted material increases until the optimum This section gives information about the formation,
moisture content is reached. After that, density de- morphology, and classification of the soils in the Ponce
creases with increase in moisture content. The highest Area.
dry density obtained in the compactive test is termed
maximum dry density. As a rule, maximum strength Factors of soil formation
of earthwork is obtained if the soil is compacted to the
maximum dry density. Soils are formed through the interaction of five ma-
Tests to determine liquid limit and plastic limit mea- jor factors. These factors are climate, plants and ani-




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