Studies on the physico-chemical characteristics of some Florida soils

Material Information

Studies on the physico-chemical characteristics of some Florida soils
Pavageau, Moacyr
Place of Publication:
Gainesville FL
University of Florida
Publication Date:
Physical Description:
40 leaves : ill. ; 29 cm.


Subjects / Keywords:
Adsorption ( jstor )
Ions ( jstor )
Moisture content ( jstor )
Pressure ( jstor )
Soil horizons ( jstor )
Soil moisture ( jstor )
Soil organic matter ( jstor )
Soil water ( jstor )
Soils ( jstor )
Water pressure ( jstor )
Dissertations, Academic -- Soil Science -- UF
Soil Science thesis, M.S
Soil chemistry -- Florida ( lcsh )
Soils -- Florida ( lcsh )
bibliography ( marcgt )
non-fiction ( marcgt )


Thesis (M.S) -- University of Florida, 1943.
Includes bibliographical references (leaves 37-38).
General Note:
General Note:
Statement of Responsibility:
by Moacyr Pavageau.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright Moacyr Pavageau. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
029886286 ( ALEPH )
33379788 ( OCLC )
ACF4046 ( NOTIS )

Full Text




July, 1943



i ItrOduotixon* ********************************* ********* 1

Il* Literature Revieweo...o**********oo******oo ******* ***o o**

IlIZ Plan of Inve tiegatiooB,* ****...*************************

I V Methods of Prooedurefo.......ooooo.****************** ** 10

To Presentation of Results and Disoussionooooo*............ 12

VIo Sum mry nd Conolusioa Booooo. eo*********************** M4

VIIZ Literattur Cit**dooooooooo.**********.o *...******oo.. ... 87

15 4S~j


The writer takes pleasure in aoknowledring the may

helpful suggestions of Dr. PF 8. Smith during the progress of

this work and for readin! the manuscript. The assistance of

Dr. C. E. Bell and Prof. J, R. Henderson is also Lratefully


Studies on the physioo-cheaiol oharacteristies
of soam Florida Soils


The colloidal fraction is the most important portion of the

soil* Indeed, all intake phenomena of plants depend on it* The ooarse

fractions of the soil form the skeleton or framework, whereas the ool-

loidal particles constitute the active part, important in the mineral

nutrition of plants.

The dynamics of soil are based almost entirely on colloidal

ohemistry. With the development of this branch of silence the interrre-

lationships between plant and soil may be better understood* The old

concept that the soil is station is no longer tenable* The modern con-

cept holds that plant and soil are in continuous dynamics equilibrium

through the soil solution. There is a very lose relation between the

soil oolloids and plant colloids. As soon as the plant consaues water

and ions needed for its metabolism this equilibrium is broken and then

it is immediately reestablished. The relation between the soil and

plant oolloids and the soil solution is regulated by the phenomon of

Donnan equilibrium* It is well known that the plant absorbs its mineral

nutrients in the form of ions in solution.

The plant obtains its water and minerals when its osmotio pres-

aure is higher than that of the soil* Sinee the osmotio pressure is pro-

portional to the oonoentration of the solution, the osmotic pressure of

the soil solution increases as the mount of soil water diminishes. If

the amount of soil water continues to doorease a point is reached in

whioh the soil solution possesses a higher osmotie pressure than the

plant* At this point the plant begins to supply water to the soil* The

point of approximately equal osmotio pressure of plant and soil where the

plant begins to lose water is called the wilting point*

Jeazr (17) proposed a theory to explain the absorption of

nutrients by plants in soils with the moisture content below the wilt.

ing point, exrlainint the absorption as a function o' eleotrostatic forces

established between the oolloidal particles and ions, but this theory

has not yet been accepted.

It is also necessary to keep in mind the active and intense

action of the microbial population of the soil which causes an ever

shifting of the equilibrium and completes the dynamics of the soil*

The purpose of the work reported in this paper we to deter-

nine so=m of the physical and chemical characteristics of certain agri-

culturally important Florida soils.


A vast amount of material has accumulated concerning the acti-

vity of soils directly attributed to the colloidal particles but vpaeo

will permit citation of only those works which are essentially related

to this investigation

Ensainger and Gieseking (11) studyinP absorption by montmo-

rillonitie clays found that proteins did not reduce the tose exchange

capacity of olays ianan alkaline medium. However, the hydrogen ion

concentration was increased, the bass exchange capacity decreased. The

faot that an increase in the hydrogen ion concentration increased the

basio properties of proteAna would indicate that they are absorbed as


Peeoh (t2) analyzing soils from Florida groves verifyed that

the or anie matter constitutes the main source of colloidel material

in may Florida soils because of the mall amount of clay present, and

consequently the inorranio soil oolloids contributed very little to

the exolange oapaoity*

On the other hand, satteon (22) in a stidy concerning the

form and functions of water concluded that the soil colloids imbibe

greatly varying quantities of water depending upon.

(1) Their composition or 7ore directly upon their exchange


(2) The nature of the exohangeable nations,

(8) The charge of the partioles,

(4) The position of their isoeleotric point if amphoterio, or

(6) Their ultimate ph, i.e., the strength of their aiod groups,

(6) The ooncertration of free elootrolytes and the valenee of

the ions, both according to the Donnan Bquilibriurm

Anderson and Mattsen (4) studying the properties of the oolloidal

soil material stated that the correspondence between pH ad total quantity

of exchangeable bases is probably due to the faot that those oolloids,

which under natural conditions, contain the smaller quantities of total

exohanreable nations usually contain ezohanpeable hydrorens ions (or iron

and aluimnum), while the colloids with the higher content of exchangeable

nations are usually saturated with the monovalent and divalent bases.

Briggs and 8ohants (7) studying the wilting oofficient of dif-

ferent plants and its indirect determination found a linear relationship

between moisture equivalent and wilting ooefficient and hygrosoopioe soef

ftolent and wilting coefficient which is independent of the texture of

soil. They proposed the following fosrulase

Wilting ooeffiioent equals moisture equivalent
T1.8 4 06.301

Wilting coefficient equals hygroscopic ooefficient

They analysed a Treat number of soils with a large variation in content

of olay* On the sams soil and using the seas procedure they verified

the following relationship between moisture equivalent and meobanioal


Moisture equivalent equals 0.08 cnds 4 0*22 silt 4 1*05 olay.

Baver (6) stated that numerous investirations sinoe the original

work of Erig a and Sohants. hae shown that this factor for wilting coeffi-

sient cannot be used :or all soils. Bowsver, Veihmayer and Hendrickson

have confirmed the ori- final contention of Briggs and Solants that all

plants reduce the moisture of a riven so 1 to about the sam value before

wilting ooours. The tension of the soil water when permanent wilting

occurs is at pP of about 4e.8

Smith (28) in his paper on the relation of the mechanical an-

alysis to the moisture equivalent of soils stated that the meehanioal

analysis depends only on the amount of the various sised particles in a

given soil, whereas the moisture equivalent as determined by ears of

the centrifuge rives a soil constant which is influenced not only by

the sise and amount of the different particles present in a soil but

also by the shape of the soil partioles, the amount of organic matter

present, the amount of soil collide present, and the ohemical oomposit

ion of the soil. Be concluded that it will be necessary to make

an actual moisture equivalent determination for satisfactory results*

Alway and Russel (1) analysed about 80 virgin prairie# soils

and obtained a good results usinr the moisture equivalent formula of

Briers and Schant*s They stated that the effect of considerable quanti-

ties of organic matter is, in general, to five the ratio of the moisture

equivalent to the hygroscopic coefficient a hither value, and proposed

the following formulas

1. ~rgroscopio coefficient equals wlltin coefficient x 0.068

to ItCroscopio coefficient equals moisture equivalent x 0*37

3. HErrosooric coefficiert equals 0.005 coarse fraction f 0*07
very fine sand f 0.82 silt f 0*89 clay.

Lipman and Wayniok (21) studying the effects of climate on

important properties of soils used the moisture equivalent formula of

Brigcs and Sohants, but did not obtain good results.

Camargo and Vageler (9) working in tropical soils used a for-

aula to calculate the inactive water (Wi) based on hygroscopio ooeffi-

oient (Sy) and the osmotio pressure of the roots of plants (D)
Wi equals 6 5 vol%

They found that in soils of Sia Paulo, Brasil the oasotic pressure is

about 6.25 atmosrheres, correaponding to 2ty. i.e., twie the Byrros-

copei coefficient* Every physical analysis ooncernin- the water in soil

was based on hyrrosoorio coefficient determined aooordinr the procedure

of ltaeoherlioh and usinr Vreoler's formula y aT to calculate

the aimann of water adsorbed (T) during the time (x), being (q) the

modulus of the equation
S Amral (t) made a statistical study of Tageler's formula, using

uheav olqy soil et PrstM and oelsulated the yrosoorle ooefisient *o
eordina to t~telr's method of xtrapolation and see to the fellowlat
tI It iI necessary to expos the *oil to a hydrie st o phw
at least ton days
to tenty days ~xcyuro ot the soil seeordilr to Uteoherliob
Cave go d rodslts
So Ite ae-aler mthod of extrapolation, weithine the soils
a the eoonad sad fourth days o exposure and changing the
solution after wichinc Cwe pood resulted

But the stattitical analysis of th eq .*tioe la c~ue3tion did tot show
eilniftiot t eorrelatimee n thebr paper it. u verified that dryiag
the soil before the determinatioB of the gnrroseopio ooeffioient gr
low resltse This probably besuse heat foleeulttes the or~eaie soll

tmnpuir (80) demlopod the theory of adsorrtion and e tab

listed the equation I : used by GOtf eand Diels (1t)* Ltea
muir stated that ia the oondesatlo of a vwper the solliseos are
Wholly Iteletios *so that ewr -oleule striking the Ourteee eodesee
Oetms ead Daniels (U) ntprint etTr say there ti a *ntinum r flight
of uolecule from the etebt n phase to the earfhe in the opposite direet-
its tnh rate at whioh moleculee are edsorted dfeends aR there ftetoreg
via** (1) the nmt r (a) striktin the surface per second (whih oan be
oselulated frt the kinetto theory of Ceos), (t) the fraction (a) of
Utaidet olecules hbish adhere end (8) the are (lo) Whieh' is not
steered by asserbe mle uloe (c) bnbac thbe treaite owraed, sr (r)
t the rate of emprumtion .ro a .0o1ptely omrod sourte*
bre abbtla d roites (35) se d the Tacetlers tfer e sad

wthted f extrepplate to determine the Ipgeoptis osetieeat la

soils of Brasil and obtained satisfactory.results

Anderson and Byers (3) studying the character of oolloidal

materials in certain soils found t)at the podsol oolloids of the B hori-

sons contain monovalent and divalent bases somewhat in excess of those

of lateritio colloids of similar horizons (major constituents)* Further-

more, the podsol oolloids of the A horizon with major constituents *sii-

lar to those of the pedocal have somewhat similar base contents but wre

oharaoterised by property values much lower than those of oolloids from

the more arid regions. This is probably to be accounted for by the

presence of free silica in the coll"id. They found much wider variations

in the adsorption of water vapor over S8% H2S04 than the values shoa

for the oolloide of ,ost aprioultural soils.

Holmes and Edginton (16) studying the variation of colloidal

material in certain soils suoh as Miami, Chester and Colil series con-

eluded that the colloids of a given soil series are remarkably oonstat

and essentially different from those of even closely related series.

They presented data which shows olecrly the general similarity of the

different profiles of a single series and a -arked variation between

the differen-. series. The extent of variation which ocurs within a

single horisoa was not clearly indicated*

Anderson and Ihttson (4) studying properties of the colloidal

aoil material concluded that a relationship bet-wen properties is in-

dioated by the fact that variations of the oolloids property

usually parallel variations in other properties. The correlation be-

tween variations in the properties studied might be explained on the

ground that these properties are dependent on a few more fundamental

properties, sueh as chemical nature, alse, sad structure of particles,

and that these more fundamental properties are related*

Brown and Byers(8) in their paper on properties of lew lag

land and Piedmont soils concluded that the hyrroscorioity of the oolleide

of the eight soils showed considerable variation within the profiles, but

tiere was also a certain regularity in their variation.

Wright (29) in his book on Boil Analysis states that hygros-

copioity gives a rough indication of tV.e oollidal content of the soil,

but results obtained at different times are not comparable, owing to

the ohanges in the humidity of the atmosphere.


Three soils closely rdrted genetioally were selected for

this study. The soils selected were Norfolk fine sandy larm, the Tifton

fine seaty loao and the hMrlboro fine sandy lom. These soils belong to

the Yellow Podsolio Great Soil Oro p and are developed extensively in

Northern Florida. Offtiil profile samples were obtained through the

oourtesy of INr J. Re Benderson of the Soils Department of the Florida

Agricultural Experl-wnt Station. The Tifton fine sandy loam and the

Norfolk fine sandy lona were taken from representative areas of the res-

peotive types in Walton County, Florida, the sample of Marlboro fine sandy

loan was taken in Washington County, Florida.

are oharsoterised by Henderson (14) as followed

Tifton fine sandy loa

Brownish gray mellow fine

Yellow heavy friable fine

Yellow heavy friable fine

Yellow heavy friable fine
a great Iany pebbles.

Yellow heavy friable fine
a great aazy pebbles.

Norfolk fine sardy loam








clay loan with

sandy clay loan with

Gray loose fine sandy loam

Yellow gray loose fine sandy loam grading to gray

Yellow mellow fine sandy loam with a tinge of gray.

Yellow friable fine sandy loam

Yellow 'riable fine sandy loam

Yellow friable fine steady loam with red and brown

Gray, yellow and red bottled, friable fine sandy clay

Shrlboro fine sndy loea

Dark gray mellow fine sandy lam

Brown gray mellow fine sandy loam

Brown yellow friable fine sandy *lay loan

Brown yellow heavyy friable fine sandy clay

Brown yellow heavy friable fine sandy slay

Brown Yellow red and gray mottled heavy friable fine
sandy olay*

The soils









10" -U


Samples of the A, JS and B horizons of the Tifton fine sandy

loam, the Ar B and C1 horizons of the Norfolk fine sandy loam and the

AL, B and C horizons of the Marlboro fine andy loam were prepared for

analysis* The physical arnalyses made were, mechanical analysis, specific

gravity, volume weight, moisture equivalent and hygrosco-ic coefficient*

The physical constants calculated were, porosity, internal surface, swit-

ing ooefficient and hygroscopicity* The chemical analyses made were,

pH, organic matter content, base excharte capacity and exchangeable

oaloiuna magnesium and potassiume The per cent of base saturation was



The mwhanical analysis was made by the Official (24) pipette

method. The specific cravity was determined by the pionometer method

as modified by Anderson and Matteon (4). The use of methanol instead

of water is advised because the non-polar liquids give more reliable

results than water* The volume weight was determined in the usual

maner* The moisture equivalent was determined by the procedure re-

oommended by Wright (29)* The Eygroscop:e coefficient was measured

by the method of Mitcoherlieh (2) and also by the procedure reoomended

by Robinson (29),

The pH was determined by the glass electrode and the organic

matter content wus determined by the procedure reconmended by Dyal and

Drooodf (10).
The base exchange capacity and exohanpeable bases were deter-

mined by a modification of the neutral menias acetate method (s, 1i,

19, 29). The exzhanreable bases and hydrogen were extracted by leaoh-

ing 200 grams of soil in a Buohner Funnel with 800 al. of neutral normal

ammonium acetate* After washing out the exces asamonium aoetate with

600 oal of 80 per cent alcohol which had been adjusted to pH 7.0, the

absorbed amonium was replaced by lesohing with 600 al. of 10 per cent

sodium chloride. The base exchange capacity was determined by determin-

ing the amnoniu absorbed by the soil in the leaching process

The ameoniua asetate leaohate containirg the exchangeable bases

and hydrogen was evaporated to dryness and the organic matter was des-

troyed by means of hydrogen peroxide. After dehydrating the silica

the residue was disolved in dilute Hoi, filtered, and made up to a

volume of 100 al. Celcium was precipitated as the oxalats in 60 al.

aliquot, filtered and washed with hot water, dissolved in 10 per cent

NH804 and titrated with 0.02 1 b04o Prior to precipitation of calcium

iron and aluminum wre removed with ammonium bydroxide. After the re-

moval of calcium, arnesium was preo ritated as NCR4P0t, filtered ad

washed with 10 per cent amnonium hydroxide. After drying, the precipi-

tate mw dissolved in 0.1 B13804 and the excess asid titrated with

0.1 1 IWaOH using brom oresol green as the indicator.

Twenty five mal aliquots of the original solution were neutral-

ised with NaOB uaing phenophthalein as the Indicator and evaporated on

the hot plate until dry. After oooling t2 ml. of approximately 0.15

I acetie avoid ware added. Amonia was tested in this solution using

Ieesler's reagent* The potassium was precipitated with 6 al. of NCe 0

(10 t) in a sal water athe The solution was left in a eool placs ever

night. The preeipitate was filtered in Goosh orunibles with asbesate

peds exidiaed previously and washed with odl water* The precipitate

was dissolved in 14 V2804 and titrated with 0.0 1 E nbo until the solu-

tion became pink. The excess h04 was titrated with 0.0 1 sodium oxa-



eohanical compositions The results of the mechanical analyses

are presented in table 1 and the mechanical composition is represented

by Fig. 1. The data in the table show t at the soils are properly class-

ified as fine sardy looas. The Al horizon of the Tifton fine sandy loam

contains 29.94 per cent of silt and clay. The Norfolk and Marlboro fine

sandy loams contain 25.69 and 21.94 per cent silt and clay, respectively.

The data also show that the clay content of each soil increases with in-

creasing depth. The B horizon of the Norfolk fine sandy loan is lifhest

in texture, containing. only 8567 per cent olay. The B1 horizon of the

Tiften irne dandy loam certain 26566 per cent delay and the BI horizon

of the Marlboro fire sandy loam contains 53.85 per cent clay. The

mechanical composition corrirms the field identification of these soils

and the data will be coor donated with other physical and ohemioal

Specific gravity The specific gravityy of the soil from the

A horiorne of Tifton and Varlboro fine sandy 1 a!s was lower than that

of B and C horizons of the respective soils and indicates appreciably

wore organic matter in the A horizon the in the lower horizons. There

was very little variation in the speoifie gravity of the different

horizons. There was very little variation in the specific gravity of

the different horisons of the Norfolk fine sandy loaa* indicating a homo-

genous mineral composition The speoifie gravity of the Bh hortoin ot

40 qq 81 44

I; aa row
oq qtS0lJ^SS ( qq
S jars 8. ss4


I 1 0q(3v

- 43 8*0SiSMa 8 8a g

O ***"*a rsa-a g "ass
""1 a

i jis I

a I)q4t

I I.SMqs -








V SILT? ClA 30\


--- / L. --







AM,- Al
Ma- C

- Fip. I -



this soil was lower than that of the Al horizon. The specific gravity

of the By horizon of the Marlboro fine sandy loan was considerably higher

than that of the Bs horizon of the lorfolk fine sandy loam or the Bf

horizon of the Tifton fine sandy loas. This would indicate a higher

iron content of the Marlboro fine sandy loan than that of the other two


Volume weights The volume weight of the soil depends upon

texture, specific gravity, coupotness and the amount and nature of

orranio matter. The volume weight of the different horizons indicate

higher organio matter contents of the A horizons than those of the

lower horizons and an increase in delay content with increasing depth*

The firur-s on volume weight with those on specific gravity serve as a

basis for the calculation of porosity.
Internal surfacso Sinoe many reactions in the soil are sur-

face reactions, a large surface area denotes activity and high catalytic

power of the soil. The mall size of the clay parti lee implies the

development of a large surface area* The internal surface of the hori-

sons of the different soils was oaloulated from the mohanical oomposition

data* The data are presented in colum 7 of table 2 The internal sur-

fase, or surfaoe area developed in a sample of soil equals the area of

each particle multiplied by the number of partioles. If the particles

of a uni onr soil fraction of disaster D are assumed to be spherioal,

the area of the particle is riven by the formula 1e. The number of

particles in a given weight of soil is liven by the formula 1 where

v equal volume of each particle and d equal density. The surface area

of a unit weight of soil, then is riven by the foraulaal! D 6 *
RT re7

0* -v-0 a1:
P4 Ord0 0 0"4



I 1 W5 10 ,
* "




-- Fi.2 --

^ 0



Q 30

The data in the table *how the enormous amount of 765*1 square

meters surface area in 100 Crams of the B2 horizon of the Marlboro fine

sandy loam. The surface area of the different horizons reflect the clay

content of the different soils.

Eygroscopio coefficient Two determinations of hygroscopie

coefficient were made* The one with 10 per sent HE804 according to

the method of Mitacherlioh and the other with 3.3 per cent IS04 aooord-

ing to the method of Robinson* In both methods the soil was placed in

the dessioator under vacuum. The difference in concentration of 4804

represents different osr otio pressures to which the water adsorbed on

the surface of the particles is subjected. The value of this oamoti

pressure in the two oases my be calculated. The osmotio pressure

of a solution is proportional to its concentration and the number of

ions and inversely proportional to the molecular weight of substance in

solution* This relationship if riven by the formulas

p U4 x P x n where

p : osmotic pressure
t224 constant of perfect gases
P a concentration of solution per liter
IM wsiht moleoular
a number of dissooiated ions.

In the oase of 10 per sent tg804 the osmotio pressure p : t2.4 x 100 z I

equals 6656 atmospherese la the ase of 8.3 per sent "l04 the aometie

pressure ps t224 a 55 z I equals 22t. atmospherese
The adsorption of water is a function of several factors inalud-

inf time The two sets of ourvea (Fig. 8 and 4) were obtained by vary-

ing the time the soils were subjected to the different osmotio pressures,

The adsorption of water by the soil in both eases seea to feller the

sams kind of curve. The maximum adsorption was attained oan the 20th day

and in the case of 10 per cent I80 the adsorption was smaller than that

of 3.3 per oent EBS04. According to Vageler (9) and Amaral (8) the equa-

tion of this curve is y z IT where x is the time and q and t are
z 4 qT

Vageler determined the value of T by extrapolation, using the

weight of water adsorbed on the second and fourth days. From the above

equation one obtains

At the 2nd day 1 1 4

At the 4th day 1. 1 4
74 T 7
Solvin this equation for T and q one obtain
Y y 4(y4 yg
T and a (
Y2 4 Y2 YL
Then, knowing the moisture adsorbed on the 2nd day (y2), and at the 4th

day (y4), one can calculate the value of q and T.

Applying the formula (2) the hyrroscopic coefficient was cal-

oulated for eaoh soil and then compared with the value determined by experi-

nnt. The values obtained are given in table 3 and stow that there was

practically no difference in the experimental and calculated values.

It is very interesting to observe that Vageler's equation re-

presents the same urve as that of Lanpmuir (20), although the meaning of

the letters are completely different in the two equations* In other vords

two different phenomena concerning adsorption by the oolloidal particle

are subjeet e the sae mathematical law.

A comparison of the curves obtained by the two methods used

shows that the adsorption of water was the same in both of the oasae (Fig.

- Fi9.

At*. to W. 0R O/NS ON







000- -0 -
c^r^ J^y~,y^.

i4 ie fo to

J.J,70 ),?50

. #,t

-- i. --
Ac. to M/iTrCNERL/CH
/10% 11,54














*"A, ="r
< -1 A
L e.#D

-' -~~b
a a-- 2






Hpso+ 3.j% r

A, As 5, A Bas CI Ai Ba C

F9. 5 -

SOeSO /o0






10 3

A, Ba C, A, BA C

Table So Comparative data showing the difference between the determined
and oaloulated bygrosoopio ooeffiioent sooording to Vageler's equation

8 8
lo. Soil Type Horisonm ia Froscopio ooeffloient a Differen*
a sao. Miteohrlioh a
DsteruLnt 'Glo~UaW

1 Tiftoi fine sandy
lo am .8 t.81 0.03
2 Tifton fire sandy
loa 83.01 t.99 0.08
8 Tifton fine sandy
loan B1 50 5.01 0.09
4 worfolk fine sandy
loan L 1.40 1.8 0.t08
5 Norfolk fine sandy
loan Bt 1.7 106 0.10
6 Norfolk fine sandy
los C1 S830 .O19 0.11
T Marlboro fine 1sndy
lo" L 25.68 2.56 0.08
8 Marlboro fine sandy
loes B 86.0t7 9 0.14
9* Mrlboro fine sandy
e1-s C 6.51 6OT 0014

5 and 6) and the comparison of the adsorption curves with the internal

surfc e shows t':cre .s an sprarent positive correlation (Figs. 8, 5, and

6). Since the or-anio matter in the A horis *ne did not increase the

hyrrosoorcio coefoioient. It may be concluded that the hygrosoorio coeff-

icient is an index of inorganic colloidal particles.

moisture equivalents The moisture equivalent is defined as

the percentage of water retained by a soil when that soil is subjected

to a force 1000 times that of gravity. The moisture equivalent of the

three soils studied was determined and the results obtained are present-

ed in column 8, table 2 and represented as the historram in fieg 7.

According to the histogram and the data on internal surface

and organic content, is appears that moisture equivalent depends

on the combined action of clay and organic matter. The soil of the

surface horisoas, relatively rich in organic matter, possessess a larger

moisture equivalent than the soil of lower horizons. Cn the other head,

the hygroscopic coefficients show that the organic -atter possesses the

ability to hold water the sane as the elay but does not have the same

capacity to absorb water vapor* In othei words, the moisture equivalent

is an index of the ability of soils to retain water, whereas the hygros-

eopic coefficient is an index of the inorganic colloidal content of the

soil, its os oticc force and its ability to adsorb water vapor*

rEVroseopicitys Tygroscopicity is also called hygroscopic

moisture and residual moisture* According to the histogran (Fig, 8)

one observes that the variation of hyrr.scopicity within the soil type

is more affected by the organic matter than is the moisture equivalent*

It my be concluded that the limit of adsorption of water by organize

matter is resehed more quickly than it is by slay* The sand particles

Sj oo j 4 a m a














0 a

I o

H-" *









CdPI Ei #6 -

'6 0 0

W s *J M '

IP M 0 0 4 14 1 0
S.4 r r4 o- 9; o

Ce o< o
0 S

S- 0 0 6 0 0 0

* *
% 0.4


l 0 0

ie QO o

Table 5. Comparative data showing the difference Letween the determined
and calculated moisture equivalent eacordinr to Priggp and

SMoisture equivalent u
No. Soil Type Horison s Deterulne Caloclated Differenee

1. Tifton fine sandy
lo3 n Al 11.75 17 47 5.74
t. Tifton fine sandy
lo5 a As 10.88 31.67 11.01

loau B1 15.2 81. 36 16.13
4. ortoflk fine sandy
loam A,8 11.S6 ST17
6. lorfolk fine sandy
low B 7.41 14.88 7.47
6. lorfolk fine sandy
loss C2 15M 85.09 10.T7
7. arlboro fine sandy
lo 1188A, 14*10 1.77
8o. Mrlboro fine sandy
lotm Bs 16 .7 57.91 21.18
9o M3rlboro fine sandy
lom C t08.10D 9.89 11.19


-Fig. 7--





o to

:~~~~ Li.. "~C


br~fl; *.If a

h ..

6 a

^ .'1
t. i *
'** :a '^ '. < < ^ -
m a' r a f

i *1, *

'^ **


I aq -a t IOWAy *V*a eft St a th soU
das mb q~pt to h fo..kueOod lot" of a aepausyt IL%.e dorSm
tE be i | Ss l t lAu .t.*1 mm r iesL*imaltmetm I**t5 *
Sr tv b .ta *"W "st a"ms" 8 u st
arn F el Wp ".atie Im Ie v 1 oril 0. a 6% As"" *el
UK tss "so (a m wwld of base "%**Uai MgW
*r AseL. is ra l oe st I pw emo aH w wet r eobt saiia so
*feew sts vs "t"am as Mts hqm e el w ($eA. t) a
SreY 4M1tarsess a was fAU wL rter ia Inasalso wmn
tai ww i i. aft %*,A kWlm s4 *4 era" tie9 J.i.
ms 11n UMU a45 bWe 0,I haUls sIa bef *mmwsluo.
new us tt UntIS 4tfsense lat am ese Mslase 41 tM 3abev

vsh bultibasms eIMMA .ia I.usa te. thaeat*nW"u

i-Ise up w 1 4. *M* *.gl se ite ..a
** *** yi* **A *( ** arr NM *M
*w.A i-os ass t rs e e H Itre ta' liI oAl

*u <*w0NSSIa. i l l 4. tS i.
u"r^&^&^I 3 ) e7 .^J j& ^^ Q w c L ^k ^^ i^c If
^^1^% O 9 -4 -B --
m i r a h1E c-
"~ur ~ jL1 IF~Lip







II 1 !!!]

ga e t qq t ae

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hilll allf


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I 6

0 .o io ;w 4. to go io i





A A A A Ba A AS a C
F9/. 10 -

the Tifton fine sandy loem sd the Norfolk fine sandy loe. lvmeir

the suritee soils, due to the orenie hitter oostent, are higher in *

exehangeable bases than the 1-er horisoas within eaeh profiles


Three horizons of thee ohbraetristies Florida soils, namly

the 4 AL ind B horizons of the Tifton firn sandy loans the A B and
C horizons of the Norfolk fine sandy loan and the Jl B3 and C horisas

of the Irlboro fin sandy loa were sleooted for this study. The studies

wre designed to oompareo so of the plhyioe-o*helol oharseteristies

of the three soils and the horizons within each soil type.

The phy eal analyses mde were meb aiol analysis, speoifie

gravity, volun weight and bygroseopie ottffielest The eheial deter-

mination rmde weres pB, organito tter coennt bass exehage oapaeity

and the ezohagesble eeltiam naImsAe ead petassimm With the defta

obtaind th tfelleaing costants were ealeulated per eent pore spea,

internal surface waiting oetofieent as a function of bygromsopi eetfi-

ienta moisture equivalent as a tuaotion of chanieal amlyrsier hgros-

eopie e*effioient by ageler' equation and the percent base sature
ties of tih soils

Th fosllouag relations re established (1) There ms as

larg differemle in the ooffitient elulated as t function aof moist

equivalent ant that ealeited as a function of the bWproseopie meeffi

letn*# (1)$ (3) the aistur equivalenk t aleulaed s a funotioa of

epe ceroffie, ealscute I w* et tissa adrt that dretef as

b 0|upe e- O (4)f (4) bgreseepi **ffsieomt Msthe iste a 'rutma

sad finally (s) the base exhaep apaeity varied directly with the

lay ead rganie aetter contenekt

The rerults obtained in thee rtudies may be eumrised briefly

as fellogw
(1) The Ibrbere fine candy leam contains more lay and has

a higher exohane capacity than the 2t ta fine sandy lom er the Norfalk

fine sandy loem. The Norfolk fins sandy loan contained les** lay sad

rgatie mat r and had a lower exchange oapeaity than either of the other

(8) The surftae horisons of eash soil contained sore erganie

matter than the suburface horisonso the organic mstter content of the

surface horizon of the three soilc my be arrangeA in descending oder

as fellowes The Mbribeor fine andy lom, tifton fine seady loam and

lorfolk fine sady loaem
(5) The surfaeo herisoan in each soil type contained mar ex-

ehangoable ban than the subeurfac horisone.
(4) The bggro eopie ooeffieoienwilting eeoffieientu muicture

equivalent and )ygrosopiity were not oorrelated phenomaea
(6) the h groespie *eefft lent may be considered an index at

the eme ti pre e fr of soils ad is a ftnetiea at the clay outmt of

the cell.
(6) the miatoSequivaet my be omaide ed aa luaex ef tb

pemr to retain mater e a reultant of Ith. embined aetiona f clay ad

(T) The ~grseepieity ift aeil is a fmeti f orgat nic mae e

ed uele, but varies with the irntue eM tempeatew the sir.
(a) the iatorMi euwfam a s il may Nsrvm e ea iles atf its
; rr.

rZ lvity mad is related to the surface phenomena of the *olloidal part-

(9) TVeelor*o equation may be used to elaoulate the h)yros

eopioe oeffielect of the soil, whereas the formula of Brigg and Seheats

is umsatisfeetory for this purpose



oI Always F* Je and Russel, Ji Co Use of the moisture equivalent for
the indirect determination of the hygrosoopio ooefficient*
Jeur. ACgr Roe. 16 8M-846,l 1916.

to Amaral, Edilberto, Irrigaoio e fiuelo do solo. Bo. IXnsp. FPed
0. 0C S,0 Brasil* 148 44-U, 1960

Is Andersea, NM So and Byrsr, Beraoe 0. Chareater of the oelloidal
materials in the profiles of certain major soil groups U. 8.
Do A* Teh* But* t28, 1981*

4. Aaderson, M. S. and Matton, aenue Properties of the oelloidal oil
material. U. 8. D. As BSal 145, 1940s

So Association Official AIricultural Cheuistse Official and tentative
method of analysis. 1940

o BDver, Le Do 8oil Phytsios John Willey & Sonls Inco I. ToY 1940

Te Brigrs* L. Je and Sohants, We L* The wiltint coefficient for dif-
ferent plants and its indirect determination* U. 8. Do A.
Bure Plant. Inde Dbal 280 191l.

8. Bromn, Irvin Ce and Byers, Boraoe 0 Chmieal and Physial proper-
ties of certain soils developed from ranitic materials in Iln
Ibgland sad the Pledamt and of their oolliodse VU. So D A.
%ehe Dule 69, 1988.

o Caergo, Theedureteo ad Veaeler, Paulo Amlise do esloes I Analyse
ply iees Inst Cepe. Bld Teooh. 4, Brasil, 1938

10. Byals R. o aa D redeotf Me Proedures for the determination et
rganie matter in soills Prooo S*ol Soie Seeoo. n* I (in
pers) 1361

It masinger, Lo s. d e6S1Bi g t* J. B. The absorptie of protein
by e lmrtekite elis and its eofeet oa b eze*hange ape-
*i. Sell hi Se 51 I-13i, 1941.

Ie geotm Po N oRe and Damiel# o Outline etof theoretical *hemistry,
Jote Willey & Some, lno. i To., 1981

1U Na*, 1s O The velaumtrie determinati eto mfanessi Joure Ar.e
*ee* 88e 1*We, 190.0

4* Badersee, i Ro the s A *of Flerida. Fleo Agro Up* ta** ld. M8,

Ul 11Ubreo, We 4. MA d ideit Go Be Fe A plied Imagerao Amlyssrr
aM" Wllley & Soes, aBoe e Te* 19M.

16* Blms,1 IRe So ad diangton, 0o Variations of the solloidel amterial
extreoted from the soils of the mei, Chester and Colil series.
U. 8* Do A. Teeho Butl* 29, 19300

17 Je o H and Overstreet, 1 Cation interehane between plant roots
and soil oelloidsr Soil SiGi 4T, tt57 199O

18. KIrr, H. W. The identification and composition of the soil alumino*
ilicate sotive in bass exxohao and soil saidity. Soil l.e
8ls 8586-98, 1988I

19o. olthoff, oI M. and Sandell, Be Teatbook of Quantittive I2-
orguane Anlysiso The Nre illan C0o No To& 1936e

300 LaungMi Irving !b oonatittib sand fndeintel properties of
solids and liquids Joewo JAnr Chase Soc. 8e0 226T, 1916*

Stl Lipman 0. Be ad tayniek, Do Do A detalod study of offeots of
*llmte on important properties of soils. Soil Sio. ls -4.I

St. Mbttha, ante The law of soil olloidal behavior V Fo rms
and functions of matfo Soil Sa*. 3o 5018882t 19.*

35 Ibhre Wilhela ard Jobia, leavieon ard GOm do Preitas, Seper
Ibpe odaefloieo* dae Btaeeo xpo Fit* da Prontetra. Separa
do Anne1S do I OCaresse Rlioradense do Agraem ia 1941e

486 Olatead, L BD, Mad AlesaAder Le To, ad tAddletom,. Io Pipette
noted of eehanieal analysis f soils based oa improved dtis
persioa procedure V. S. Do A* T~eh. Bul. 1SO, 1980

3S. Iwooh, M ihel bendeal studies ea soils trea Floride eitrus gror
n1ee Agro Usp. St Tekh 3lo 9540, 195.

M lRobainema, Fo Wo 8iles their wor iJ ostitutiom and oleasifieotion
hoI m Arby & CG, l odm, 1Lm

2To Robinson, Wo 0o btheds and preoodure o soil analysis used Ia the
Division of Soil Cheistry mad Physloso U 8. Do. A. iroe 189,

o nAit, hs Alfred Relation of the mohaneal analysis to the moisture
equivalent of soils. Soil 8So 4* 47t2 191.

a WlightMs 0 Se ol analysis, Ptqlol ad Choeaoal mthode. Thmse
Mbary & ILades 19.* -

Msoyr Pavagsea us bra in I1 e Jansiro Drasil, Dsoer
U. 190We b me grasMat ftn to 1bs9a 8aporw d4o Agriulrtun do
It.ade dto maUs Grni, Vlq* steAb mo Niesms Owcts,%rtssU with
s terw Lagemnirb APrem# knMDosr 19T. Fm JAIsstuy 1n bo
sra4 as sustrnw a Isw ts kpar oat Arlmlthhuw asmisabwr at
tas enlsp, aa m protlad toAu hAUt Proeftor th fo ~ ins
ywar il&h posietU he aw holds. In AacIo, 104 he ms aunto a
seatorship ar the aiwesi of nrid i"throb tb Zntr-AMrUaM
latitae for tow -to* yarw 19-45. NI eqets to obtain te s.
gn of Master of Soiaio an Agrioultro n MJay ot 195.

This thesis was prepared under the direction of the Ohairmn
of the Cadidate's Supervisory Omitte. and ha been approved by all
members of the Comittee* It was submitted to the Graduate Counoil ad
was approved as partial fulfillment of the requirements for the degr
of Ueater of Soienoe in Agrioultuwe.



,i m,
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