• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Introduction
 The land and its care
 General principles
 Sources and functions of fertilizer...
 Home mixing
 Fertilizer formulas
 The meaning of pH
 Composting and mulching
 Soil pests
 Soil organisms -- what they are...
 Citrus fertilizer programs
 Composition of Florida-grown...
 Soils and syrup
 Fertilizer consumption
 Florida soils
 Uses of lime














Group Title: Bulletin
Title: Soils and fertilizers
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00003035/00001
 Material Information
Title: Soils and fertilizers
Series Title: Bulletin
Physical Description: viii, 157 p. : ; 22 cm.
Language: English
Creator: Brooks, T. J ( Thomas Joseph ), b. 1870
Florida -- Dept. of Agriculture
Publisher: State of Florida, Dept. of Agriculture
Place of Publication: Tallahassee Fla
Publication Date: 1950
Edition: Rev.
 Subjects
Subject: Soils -- Florida   ( lcsh )
Fertilizers -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by T.J. Brooks.
General Note: "July, 1950."
 Record Information
Bibliographic ID: UF00003035
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA3476
ltuf - AMT0571
oclc - 44450263
alephbibnum - 002564293
 Related Items
Other version: Alternate version (PALMM)
PALMM Version

Table of Contents
    Front Cover
        Front Cover
    Table of Contents
        Table of Contents
    Introduction
        Page v
        Page vi
        Page vii
        Page viii
    The land and its care
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
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        Page 41
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        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
    General principles
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
    Sources and functions of fertilizer elements
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
    Home mixing
        Page 67
        Page 68
    Fertilizer formulas
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
    The meaning of pH
        Page 82
        Page 83
        Page 84
    Composting and mulching
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
    Soil pests
        Page 90
        Page 91
    Soil organisms -- what they are and what they do
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
    Citrus fertilizer programs
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
    Composition of Florida-grown vegetables
        Page 106
        Page 107
    Soils and syrup
        Page 108
    Fertilizer consumption
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
        Page 116
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        Page 120
        Page 121
        Page 122
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        Page 125
        Page 126
    Florida soils
        soils
        soils
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
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        Page 150
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    Uses of lime
        Page 152
        Page 153
        Page 154
        Page 155
        Page 156
        Page 157
Full Text
New Series July, 1950 Number 3


SOILS


AND


FERTILIZERS
(Revised)



By T. J. BROOKS
Assistant Commtssioner of Agrculture


STATE OF FLORIDA
Department of Agriculture
NATHAN MAYO, Commissioner
Tallahassee





CONTENTS
CHAPTER

Introduction-The Agronomic Revolution .............
I -The Land and Its Care

IT G general Principles ............................................... ........

III Sources and Functions of Fertilizel Elements....

IV -Home Mixing
V -Fertilizer Formulas

VI The Meaning of pH

VII Composting and Mulching .
VITTI Soil Pests

IX Soil Organisms....
X Citrus Fertilizer Programs ........

XI -Composition of Florida-Grown Vegetables
XI -Soils and Syrup

XIII-Fertilizer Consumption ...........
XIV-Florida Soils ......
XV -Uses of Lime ...





INTRODUCTION
THE AGRONOMIC REVOLUTION

BY T. J. BROOKS
Assistant Commissioner of .Ig itldture

The first agronomie revolution commenced in 1840 when
Von Liebig of Germany discovered the mineral process of
feeding plants. This was the beginning of the manufacturing
of commercial fertilizers.
Nott, tlhat a Imlwl diattiu Ih bliiin ilidEi. 1 W 1 1ev(lltiO
is in the making. This new knowledge is to lhe effect that it is
not wholly a question as to the quantity of products that the
soil yields but the quality, as measured hi aniimal needs. in
foods.
Thl Malthulian theory that the tendency is for population
to increase faster than the means of support has been largely
discredited by the improved methods of agriculture and the use
of fertilizer has done much to increase the yield. The next step
is to improve the quality of our foods.
Countries where radical improvements in agriculture have
not been made are over-populated- like India. China. and other
countries with less aereage.
Life expectancy has doubled in the I;nitedI States during this
generation. There is room for it still heing extended with due
consideration as to the proper treatment of our oils.
Malnutrition is prevalent all over the world-worse in some
countries than in others. Many diseases are known to be caused
by lack of proper nourishment. Other diseases affect illness
because of a weakness that renders the victim unable to resist
pathogenic germs.
Particular soils are required for certain crops. In fertilizing
this same faet needs to be taken into consideration. When a
soil is being "made" adaptability should be considered. Some
soils need ingredients that are not listed as fertilizer elements
in any mixed fertilizer.
As instances we have muck lands in the Everglades where
cattle used to die in grass knee high. They would be so weak
that when they went to a canal to drink they would fall in and





drown. Ordinary fertilizer did not correct the condition but by
experiment it wa. found that copper &ulphate and cobalt would
change the grass to a palatable and nutritious food and cattle
would thrive and fatten. Another type of soil is around Home-
stead, southwest of Miami This is a splendid soil for Irish
potatoes provided manganese is added. No amount of regular
fertilizer would make a ileld but with manganese fine yields
result and of good quality.
These elements act as catalytic agents on the soils and render
the soil elements available which otherwise were not. Most
Florida soils are acid and therefore lovers and bluegrass do
no good unless lime is added to neutralize the acidity. Why are
the honeydew melons of Rocky Ford, Colorado, better than the
same kind grown in Florida? Because of the soil. The pH of
the Rocky Ford soil is 71/ to 8. Soils need "doctoring" to
bring them up to requirements.
Malnutrition is prevalent all over the world. Lack of food is
not the main trouble but a lack of the proper quality, which in
turn is lack of the necessary elements in the soil to produce
nutritious foods.
Shallow cultivation leaves the top soil to erode from rains
and to blow away in dust storms. Plowing deep is best when
done with a subsoil plow This leaves the top soil where it should
be and it absorbs the moisture and loosens the subsoil for the
penetration of the roots of the plants. Cultivated humus is the
only way to get organic matter in the millions of acres where
it is impossible to reach with compost.
Quality food makes for quality health and quality health
makes for quality living.

How to Know What You ore Eating
Now a little more about this quality food problem. We have
learned that the human body requires minerals of various kinds
which it must get from foods if at all The number is somewhere
in the teens. The idea that we need minerals may sound vague
to the average person. But please take note that we eat minerals,
drink minerals and breathe minerals. There are only three
kingdoms in mundane nature: Minerals, Plants and Animals.
We eat all three but we get minerals in our food provided they
are in the soils from which the plants grew. If what we need are
not in the soil, they will not be in the food, if not in the food





so not in the blood, if not in the blood not in the cells of the
body that live on them This means poor soil, poor foods, poor
blood, poor body, poor health. Water is mineral. Air is mineral.
Minerals can be either solids or in gaseous form. Nitrogen can
be "fixed" and brought from the air to a solid form and used
as fertilizer. Carbon is in the air and also in the earth.
Many so-called degenerative diseases are caused by malnu-
trition. Proper nutrition is known to be the remedy for rickets,
pellagra and other deficiency diseases.
Are not these deductions just common sense? Therefore,
what ?
Every person is provided with a canal, the inside of which
is provided with absorbent ducts called villi, that extract the
nutritive elements from the food and pour them into the blood-
stream. The blood carries these elements to the millions of cells
in the body. Different parts of the body demand different
elements which can be had only if the bloodstream has them:
The bones need different minerals from fats, the nerves dif-
ferent from the glands, the all different from the brains, etc.
Now if the materials needed are not to be had at any one
point, what happens? It is "passed up" and the bloodstream
flows on. What becomes of a cell if it is continually passed up?
It starves! Suppose it happens that the deficient element applies
to the cells of the brain! Well, why are there so many in hospitals
with mental disorders Ill health can cause worries, troubles,
anxieties, despondency, forebodings and ailments galore. When
we get old and begin to "slip" it might be lack of brain cell
nourishment. Heart trouble' Yes, we speak of a person having
a "Heart Attack" ehl A heart does not attack It succumbs to
overwork because it is weak and cannot stand the strain that it
could if properly nourished. Food that produces muscle is
needed. The heart is a faithful muscle. It works whether we
are awake or asleep. If it stops to rest-goodbye
People may eat plenty of good food, well cooked and still
starve-literally starve, and never know it. So much greater
variety of food elements are needed than is obtainable by regular
channels. The fifth biggest business in the United States is
canning foods. Most of the materials canned are contracted for
by the canners before they are planted. Some day a far-seeing
canner will see his opportunity and have it in his contracts
that the grower must mineralize his soils as per directions and







require at least a dozen minerals in certain proportions for each
crop-according to the soil's original content.
When these crops are canned a label will be placed on each
container with the guarantee that "THE' CONTENTS OF THIS
PACKAGE WERE GROWN ON SOILS WITH THE FOL-
LOWING MINERALS"-followed by a list of the minerals.
Believe it or not the housewife and the restaurant man will
fall for this and try it at any reasonable cost. Other canners
will be forced to do likewise. The result will be better health
for the country and longer life.
There is more interest being taken in these problems than
ever before. I find the greatest demand for bulletins on these
subjects comes from educators, dietitians, physicians and experi-
ment station operators and journalists.







CHAPTER I


The Land . and Its Care

(From a publication of the American Plant
Food Council, Inc.)

The Earth is a sphere 8,000 miles in diameter, 25,000 miles
in circumference with a surface of approximately 200,000,000
square miles of which about one-third is land and two-thirds
water.

A relatively thin layer of topsoil, which covers the land at an
average plow depth of about seven inches, is the chief support
of life. The world's annual production of food and fiber products
comes largely from this soil layer. Less than half of the earth's
soils is suitable for crop production.

The soil that supports life is created by the forces of nature-
the action of the sun, atmosphere and water along with plant
and animal life, on the materials that comprise the earth. Soil
is a residue of weathered rocks, minerals and decaying organic
matter. It supplies mechanical support for vegetation and raw
materials for plant foods.
Many, many years are required by nature to produce a single
inch of topsoil. Yet, all of this good work of nature may be
destroyed by man in a relatively few years by careless land
management.
Our soil is the foundation of our happiness, prosperity and
progress. Deeply rooted in the earth are our independence, our
safety and the welfare of our people.
America owes her position as a great nation to her soil and
its produce. The power, wealth and vigor of our people are di-
rectly due to the marvelous productivity of our land.
We fought and won two great wars within 30 years and our
victories were due, to a large extent, to the food and fiber pro-
duced on our farms. During World War II, despite shortages
of labor, equipment and supplies, on our farm lands were grown
the record-breaking food and fiber crops necessary to meet the
demands of our 140,000,000 people and millions in other
countries.





SOILS AND FERTILIZERS


Today American farmers are faced with the task of not only
feeding adequately an ever increasing population at home, but
furnishing large quantities of food for other nations. Our con-
tinued world leadership and influence will depend largely upon
the stewardship of our soil.
With wise management, our land can be kept productive to
meet the growing needs of our people. There are areas of land
in this country which have been cultivated continuously for
nearly 300 years that are still as good or better than ever before.

Most unproductive soil can be made useful by intelligent man-
agement. Whether we own land or not, we are dependent upon
the products of the soil for the necessities of life and each of us
has a vital concern in maintaining its productivity.

Since our land is our greatest and most valuable resource, it is
well to consider how much we have. The land resources of the
United States total 1,905,000,000 acres of which about 403,000,000
acres are used as cropland and approximately 1,052,000,000
acres for pasture and grazing. The remainder is used for cities,
roads, homes, parks, reservations, forests and mines or is waste
land.

We have about 1,455,000,000 acres on which to raise all our
food and fiber and to support our animal population. This means
that for every man, woman and child in the United States there
are about 3 acres of cropland and slightly over 7 acres of grazing
land or a total of about 10 acres for each person. As our popula-
tion increases, the acreage per capital naturally will decrease.

When we compare our land resources with those of other
countries, we can better appreciate our good fortune. The United
Kingdom has about 0.38 acres of arable land per capital; France,
117, Italy 0 83, Denmark 161, Belgium 0.29, Argentina 40,
India 0.73, China 0.50 and Japan 0.21.

Soil Classifications
We have many kinds of soils due to various factors such as
parent material, climatic conditions, vegetation, topography and
age of the land. Each soil has a life history which can be com-
pared to the periods of human life-youth, maturity, and old
age-with changes continuously taking place.





TIE LAND AND ITS CARE


Our soils have been relasfied nio ,at ,loil group T}hse
great soil itcups iar divided into soil seiCes; the series into
soil types ani the e in ulun are further subdivided into soil
phases.
Soil surveys of more than half of our farm land have been
made by the Division of Soil Survey, USDA, in cooperation
with State agricultural experiment stations. In recent years, the
Soil Conservation Service has mapped millions of acres. Soil
maps, showing the types of soil and productivity ratings along
with other features, will prove helpful to individual farmers in
learning more about their particular soils and in planning a
sound land management program.
Much has been learned concerning the physical, chemical and
biological properties of soils and a great deal of this information
is available for practical farm use.
State agricultural colleges, county agents, soil conservation
district supervisors or vocational teachers will know if a soil
survey has been made for any particular area and will assist in
obtaining and explaining maps
If a hole is dug in almost any soil, a series of horizontal soil
layers of varying thickness will be observed. Such layers are
very noticeable in new highway or railroad cuts. The soil layers
or horizons differ from one another more or less sharply in
such properties as color, texture, structure and other physical
and chemical characteristics.
A soil profile usually consists of three major divisions, desig-
nated as A, B and C horizons The A horizon includes the upper
part of the profile in which life is most active. This horizon,
which commonly includes the plowed layer, is the most produc-
tive due to its normally higher organic matter content and
crumbly condition. The B horizon is generally called the sub-
soil and the C horizon is the unweathered parent material.

Good Soils-Good Living
Good land is the most important factor in promoting a sound
agricultural economy.

Good soil, good farms and good living naturally follow each
other. This is well illustrated by two near-by counties in a middle







4 SOILS AND FERTILIZERS


western state, designated as A and B. In county A, the fertile
prairie soils are predominately brown and black silt and clay
loams. In near-by County B, the soils generally are poor gray
and yellowish gray silt loams. County A soils contain about twice
as much organic matter and plant food as the soils of County B.
Some of the differences in the agricultural and economic welfare
of these counties, as shown by a state soil survey and the 1939
census, are listed below:


COUNTY A COUNTY B
High Fertility Low Fertility
Average Value of Farm $24,077.00 $4,043.00
Average Value of Land Per
Acre $131.00 $34.00
Average Size of Farms 183.7 acres 120 acres
Value of Farm Products
Sold and Used at Home $3,531.73 $965.79
Crop Yields Per Acre
Corn 54 bu. 34 bu.
Oats 31 bu. 18 bu.
Soybeans 28 bu. 12 bu.
Adults attended High School 23.42% 7.80%
Adults attended College 6.39% 3.73%
Source: National Planning Association Report No. 42

The differences in soils are reflected not only in farm income,
but also in living conditions arid almost every other aspect of
community life. Rich, fertile lands support a healthier and more
prosperous population than poor lands.
Although natural soil fertility influences agricultural welfare,
man has developed methods for improving the productivity of
the soil. The acreage in cropland has changed relatively little
from year to year since 1919 but production per acre has in-
creased rapidly in the last few years. Today, we are no longer
entirely dependent on the natural fertility of the land.
Both human beings and animals draw on the same basic food
products of the soil.
Animals depend upon plants which in turn are dependent
upon the soil. Man not only utilizes plants directly in nutrition,
but indirectly in the form of animal products such as milk,
meat and eggs. The inter-relationship of soil, atmosphere, plants,
temperature, animals and men, has been lermel "The Wheel of
Life."







THE LAND . AND ITS CARE


Scientists have found that the health of humans and animals
is directly affected by the presence or absence of minerals in the
soils. Phosphorous and calcium deficiencies retard animal growth
and body development and also affect normal reproduction.
These abnormalities can be prevented or cured by increasing the
mineral content of pastures and hay fields through fertilization
or by supplementing foods and animal feeds with such minerals.
Prior to the discovery of cobalt as an essential factor in animal
nutrition, many grazing animals wasted away and died from
unknown causes each year in certain areas of the world. Now
such losses are being prevented by an application of as little
as 28 ounces of cobalt salt per acre or by supplemental feeding
of this mineral.
A deficiency of iodine in the soil is associated with the preva-
lence of goiter. Also, certain soils in America are low in iron,
causing a high incidence of anemia which can be corrected by
the addition of this element as a supplement to the diet.
Much is yet to be learned about the effect of these and other
vital minerals on the health of human beings and animals.

Land Management
Good farm land management consists of organizing and using
all of the land on the farm in accordance with sound conserva-
tion principles so as to yield the maximum continuous profit.
All of the land is included because non-tillable woodlands and
pastures, when properly managed, produce income and provide
watersheds and drainage controls.
Only in recent years have farmers generally begun putting
into practice measures for keeping their lands at a high level
of productivity. In the past, an abundance of fertile land in the
United States encouraged some men to mine the fertility from
the soil, and after its exhaustion to move on to new lands. Now
we are faced with the problem of reclaiming this poorly man-
aged land and iin--i it back to profitable production levels.
The following practices are important in good land manage-
ment programs:
Erosion control.
Organic matter replenishment.
Crop rotation.





SOILS AND FERTILIZERS


Acidity or alkalinity (pH) adjustment.
Plant food additions.
Proper land use.
Water conservation.
Drainage.
Tillage.
Soil productivity can be maintained by recognizing the im-
portance of these practices and properly adapting them to the
particular needs of each farm.

Soil Erosion
Before our land was put to plow, the average depth of topsoil
was about 9 inches. Now it averages only about 5 inches-nearly
half gone because of improper land management.
Nature protects the land by covering it with vegetation, such
as grasses and trees, so that when the rain falls it is held back
and soaks into the soil. Vegetation also cushions and breaks the
impact of rain drops.
Man has destroyed nature's protective covering by cutting
down forests and plowing up the land, exposing it to the full
forces of water and wind. After every rain the water rushes off
the sloping land, carrying with it precious topsoil and plant food.
The longer this continues, the worse it becomes and often serious
gullying develops.
Sheet erosion is the more or less even removal of soil in thin
layers over an entire area of land. Although it is the least con-
spicuous form of erosion and most likely to occur without being
detected sheet erosion takes the best part of the topsoil.
Wind erosion also is serious in many localities. In some parts
of the country it is more damaging than water erosion.
The U. S. Soil Conservation Service classifies erosion losses
as follows:
Severely eroded ................................. 282,218263 acres
Moderately eroded ..... ............ .. ......... 775,678,031 acres
Slightly eroded . ......................... 700,512,011 acres
Although soil erosion continues to be a serious national prob-
lem, substantial progress is being made to cheek and repair its
.damage.





THE LAND .AND ITS CARE


In 1935 Congress passed the "Soil Conservation Act" and
directed the Secretary of Agriculture to conduct research to
determine the extent of erosion damage, develop methods for its
control and to aid farmers in developing practices to conserve
our soil. The Soil Conservation Service administers a national
program of soil and water conservation and sound land use, in-
cluding drainage, irrigation, water utilization, land purchase
and sale and flood control. It also directs the coordination of
these functions and operations with those of cooperating agencies
and groups such as the state agricultural experiment stations,
extension service, vocational teachers and individual farmers.
Already much progress has been made and on many farms soil
erosion has been effectively checked with marked benefits to
individual farmers and the entire community. At the beginning
of 1948, 1,026,000,000 acres of 4,303,000 farms were included
in soil conservation districts.
Prevention of erosion should be emphasized since experience
has shown that the restoration of severely eroded areas usually
is a long and costly process.

Some Practices in Erosion and Water Control

Cover, Green Manure and Sod Crops-The land is protected
and soil structure is improved by building up the organic matter
content of the soil through the use of good cropping systems.
Strip Cropping-Alternating strips of close-growing erops
with cultivated crops.
Range and Pasture Improvement-Growing of better pastures
by fertilization, liming, drainage, irrigation, controlled grazing,
reseeding, mowing and other practices.
Tree Planting-Trees effectively check wind and water erosion.
Farm Drainage--Ditches and tile drains remove excess water
and make wet land productive.
Contour Planting and Cultivation-Planting and cultivating
on the contour conserves soil and water.
Stubble Mulch Farming-Allowing plant residues and soil im-
proving crops to lie on the surface of the soil instead of turning
them under.





b SOILS- AND FERTILIZER

Terracing-A ridge of soil is built on the contour across slop-
ing fields to control the flow of water.
Farm Ponds--Farm ponds cheek run-off of water, provide
water for livestock and aid in maintaiinig wild-life.
lWater Disposal Otutles-Protective channels which carry off
excess water from terraces anld colntour crop rows.

Fertilizer in Erosion and Water Control
and Soil Improvement

The use of fertilizer L i important in both erosion control and
soil improvement. Fertilizer provides effective means of con-
trolling soil erosion i twIo wais.
By promoting rapil and iheavior growlli of grass, cover
crops and other vegetation. 'hlis is one of the most effective
ways to bind the spil. cheek .wai-r run-off and increase water-
holding capacity. The dense veg tation and larger supply of
crop residues resilti g fromn adequate fertltiization help to
imrliove soil sirniclllo nd develop ia more absorptive sur-
face soil.
By increasing t-rop )ichll io lesI erodible land. This re-
duces the need for grow ing eculli i ted crops on Iland subject
to severe erosion. Sucl hind lan then lie useil for pernonent
grass and crops whliebi cheek erosion.

LManL) soils altad? iare to I low in plant food supplies for
profitable crop prodnltion. Erosin nolW Is controlled better than
ever hberore but ionltiiois to deplete plint rood supplies. Plant
food losses from (roppnll i,,ld lea(cling ils well as from erosion.
are continuoll ;and reiire constant atlpntion
Commercial fertilizer helps make up plant food lsses and is
,one of the most effective means of improving soils of low natural
fertility. This statement is supported by the National Planning
Association in its publication "Fertilizers in the Postwar Eeon-
.omy From this report this significant statement is taken:
"Even on soils of low natural fertility thie use of fertilizers
and otihr good ainllsagement practices nmake possible a suleoessful
agriculture, especially where the area is suited to high-value
.crops that can pay for rather liberal application of fertilizers ...





THE LAND . AND ITS CARE 9

"It should be noted that under some conditions fertilizer may
be used to secure an immediate increase in production. Numerous
experiments show that the yield of corn, cotton, hay or other
crops may be increased from 50 to more than 200 present by
one application of fertilizer "
Thus fertilizer pla. an important role in a good land man-
agement program

Organic Matter
The solid part of soil is composed of organic and inorganic
material Inorganic matter is obtained from the decomposition
of the parent rock lhich supplies phosphorous, potassium, cal
cium. magresiumo and other essential mineral elements.
Organic constituents of the soil are obtained from living and
dead plants and animals plant roots, green manuring crops,
manure, crop residues, fungi, bacteria, worms and insects. Soil
humus, commonly referred to as organic matter, represents an
advanced stage in the decomposition of organic material. The
importance of organic matter in the soil cannot be stressed too
strongly for it truly provides the "life of the soil "
Organic matter supports soil bacteria and fungi and thereby
enhances the bringing of insoluble soil minerals into solution, it
improves the physical condition of the soil, it increases water-
holding capacity: it improves aeration, it regulates soil tempera
ture and serves as an important source of nitrogen and other
plant food elements
Much of our land has been seriously depleted by organic mat-
ter, chiefly because of cultivation Large, unnecessary losses are
caused by "burning over" land and by burning crop residues.
We cannot improve and maintain the productivity of our soils
without regularly replenishing organic matter.
Practices for maintaining and replenishing organic matter
include- (1) Growing sod, cover and green manure crops (2)
Conserving and applying manure (3) Conserving and applying
crop residues.

Crop Rotation
Crop rotation is the systematic growing of a regular succession





SOILS AND FERTILIZERS


of different crops on the land. This plan has many advantages
over a one-crop system or a haphazard change of crops.
Good crop rotation is an important step in a land manage-
ment program. It helps to maintain and increase soil produc-
tivity and makes for a more prosperous agriculture. Good rota-
tions make maximum use of legume and sod crops.
There are many crop rotation systems which can be followed.
The choice of any particular rotation will depend upon the type
of farming, soil, climate, crops, market, labor and likes and dis-
likes of the individual.
Advantages of a good crop rotation:
Insures against total crop loss in any one year.
Utilizes farm labor more efficiently.
Replenishes organic matter and where legumes are used
supplies additional nitrogen.
Reduces erosion losses.
Increases utilization of native soil fertility.
Reduces plant diseases, insects and weeds.
Improves physical condition of the soil.
Makes fertilizer and lime more effective.
Any farmer can supplement his own experience in selecting the
best rotation for his particular needs by consulting with his state
agricultural college, vocational teacher, county agent, or other
agricultural agencies.

Soil Reaction and Liming
Most soils in the humid regions are acid or "sour" as a result
of losses by leaching and crop removal of such basic elements
as calcium, magnesium and potassium. In arid or semi-arid
regions soils are usually alkaline or "sweet".
Limirg not only corrects soil acidity but serves as an econom-
ical source of calcium. Magnesium also is supplied when dolo-
mitic materials are used.
Nature has provided an abundant supply of liming materials
in most parts of the country. Limestone, hydrated and burnt
lime, marble dust, marl, chalk, oyster shells and industrial by-
products are the principal sources. Ground limestone is the most
abundant and widely used material. Limestones composed mainly





TIIE LAND AND ITS CARE


of calcium carbonate are called high calcium limestones; those
containing both calcium and magnesium carbonates are called
dolomitic limestones.
Most crops grow and produce best on slightly acid or neutral
soils. There are exceptions, however, such as blueberries and
cranberries which do best on strongly acid soils. Other crops such
as alfalfa and sweet clover have a high lime requirement.
Lime works as a team with fertilizers to produce higher yields
of better quality crops Liming without adequate fertilization
seldom is sufficient for satisfactory crop growth.

Living acid soils is a desirable practice because it:
Corrects soil acidity.
Supplies calcium and magnesium
Speeds tile decay of organic matter and the liberation of
plant foods
Increases the availability of applied and residual phos-
phate
Increases fixation of nitrogen by soil and plant organisms.
Improves crop yields.
Improves the physical properties of soils.
Reduces the activity of toxic substances in the soil.

The rate ard h equenei of linmng depend primarily upon the
acidity of the soil. the kind of soil and crops to be grown.

The degree of acidit? or alkahnity of a soil is conveniently
expressed in terms of pH values. The pH scale is divided into
14 divisions or pH units numbered from 1 to 14. Soils with a pH
value of 7 0 are neutral Soils with pH values below 7.0 are acid
or "sour" while those above 70 are alkaline or "sweet." A pH
of 5 0 is 10 times more acid than a pH of 6.0 and a pH of 4.0 is
10 times as acid as pH 5 0. Thus a soil having a pH value of 4.0
is 100 times as acid as one with a pH of 6.0.

The pII value of most soils falls in the range between 4.0 and
8.0. A pH value of 6 5 is desirable for most crops.

Testing soils for pH values is a relatively simple procedure for
determining the degree of soil acidity or alkalinity. Tests are
often made by vocational teachers, county agents, state colleges
and by fertilizer companies.






12 SOILS AND FERTILIZERS


The amount of liming material required to raise the pH value
of a soil one unit, such as from 5.0 to 6.0, depends largely upon
the type of soil, organic matter content and the fineness and
type of material used for timing. Clay and silt loam soils require
more lime than sandy soils. Likewise, soils high in organic matter
require more lime than those low in organic matter. The follow-
ing table may be used as an example:

APPROXIMATE AMOUNTS OF DIFFERENT LIMING MATERIALS
REQUIRED TO RAISE THE pH VALUE ONE UNIT
ON VARIOUS SOILS*

Crround hmestone
marl or Burnt Hydrated
Soil oy'ter shells Lime Lime
Ibs. s.lb bs.
per acre per ace per acre
Light Sandy ........ 1,5i)00 840 1,110
Sandy loams ......... .... 2.000 1,120 1,480
Loams ................. ...................... 3,000 1,680 2,220
Silt loams and clay loas ........... 3,500 1,960 2,590
For soils low in organic matter, reduce the above amounts 25 percent.
For soils high in organme matter, increase 100 percent

Liming recommendations are available in each state. Consult
your local authorities for specific information

Some soils are naturally alkaline, especially in the arid or
semi-arid regions. Other soils are alkaline because they have been
overhimed. Both conditions may prove unfavorable for best crop
growth. To make soils more acid the addition of sulfur is usually
recommended. In calculating how much sulfur is needed, figure
that one pound of sulfur will neutralize about three pounds of
calcium carbonate or ground limestone.

Nitrogen

Nitrogen in its pure state is a colorless, odorless, inert gas
and constitutes about 80 per cent of the air. Plants, other than
legumes, cannot use pure nitrogen, nor can it be put into fer-
tilizers in this form Pure nitrogen must be combined with other
elements before it can be put into fertilizers or used as a plant
food.

- Vusmia Experiment Station Bulletin 136.




Properly Balanced nutrients to Assure Satisfactory Growth


Substance Symbol

Water HO

Oxygen 0O

Ca bon C

Nitrogen N

Pl'osplhoris P


,'o'ssiiium K


Cal'imm Ca

Sulful S

Mdagnesieum Mig


Iron F'e

Minangaese MIn

Boion B

Zinc Zu


Copper


Pounds per Acre

4,300,000 to 5,500,000

6,800

5,200 Carbon or 19 000
Carbon Dioxide (CO()

130

22


110


37
22

33


Approximate Equivalent

19 to 24 inches of lain

Air 1i about 20% oxygen

Caibon contained In 4 tons
of coal

650 lbs of a 20%' nirogen
feidlizer

250 Ibs of 20% superphos
plate

220 lb,. of 60% mur;ate of
potash

100 bs of limestone

22 lbs of sulfu

183 IbI of magnesium
sulfate


2 10 lbs of iron sulfate

0 3 1 l of manganese sulfate


0 06

trace

trace


Y lb, of borax

Small amount of szne sul
fate

Small amount of copper
sulfate


Essential Plant
Food Elements


Hydrogen (H)
Oxygen (0)
Carbon (C)



Nitrogen (N)
Phosphoius (P)
Pota"m n (K)


Caliumn (Ca)
Maignci mL (Mg)
Sulfur (8)



Boron (B)
Manganese (Mn)
Copper (Cu)
Zinc (Zn)
Iron (Fe)


95% to 98% of all plant growth is due
to these elements which come from
the air and water.



The Primary Elements needed by
crop in large amounts have long
been recogmned as the plant foods
most likely to be deficient in soils.


the Secondary Elements also are
needed by plants in relatively large
amounts and may be deficient in



The Minor Elements are required by
plants in small quantities and may
be deficient in soils.


* Includes grain, stover, and roots.
Ba-ed on information from Purdue University The composition of corn will vary depending upon local conditions










APPROXIMATE AMOUNTS IN POUNDS PER ACRE OF THE COMMON PLANT FOODS REMOVED BY CROPS

PRIMAn Y PLANT Foos SEcoNDARY PiTANT FOOD
Acre Phosphoric Calcaum Magnesia
CROP Yield Nitrogen Acid Potash Oxide Sulfur
(N) (PO.) (K,0) (CaO) (8) (MgO)
Grain Crops:
Barley (grain)............ 30 bu. 27 12 12 2 2 3
Barley (straw) ... tons 9 3 19 7 4 2
Corn (ear) ... .... 60 bu. 57 24 20 1 5 6
Corn (stover) .............. 2 tons 36 16 46 23 6 5
Cowpeas (gram) .......,,. 15 bu. 34 9 13 2 2 3
Oats (grain)... ........... 50 bu. 32 13 9 3 3 3
Oats (straw) 1 ton 12 4 30 10 4 3
Rye (grain) .. 30 bu. 32 2 10 1 1 2
Rye (straw) ... 15 tons 14 8 24 14 5 4
Soybeans (grain) 20 bu. 70 16 30 3 5 5
Wheat grain ) ..... 2. 5 bu. 28 13 8 1 2 3
Wheat (straw) ... 1 ton 10 3 15 6 4 2


Hay Crops:
Alfalfa Hay ...
Bluegrass Hay.
Clover Hay.....
Cowpea Hay...
Soybean Hay...
Timothy Hay....


...........






Fruits and Vegetables:
Apples (fruit) 300 bu. 17 5 19 2 6 4
Beans (seed) 25 bu. 54 12 21 4 3 4
Cabbage (heads) 10 tons 60 20 80 11 16 4
Onions (bulbs) 600 bu. 92 45 87 15 29 12
Peaches (fruit) 500 bu. 30 10 88 4 4 8
Potatoes (tubers) 300 bu. 63 27 90 5 7 12 q
Spminach (tops) 500 bu. 44 14 21 12 4 8
Sweet Potatoes (loots) 300 bu. 40 17 84 8 7 17 =
Tomatoes (fruit) 8 tons 32 11 56 9 2 6 t
Turnips (roots). 400 bu. 51 31 69 16 16 7
Other Crops:
Cotton (lint and seed) 1500 lbs 40 16 16 5 5 9
Cotton (stalks, leaves, and burs) 2800 lbs. 35 10 38 84 7 15
Peanuts (nuts) 2000 lbs. 65 15 20 5 5 5
Peanuts (vines) 2 tons 80 10 80 55 15 25
Sugar Beets (root) 15 tons 76 23 60 31 5 12
Tobacco (leaves) 1000 lbs. 44 5 58 63 6 9
Tobacco (stalks) ... 450 lbs. 15 3 20 12 2 3
Animal Products: Do
1000 Ibs of milk takes off the farm 5 6 2 2 1 8 1 7
1000 lbs of beef (live weight) takes off the farm 27 16 9 2 3 18 6 ....
-- a





SOILS AND FERTILIZERS


Most of the nitrogen in soils is found in the organic matter
which in turn is found largely in the topsoil, or plow layer. As
soils of the earth vary in their organic matter content, so also do
they vary in their nitrogen content. In the United States the
nitrogen in the topsoil varies from over 7,000 pounds to less
than 1,500 pounds per acre.
Fortunately, we have unlimited resources of nitrogen. In the
air over every acre there are 35,000 tons of nitrogen that can
be utilized by either synthetic nitrogen fixation processes or by
properly inoculated leguminous plants, such as clover and
alfalfa. Legumes, when inoculated and supplied with proper
nutrients, have the ability to take nitrogen from the air and
convert it into plant food.
Small quantities of nitrogen are obtained by the fixation of
nitrogen in the soil by certain bacteria. Rain and snow also
wash small amounts of nitrogen from the air into the soil
Nitrogen is quickly exhausted from our soils by erosion,
leaching and by growing crops which require relatively large
quantities. Therefore, nitrogen must be replaced frequently to
maintain soil productivity.
NITROGEN
Gives dark green color to plants.
Promotes leaf, stem, and fruit or seed growth.
Improves quality of leaf crops
Produces rapid growth.
Increases protein content of food and feed crops.
Feeds soil microorganisms during their decomposition of
low-nitrogen organic materials
Plants can use nitrogen when it is properly combined with
oxygen or hydrogen. In these combined forms it is known as
nitrate (NOa) or ammonia (NHI) nitrogen. Nitrogen in organic
matter is changed by biological action into the ammonia and
nitrate forms All nitrogen in the soil is subject to a gradual
change by soil microorganisms into nitrate nitrogen.
Nitrogen in the nitrate form is very quickly available to
plants and also is subject to movement up or doin in the soil
in the capill]iy viter and to loss bl leaching. In the ammonia
form, it is not quite so quickly available to plants and is more
tightly held by the soil particles thus being more resistant to





. AND ITS CARE


leaching Most plants grow best when they have available in
the soil both of these forms of nitrogen.
Nitrogenous fertilizer materials are obtained from synthetic
process, natural mineral deposits, by products and organic
sources
Very large amounts of atmospheric nitrogen are converted by
synthetic processes into various fertilizer materials such as
ammonium nitrate, sulfate of ammonia, cyanamid, urea, am-
monia solutions and nitrate of soda. During World War II, our
synthetic nitrogen production capacity was greatly expanded
to make ammunition and fertilizers. Many of these plants have
been wholly converted to fertilizer manufacture, with ammonia
and ammonium nitrate being their chief products
The use of nitrogen in solution form has been found very
satisfactory in compounding fertilizers. Solutions of ammonia
with ammonium nitrate or urea are widely used These ammon-
iating solutions are of high nitrogen content.
Practical methods have also been devised for introducing
ammonia and ammonia solutions into irrigation water. In some
areas, anhydrous ammonia or solutions are applied directly to
the soil.
Nitrate of soda from deposits in Chile long has been an
important source of nitrogenous fertilizer and is imported into
this country in large quantities. Synthetic nitrate of soda also
is available for fertilizer use Most of the nitrate of soda used
in the United States is applied as a side or top dressing to the
growing plants. It is quickly available to plants and is quite
mobile in the soil

Nitrogen as sulfate of ammonia is obtained in large quantities
as a synthetic material and as a by-product of the steel, gas
and coke industries.
Organic nitrogen for fertilizers is derived mainly from plant
and animal by-products, such as guano, dried blood, slaughter-
house tankage, seed meals, garbage tankage, fish meal and
others. The use of such organic materials in fertilizer is relatively
small in most areas because of the high cost per unit of nitrogen.
Farmers can add substantial quantities of organic nitrogen to
their soil by judicious use of cover crops and by returning all


THE LAND





SOILS AND FERTILIZERS


crop residues to the soil. The low-nitrogen organic materials,
such as straw and corn stalks, need extra nitrogen in the soil
during their decomposition, but all of the nitrogen they contain,
as well as any added to speed their decay, is ultimately made
available to crops.
About one-half of the fertilizer nitrogen used in the United
States is applied to the soil as separate materials.
Following are the most common forms of commercial
nitrogen

Following Are the Most Common Forms of Commercial Nitrogen:

Nitrates (NO,)...... Nitrate of Soda
Ammonium Nitrate
Nitrate of Potash
Ammonia (NH)... Ammonium Sulfate
Ammonium Nitrate
Ammonium Solutions
Anhydrous Ammonia
Ammonium Phosphate
Synthetic Organic ..... Calcium Cyanamide
Urea Fertilizer
Natural Organic......... A. Vegetable Organic, such as cottonseed
meal, soybean meal,castor pomace, etc.
B. Animal Organics Fish meal, animal
tankage, etc.


Phosphoric Acid
Phosphorus, in its pure state, is a very reactive substance
that bursts into flame when exposed to the air. Phosphorus
must be combined with other elements to curb its violence
before it can be put into fertilizers or used as a plant food.
Many of our soils are deficient in phosphorus and respond to
phosphate fertilization On the average, for example, the phos-
phorus content of our surface soils is only about one-half that
of nitrogen and one-twentieth that of potassium.
The native phosphorus in soils, in the vast majority of cases,
is "bound" or "fixed" in very insoluble forms so that only a
very small part of the total supply becomes available in any
one cropping season. For this reason, even soils with a high





AND ITS CARE


total phosphorus content often fail to provide available supplies
adequate for maximum crop production
The importance of phosphorus in crop production is em-
phasized by the fact that unsatisfactory plant growth more
often is due to a shortage of this element than of any other
plant food. Phosphorus is intimately associated with all life
processes and is a vital constituent of every living cell Without
phosphorus there could be no ife.

PnosPHORUs-
Stimulates early root formation and growth
Gives rapid and vigorous start to plants.
Hastens maturity.
Stimulates bloomiing and aids in seed formation.
Gives winter hardiness to fall-seeded grains and hay cops.
In fertilizers, phosphorus is guaranteed in the form of phos-
phoric acid (PeO,). Phosphate materials, mostly calcium salts
of phosphoric acid, represent more than one half of the total
fertilizer tonnage used in the United States
This country is fortunate in having over half of the total
known world supply of phosphorus-about 15 billion tons-in
the form of rock phosphate deposits. About 40% of our rock
phosphate supply is in Florida and Tennessee and 60% in the
Rocky Mountain states where deposits are just beginning to be
tapped. It is estimated that we have in known deposits sufficient
phosphates to last us for more than 2,000 years
Superphosphate is the principal carrier of available phos-
phoric acid, this material alone accounting for more than 90%
of all phosphoric acid guaranteed in fertilizers. Superphosphate
is made by treating phosphate rock with sulfuric or phosphoric
acid. Current production in the United States is approximately
10,500,000 tons annually, an increase of over 100% since 1940.
Ordinary superphosphate makes up the greater part of the
total superphosphate tonnage It has an available phosphoric
acid content of 18% to 20% and, in addition, supplies 20 pounds
of calcium and 12 pounds of sulfur with each unit (20 lbs ) of
P2Os. In 1947, about 2,000,000 tons of ordinary superphosphate
were applied directly to the soil as a separate material
Double superphosphate (sometimes called triple or treble)


THE LAND





SOILS AND FERTILIZERS


contains 40% to 50% available phosphoric acid but only b
pounds of calcium and 0.5 pounds of sulfur per unit of P2O,.
While a newer material than ordinary superphosphate, double
superphosphate has been produced commercially in the United
States for over 50 years, with the greatest expansion taking
place since 1930. This material is used principally in formulating
high analysis fertilizers
Other phosphate materials used as fertilizers are:
Phosphate rock for direct application. The finely ground
product is applied directly to the soil in considerable quantities
in some farming areas. Such applications serve their principal
purpose in building up the phosphoric acid levels in soils in
long-time soil improvement programs, rather than as a substitute
for the more soluble forms of phosphorus.
Basic slag. This is a by-product of the basic open hearth
process of making steel. The quantity produced in the United
States is limited and all of it is used for direct application to
the soil.
Ammonium phosphate. This product supplies both nitrogen
and available phosphoric acid. Ammonium phosphate is manu-
factured in this country and also is imported.
(alcium metaphosphate, potassium metaphosphate and alpha
phosphate. These are all relatively new materials in which com-
mercial production either has not started as yet or is just
getting under way.
Potash
In its pure state potassium is highly reactive and dangerous
to handle. It must be combined with other elements before it
can be put into fertilizers or used as plant food. In fertihzers
potassium is guaranteed as potash (K20).
The soils of this country are far richer in potash than in
nitrogen or phosphoric acid. The surface 6 inches of our crop-
land contains about 5 billion tons-or as much as the total known
world deposits of water soluble potash salts. Unfortunately, most
of the potash is locked up in the soil in forms that plants cannot
readily use. A soil may have a total of 40,000 pounds of potash
per acre stored within the plow depth, but only a small amount
may become available to plants in any one cropping season.
PoTAsn
Imparts increased vigor and disease resistance to plants.





TllE LAND . AND ITS CARE 21

PI' lices s1tong, stiff talks, thus reduces lodging.
Increases plulmpness of the grain and seed.
IE's.entl to ilt formation and transfer of starches, sugars
and oils.
I llipall't w inler hardiness to legumes and other crops.
\We i .ne, il til- cotntr. known commercial potash deposits
srffn-int It last or several generations with more resources
still to be evaliuaed. There are close to 5 billion tons of foreign
depoi avil aiable to siippleiiient our domestic supplies.
Prili to WorllV War T, Amelrican agriculture was entirely de-
pendent on foreign soirCes for its potash. When the war cut
off tni'-e supplih in intensive search was made to locate
solurcs in this cotllltr' As Ia resllt. potash began to be produced
here in 1,i15 aid production i continued oil a moderate scale at
Trona, California, from brines of Searles Lake even when im-
ports were resuIed.
In 1931 shipment, were made from the newly discovered
potasll delpits near ('arlsbad. New Mexico. Production increased
rapiltl until at the outbreak of World War II about half of the
potash consumed l(eie was1 of Animrican origin. Since 1938, brines
of the Saldu rn Marsh itn it:al and subsequently brines in eastern
Michigan also have been used as sources of potash.
Imports again were rut off during World War II, while
demand soared due to the huge war-food program and high
industrial activity. The American potash industry immediately
expanded its mines and refineries to meet these needs and has
continued to increase production in the post-war period.
The American potash industry is now delivering over a
million tons of potash (K,0) a year for agricultural and in-
diustral aus. This is more than double tlhe potash used for all
purposes in North America from both domestic and foreign
sources before World War II. American agriculture and in-
dustry now have been made independent of foreign supplies.
Muriate of potash (60-62% K(O) is by far the most popular
fertilizer grade, accounting for 80' i of the potash used in
agriculture. This highly-refined material is over 98% pure
potassium chloride It supplies potash in the cheapest form
under most conditions. The 50% K2O grade of muriate of potash
accounts for about 6% of the potash used, manure salts (22-
30:; KzO) make up 3%. while sulfate of potash (50% K20)





SOILS AND FERTILIZERS


and sulfate of potash-magnesia (22-26% KO2) supply about
8% of the fertilizer potash.
Potassium nitrate, vegetable meals, tobacco stems and by-
product potash from the cement industry provide additional
sources.
Potash is applied to soils both in mixed fertilizers and as
separate materials.

Secondary and Minor Plant Foods
Until recent years little attention was given to the importance
of tie secondary and minor elementscalcium, magnesium,
sulfur, boron, manganese, copper, zinc and iron-in fertilizers.
It was thought that most of our soils contained sufficient
natural supplies. Also, commercial fertilizers supplied consider-
able quantities of these elements as impurities and carriers of
other plant foods.
The development of more highly refined materials carrying
more nitrogen, phosphoric acid and potash has reduced the
supplies of some secondary and minor elements in fertilizers.
Also, with intensive cropping, greater emphasis on higher yields
per acre, and with our soils becoming older and more depleted,
the need for all essential elements becomes more pronounced.
It is now known that poor yields often are due to deficiencies
of one or more of the secondary or minor elements. Therefore,
for most profitable crop production more and more attention
must be given to these plant foods.
SECONDARY PLANT FOODS-
Calitum: Calcium is found abundantly in various limestones,
oyster shells, phosphate rock, superphosphate and gypsum.
Promotes early root formation and growth.
Improves general plant vigor and stiffness of straw.
Influences intake of other plant foods.
Neutralizes poisons produced in the plant.
Encourages grain and seed production.
Increases calcium content of food and feed crops.
Magnesium: Magnesium is found in dolomitic limestone, mag-
nesium sulfate, sulfate of potash-magnesia and magnesium oxide.
Aids in maintaining dark green color of leaves.
Regulates uptake of other plant foods.





THE LAND . AND ITS CARE 23


.Acts as carrier of phosphoric acid in the plant.
Promotes the formation of oils and fats
Plays a part in the translocation of starch.
Sulfur The chief sources of sulfur for crop use are natural
sulfur and sulfur obtained from fertilizer materials such as
gypsum, ordinary superphosphate, sulfate of ammonia and
sulfate of potash Considerable sulfur liberated into the atmos-
phere in the burning of coal is returned to the soil in rain-
water
Gives increased root growth
Helps maintain dark green color.
Promotes nodule formation on legumes.
Stimulates seed production.
Encourages more vigorous plant growth.
MINOR PLANT Foos-
The minor plant food elements, also called "trace elements,"
are boron, manganese, copper, zinc and iron. Although relatively
small quantities are required, all are necessary for plant growth
Much attention now is being given to these elements and their
importance in plant nutrition.
Unsatisfactory plant growth in many areas is traceable to the
lack of one or more of these minor elements. Lack of boron, for
example, may adversely affect yields of alfalfa and other crops.
Deficiencies of these minor elements in soils are not so wide-
spread as to warrant their general additions to all fertilizers.
When deficiencies do exist in soils, the) can be conveniently
corrected by the addition of these elements to commercial
fertilzers
In some eases minor elements also are effectively used as
separate materials applied to the soil and as a spray applied to
the growing crop.
With some of these elements the range between beneficial and
detrimental amounts is very narrow so they must be carefully
used, for too much will cause injury.
Such other elements as sodium, chlorine and molybdenum
affect plant growth, although they are not now classified as
essential plant foods. This is especially true for sodium which
on some crops and under some conditions seems to serve a specific
function of its own in promoting plant growth. On other crops
and under certain conditions it has the ability to substitute for
a portion of the potash requirements








AVERAGE COMPOSITION OF THE COMMON FERTILIZER MATERIALS


Fertilizer Materials





Ammonium Nitrate ,
Ammniom Phosphates
Ammoniate d Superphoaphate

Anhydrous Ammonia
Aqua Ammonla
Basic Slag
bone Meal-Steamed

Bone Meal -Rw,
Calcium Metapihosphat
Calcium Nitrate
Caslr Bean Pomace .







Cyanamid
Dolomite
ih hBrap. .. ... .


Type





Syntheti
Man ufatur ed
Manufactured

Synthetic
Synthetic
Manurfacured
Animal

Animal
Mannuctured
Synthetic
Vegetable

Vegetable

Vegetable


Syothetic
Natural
Animal


Equivalent Acidity or
Basieity per Ton of
Available Water Material
Total Phosphonlr Soluble Total Tota Total Total Ridual (Exprsed as ponds
Nitrogen Acid Potash Calcium Mageia Sulfate Ohlorine Effect calcium arbonate
(N) (PaO) (K20) (CiO) (MgO) (SO ) (CI) UEpo equivalent)
% % % % % % % Sol ,-
Equivalent Equivalent
Acidity Alkalinity

35 .Acd 1200
11-i1 20-48 2 0 0,5 6 5 ACId 1450
2-4 18 23.0 0,5 2 0 0 3 S lightly 140
( Acid
82 Acid 2069
25 Acid 900
8-12* Alkalmno


0.A





MagnesumO(de .. Natural ... .. .......... 5.0 92.0 ....... .... Alkle ..............

Magnesium Sulfate. . Natural .... .. 30-33 .. ..... Neutral.......
Maure Sals .. Natural ... . 20-0 0.5 I 5 I.0 54.0 Neutral
Murate of Potash ..... Natural 0-02 0 5 0 5 1.5 48.1 Neutral ..
Nilrutc of Soda N(aLural & Synthetic 10 ., ., .. 0. Alkli nI ..o 5
Nttrate of iPoLh .,, Maniufictured 13 44 0 6 0 5 0,1 0 5 AInlnmo 480
MNtrogen Solutions ,, Synthetic 37-46 ... ... .. ... Acid 1160
Rock Ph bate .. .. Natural 32u36' 0 8 0 2 0 -. Alkalo ........ m I-

Soybean Meal .... geble 7 0 1 2 l.5 0 5 0.5 0.5 Slightly 33
SAlkaline
Sulate of Ammona .... Jy-Product and 20 50.0 0 Ad 2200
Synthetic
Sulfateof Potash .. ... Natural .. 5 ...... .. ....... .. Ntral
Sulfate of Pota) -Maglsia .... Natural .. ... 22 2.0 18-S 45 5 2 2 Nutr.al

Superbhoap*ate (double or triple). Muaufactured 32-50 20,0 0 5 3 0 Neutral
Suprr phphatl (ordlary or normal) M anufactured 18-20 .,,, 25.0 0.5 20 0 0 3 Noutral
Tui kage (animal)... ... Anmal 7 8 10 1, 15 5 0 6 1.0 0.7 Alkae ,. 240
Tikage (orbage) ...., .. Vtgetable 2-3 1-3 1-2 4 5 0 5 1.0 1.3 fSlightly .. 134
lAlkalme

Tankage (prenac) Animal 0- .. ... .. ... Acid 320
TobaccoSte ......... Vegetable 1.5.5 5 6-10 5 0 06 ] 0 1 2 Alkaline ,., W
U)re .. Synteotir 42-47 .. .. ..i. ..,,. .. Acid 1500

Bor ....... 11% Boron .
Coppr Sulate ..... 2% CU ....... .. ... .. .... .. ..
IrM Sulate.. ..... 2 e .
Ma ae Slat ... 24% M ... ... ......... ......... .. .. .
Bodium Chli ....... 39% Na
Sinc Sulfate ...., ,, 25% Zn


* Total PDO.






SOILS AND FERTILIZERS


Form Manure
More than one billion tons of manure are produced by the
farm animals of the United States every year. If all of it were
saved and properly used, it would have tremendous value.
Usually less than one-half of the actual value of manure is
realized because of improper handling and storing. These losses
vary widely from farm to farm and from region to region.
Natural* these [o.es can be materially reduced by proper man-
agement in the barn and in the field.
Animal manures are poorly balanced in their plant food
content, being relatively high in nitrogen and potash but low
in phosphoric acid. The addition of superphosphate to manure
not onlu improves plant food balance but helps to conserve
nitrogen and aids in barn sanitation

MANURE HAS A THREE-FOLD VALUE:

1. Organic Matter Manure supplies valuable organic matter to the soil
and organ matter improves soil tilth, increases
water-holding capacity, improves aeration, regu-
lates soil temperature and has a beneficial effect
on sodi micro-organims.
2. Plant Food A ton of fresh manure contains about 10lbs. of nitro-
gen. 5 Ibs. of phosphoric acid (POd) and 10 lbs. of
potash (KsO) and important quantities of other
plant food elements. Nearly half of the plant food
value of manure is in the liquid portion.
3. Growth-Producing Certain organic constituents (hormones) of manure
Substances are valuable in promoting and stimulating plant
growth.


PROPER HANDLING IMPiROVE VALUF
Conserve the value of manre by:
Using enough bedding to absorb the liquid manure because
of its high fertilizing value.
Spreading as quickly as possible after it is produced and
incorporating it into the soil.
Storing in a covered building or shed and compacting it
so that air is excluded
Adding superphosphate to conserve nitrogen and balance
its plant food content Adding 2 to 21/2 lbs. of super-
phosphate per day (50 to 100 lbs. per ton of manure) for





AND ITS CARE 27


each horse, cow or steer is a recommended practice Add
100 lbs. per ton of flesh poultry manure

COuMPosITroN orF MAN.TIn s
The composition of various manlure is shotlii below Recog-
nition should be given to the fact that the composition varies
widely under different conditions and methods of handling.

PLANT NUTRIENTS IN ONE TON OF DIFFERENT MANURES
(Includes sohd, liquid, and bedding)

Nitrogen Phosphoric Acid Potash Tons Manure
Kind of (N) (PO0) (K ) Produced per Year
Animal Pounds Pounds Pound 1000 ls. Live Weight
Horse 13 2 5 1 12 1 12
Cow 11 4 3 1 9 9 15
Pig 9 9 6 7 9 3 18i4
Sheep 15 8 67 18 0 9%
Steer 15 0 6 0 8 0 9
Hen. 21 0 16 4 10 2 42
Duck 11 4 28 8 9 8

Source: Cornell University

Factors Influencing the Use of Fertilizer
The U S. Department of Agriculture reports the major
factors influencing consumption of fertilizer are (1) native soil
fertility, (2) the farming system, (3) farm income. (4) fertilizer
prices and (5) research and education

NATIVE SOIL PER'IILITY
The natural fertility of the soil- whether it was rich or poor
in the beginning is an important factor in determining the
need for fertilizers Obviously, poor soils need fertilizers sooner
than the richer, mole feitile soils and the rate of fertilization
varies with the fertihty. Soils are constantly changing and differ
widely in fettility More and movie of the soils in our best
farming regions are shooting a need for fertilizers

THE FARMINIO S1STi-M
Farming systems greatly influence the use of commercial
fertilizers. Under a livestock system a substantial quantity of
plant food is usually returned to the soil in the form of manure
and crop residues Under a cash crop system much of the produce


THE LAND .





SOILS AND FERTILIZERS


is sold off the farm directly and carries with it large amounts
of plant food.
The crop itself influences the use of fertilizers. Some crops
have high plant food requirements while the needs of other crops
are comparatively small. Also, some plants have extensive root
systems and are vigorous foragers while others are relatively
weak in this respect. In addition, the different crops show ex-
tremely varied responses to individual plant foods.
The commercial value of crops greatly influences fertilizer
usage. For example, more fertilizer is used per acre on such
high-acre-value crops as tobacco, citrus and potatoes than on
low-acre-value crops The natural tendency is to fertilize most
heavily those crops that yield the greatest financial return per
acre.
Many factors such as the development of hybrid corn, better
cultural practices, better disease and insect control and other
improved practices have resulted in increased crop yields, but
at the same time have resulted in a greater removal of plant
foods which must be replaced.

FaR INCOME
Recent studies, over a 32-year (1911-1943) period, show that
farmers' expenditures for fertilizer vary with their previous
year's income. Farmers buy more fertilizer following years of
high income and less following years of low income, the ten-
dency being to follow the fluctuations of their pocketbooks
rather than the needs of their soils.
Better farmers recognize the economy of a consistent fertilizer
program. They maintain a plant food level consistent with
profitable crop production, realizing that failure to fertilize
adequately during one season merely increases the need during
the following season.
FERTILIZER PRICES

In comparison with other commodities farmers buy, fertilizer
prices are relatively low.
The discovery and use of new materials, technological ad-
vances and competition have made possible substantial reductions
in fertilizer prices over the past quarter century. Following
World War I in 1919, a unit of plant food cost farmers an





THE LAND ... AND ITS CARE


average of $4.66. At the close of World War II in 1945, a unit
of plant food cost farmers an average of only $1.78.
Fertilizer now contains about 50 per cent more plant food
than it did 25 years ago and sells for considerably less.
The relatively low cost of fertilizer makes it possible and
profitable for farmers to purchase the quantities of plant food
needed for maximum crop production.

RESEARCH AND EDUCATION
Research and educational programs have been major factors
affecting the accelerated use of fertilizers.
Continued close cooperation in both research and educational
programs among State and Federal agricultural and educational
agencies, farmers and the fertilizer industry will add much more
to our knowledge of soil fertility and fertilizer use. Some of the
outstanding results already achieved have brought:
Better understanding of plant food deficiencies and how
to correct them.
Development and use of higher analysis fertilizers.
Development of new fertilizer materials.
Manufacture of fertilizers to overcome specific plant food
deficiencies.
Improved fertilizer placement and better farm machinery
for placement.
Higher percentage of plant food in fertilizers.
Vocational teachers, county agents, extension specialists, con-
servationists, fertilizer representatives and others spreading the
knowledge gathered through research have increased the efficient
use of fertilizers and created a better understanding of the
profits to be derived from such use.
The potential producing powers of our soils can be realized
only with vigorous and intensive research and educational
programs.

Determining and Correcting Plant Food Deficiencies
Agricultural workers long have sought dependable methods
for determining plant food deficiencies in soils as an indication
of the plant food needs of crops.





SOILS AND FERTILIZERS


Each farm and even each field presents an individual problem.
Farmers today are greatly in need of accurate information so
that fertilizer can be used most effectively and profitably. In
many cases general information based on soil types or large
areas is not sufficient to give the specific information needed
by the individual farmer.

SOME METHODS Now USED TO DETERMINE PLANT FOOD
DEFICIENCIES*
External plant deficiency symptoms.
Laboratory methods:
1L Chemical analysis of soils and plants.
2. "Quick" soil and plant tissue tests.
3. Biological tests of soil.
Greenhouse tests.
Field plot experiments.
Farmers can conduct experiments in the field and observe
plant deficiency symptoms but usually technical assistance is
needed in making and interpreting the chemical and biological
tests.

PRACTICAL SUGGESTIONS FOR CORRECTING PLANT FOOD
DEFICIENCIES:
Follow the fertilizer recommendations of your state agri-
cultural experiment station and college.
Consult the vocational teacher, the county agent or the
extension specialist.
Local fertilizer dealers and agents can render valuable
assistance on questions relating to fertilizers.
Talk with successful neighboring farmers who have similar
conditions.
Plants show hunger signs which can be detected by careful
observation and study While these signs are definite, in many
eases considerable experience is necessary for their recognition
and proper treatment.
A disadvantage of this method of diagnosis lies in the fact
that it may reveal deficiencies too late for effective treatment
of current crops. This information can be used, however, in
preparing for the following season. Some common hunger signs
are as follows.




TIE LAND .AND ITS CARE 31

NITRO(IN DEFI'1IENCY
A sickly yellowish green color.
A distinctly slow and dwarfed growth.
Drying up or "firing" of leaves which starts at the bottom
of the plant, proceeding upward. In plants like corn,
grains and grasses, the firing starts at the tip of the
bottom leaves and proceeds down the center or along
the midrib

PnosPOllou DEIB'lEN( y
Purplish leaves, stems and branches.
Slow growth and maturity.
Small slender stalk in case of corn. In small grains, lack
of stooling.
Low yields of grain, fruit and seed.

PoTASH DEFICIENCY
Mottling, spotting, streaking or curling of leaves, starting
on the lower levels.
Lower leaves scorched or burned on margins and tips. These
dead areas may fall out, leaving ragged edges. In corn,
grains and grasses firing starts at the tip of the leaf
and proceeds down from the edge. usually leaving the
midrib green.
Premature loss of leaves and small. knotty poorly-opened
bolls on plants like cotton.
Plants, like corn, falling down prior to maturity due to
poor root development.

CALCIUM DEFICIENCY
Young leaves in terminal bud become "hooked" in appear-
ance and die back at the tips and along the margins.
Leaves have wrinkled appearance.
In some eases, young leaves remain folded.
Light green band along margin of leaves.
Short and much-branched roots.

SULFUR DoFICIENCY
Young leaves light green in color, have even lighter veins.
Short, slender stalks.
Slow, stunted growth.





SOILS AND FERTILIZERS


Spotting of leaves, as with potatoes.
Immature fruit, light green in color.
MAGNESIUM DEmICIENC
A general loss of green color which starts in the bottom
leaves and later moves up the stalk. The veins of the
leaf remain green.
Cotton leaves often turn a purplish-red color between
the green veins.
Weak stalks with long branched roots.
Definite and sharply defined series of yellowish-green, light
yellow, or even white streaks throughout entire leaf as
with corn.
Leaves curve upward along the margins.
MINOR PLANT FOOD DEFIcOENOIES
Boron need is indicated by cracked stem of celery, brown
rot of cauliflower, dry rot of sugar beets, heart rot of
turnips, yellow tip of alfalfa, corky core of apples and
black heart of table beets.
Manganese deficiency is shown by pale green to yellow and
red colors between green veins of leaves of tomatoes and
beets, resinous spots on leaves of citrus, chlorosis of crops
such as spinach and soybeans on overlimed soil, and
"gray speck" on oats.
Copper deficiency causes die-back in citrus and, on muck
soils, blasting of onions and truck crops.
Zinc deficiency is indicated by white bud of corn, rosette
of pecans and little leaf of fruit trees.
Iron need is shown by pale-yellowish color foliage, in the
presence of adequate amounts of nitrogen and on soils
that are high in lime or manganese.

Methods of Applying Fertilizer
There are many ways of applying fertilizer, each of which
has its advantages. The method to be used depends upon the
crops, soil, climate, date and rate of application, kinds of fer-
tilizer and equipment available. The aim should be to get the
fertilizer in the soil where it will do the most good.
BANDING ALONG THE ROW:
Distributing the fertilizer in bands one or more inches wide





THE LAND . AND ITS CARE 33

on either or both sides of the row while planting, usually at or
below seed level.

DRILLING WITH ScEu:
Applying fertilizer in the row when the seed is drilled or
planted. This method should be used only with seed that can
tolerate contact with fertilizer, such as the small grains, and
usually relatively light rates of application are used.
BRoADCASTINo BEFORE PLOWING *
Spreading fertilizer uniformly over the field. Plowing mixes
it with the turned layer. This method is well adapted for heavy
application of fertilizer, particularly when large amounts of
crop residues or cover crops are on the land.

BROADCASTIlN -AFTER ILOWINx
Spreading fertilizer uniformly over the field on the plowed
soil.

DEEP DRILING--AFTER PLOWING:
Placing fertilizer in bands at desired depths in the soil.

P WsoLE on DI-EP FURROW :
Putting fertilizer in a hand on the bottom of each furrow
before the next furrow is turned. Heavy applications can be
made this way. Fertilizer is placed deep in the soil and en-
courages deeper root growth.

SIDE DRESSING:
Putting fertilizer aloug the row after crops have started
growing. Often used on truck and other erops where large
amounts of readily available fertilizer, such as nitrogen, are
desired.

BEDDING :
Applying fertilizer in the bottom of the furrow, then bedding
or covering before planting.

STARTER SOLUTIONS:
Dissolving fertilizer in water and applying at the time of
transplanting various crops is a common practice. Solutions of
fertilizer also are applied as preplanting applications and as





SOILS AND FERTILIZERS


side dressings or top dressers for growing crops. Young plants
are easily injured by highly concentrated fertilizer solutions
so care should be taken when applying fertilizer in solution
form.

ToP DRESSING:
Applying fertilizer on the surface of the soil for pasture,
grassland, small grain, tree fruits and other crops.

IRRIGATION
Adding soluble fertilizers to irrigation water.

VARIATIONS:
Variations and combinations of these methods are often used.
Part of the fertilizer is sometimes placed on fields by broad-
casting, the remainder drilled in or banded; some may be
plowed under, the rest broadcast after plowing.
A new development is the direct application of anhydrous
ammonia to the soil This requires special equipment to with-
stand the pressure necessary to keep the ammonia in liquid
form.
Consult with your agricultural college, experiment station,
vocational teacher, county agent, or fertilizer dealer for best
method of fertilizer placement.

Fertilizer Production and Use
The nmaufactiure of fertilizer in the United States had its
beginning in a small plant in Baltimore in 1849 and today
represents one of the largest units of the heavy chemicals
industry.
Millions of tons of phosphate rock are mined each year from
deposits in Florida, Tennessee and the Utah-Idaho-Wyoming-
Montana fields. Tremendous quantities of sulfur are mined and
shipped from Texas and Louisiana to be converted into sulfuric
acid for treating rock phosphate to make superphosphate.
Millions of tons of crude and refined potash salts are shipped
from the mines and the refineries in New Mexico, Utah and
California. Millions of tons of nitrogen materials are produced
in this country or imported from other countries. Thousands
of additional tons of other fertilizer materials are shipped from
all parts of the country.





THE LAND . AND ITS CARE


These Imillio' ot tons of different fertilizer materials are
assembled in more than a thousand manufacturing plants located
throughout the United States. Some of the materials are pro-
cessed further while others are used without additional pro-
cessing in preparing mixed fertilizers and separate materials
for farmers.
Fertilizer factories represent investments of millions of dollars
and provide employment for thousands of people. The factories
vary in size from small plants whose operators purchase all of
their raw materials and mix only a few hundred tons each year
to huge factories with sulfuric acid and superphosphate
facilities for manufacturing many thousands of tons of mixed
fertilizers annually.
Storing, formulation, mixing, conditioning and shipping are
some of the important operations in the manufacture of fer-
tilizers Over 16 million tons of fertilizer were produced in 1947
-more than double the annual production prior to World
War II
Although fertilfieis have been manufactured for less than
100 years, the value and need for feeding plants to increase
yields have been recognized since the earliest recorded times.
The writings of the ancient Chinese, Greeks and Riomans reveal
the use of such fertilizers as were available. Some of the first
materials used as fertilizers were animal manures, wood ashes,
bones, fish. guano, wool waste, chalk and marl. Early New
England settlers found Indians planting a fish in each hill of
corn.
Lack of knowledge about the nutrients in manures and of the
importance and functions of different plant foods seriously
handicapped the farmers of that age As the years passed they
observed an apparent decrease in the fertilizing value of
manures The failure of manure to meet the needs of soils
remained a serious problem until it was discovered accidentally
that when hones were added to manure the crop responses were
greater. We now know that bones furnish phosphorus, one of
the most important plant nutrients in which manures were
deficient.
By the middle of the 19th century a commercial trade in bones
llad become well established Bones, however, did not prove fully
effective because it was soon realized that a more readily soluble





SOILS AND FERTILIZERS


source of phosphorus was needed. Attempts to increase the
solubility and therefore the effectiveness of the phosphorus in
bones led Sir John Lawes to experiment in England with treat-
ing these materials with sulfuric acid. The new product, called
"superphosphate", was an immediate success and is one of the
most widely-used products in the plant food world today.
Phosphate rock has now completely replaced bone as a source
of prosphorus in the manufacture of superphosphate.
The use of chemical plant food in the United States probably
dates back to 1830 when Chilean nitrate of soda was first im-
ported. Mixed fertihzer first was manufactured in the United
States in 1849. Superphosphate manufacture was begun at the
same time.
In the early years of the industry, fertilizers were composed
mainly of waste products from other industries: Blood, bones
and tankage from the meat packing industry, scraps from the
leather industry, fish and fish scraps, slops from the beet sugar
industry and meal residues from the vegetable oil industry.
Today, however, such materials have been replaced almost alto-
gether with highly-concentrated chemical compounds.
Fertilizers today are either separate materials for direct
application or carefully prepared mixtures of materials as-
sembled in accordance with definite formulas developed for
specific soils and crops as a result of years of experience and
research. In mixed fertilizers the materials are tested, accurately
proportioned, mixed, cured and remixed to assure uniformity
and good physical condition.

Services of the Fertilizer Industry
The services of the fertilizer industry are many and varied.
The most important service is the use of experience and technical
skill in bringing together the proper materials, of which there
is great variety, and blending them into products which give
farmers the best results and greatest economy.
A modern fertilizer factory requires special mills for grinding,
elevators, screens, mixers, air separators, cranes, automatic
scales, bagging and sewing machines, digging machines and
other equipment.
Extensive facilities are required for curing and storage of





TIE LAND . AND ITS CARE


materials and finished products so that the manufacturer can
supply fertilizers in good drillable condition the year around.
THE FERTILIZER INDUSTRY PERFORMS THESE FUNCTIONS:
Purchases in large quantities and brings together materials
from various parts of this country, as well as other
countries of the world. This involves handling millions
of tons of materials each year.
Supplies the scientific skill and experience to produce the
proper materials and mixtures recommended by the state
experiment stations, U.S.D.A., and others.
Maintainis chemists, agronomists and laboratories to test
materials and finished products.
Maintains plants for manufacturing which includes mixing,
curing, bagging, storage, and shipping.
Selects and trains dealers and agents who provide local
distribution.
Checks on results obtained by fertilizer users.
Disseminates information about fertilizers to farmers,
dealers, colleges, experiment stations, vocational teachers,
county agents and others interested in the use of fertilizer.
Cooperates with farm organizations, agricultural colleges
and other groups interested in maintaining and improving
soil productivity. An intensified and coordinated educa-
tional program between all agencies dealing with soil
problems is essential to maximum farm prosperity.
Conducts research within the industry to improve present
materials, develop new and better materials, conserve
natural supplies and improve methods of manufacture,
distribution and use.
THE INDUSTRY HAS MADE NOTABLE ADVANCES IN
RESEARCH SUCH As:
Nitrogen-In nitrogen production, the industry developed or
perfected for agricultural use, cyanamid (the first synthetic
nitrogen), synthetic ammonia, synthetic nitrate of soda, ammo-
niated superphosphate, urea fertilizer and the highly concen-
trated ammonia solutions.
Phosphate-In the phosphate field, the industry initiated
these developments: The flotation principle of phosphate re-
covery which has increased the nation's reserve supply of usable
rock phosphate; development and large scale production of






SOILS AND FERTILIZERS


phosphorus and phosphoric acid by electrical and blast furnace
processes; started production of double superphosphate in 1890;
and the first commercial production of defluorinated phosphate
rock in 1944.
Potash-The American potash industry has applied the latest
scientific methods in increasing production to meet our greatly
expanded potash requirements, making us independent of foreign
supplies. It has developed 62% muriate of potash, the most
concentrated form. It has investigated thoroughly the chemistry
of brines in order to use them successfully as a source of potash.
It was the first to apply the principles of flotation to the refining
of soluble salts, permitting more efficient and economical pro.
duction of concentrated potash fertilizers.
The industry has constantly endeavored to increase the value
of fertilizer. The nitrogen, phosphoric acid and potash content
of mixed fertilizer has increased 55.8% since 1920 and more
rapid progress is indicated for the near future. Non-acid forming
mixtures are produced which will not cause an increase in soil
acidity, even with long, continued use. The physical condition
of fertilizer has been improved by decreasing the moisture
content and controlling particle size, thereby improving drill-
ability and storage qualities.
The industry as a whole provides a good example of the
applications of science to the benefit of man.

What's In Your Fertilizer?
All mixed fertilizers and fertilizer materials have a guaranteed
analysis showing nitrogen, phosphoric acid and potash content
which is stated either on the bag or tag as required by state
laws.

The guaranteed analysis is simply a convenient method of
expressing chemically the content of certain plant foods. Nit-
rogen is expressed as percent nitrogen (N), phosphorus as per-
cent phosphoric acid (P205) and potassium as percent potash
(KsO), although these plant foods do not exist in such forms
in the bag. Thus a 5-10-5 grade of fertilizer would be guaranteed
to contain 5% nitrogen, 10% available phosphoric acid (P205)
and 5% soluble potash (KzO) or 20 pounds of guaranteed
plant food per 100 pounds.





THE LAND AND ITS CARE 39

The question naturally arises as to what constitutes the re-
maining 80 pounds in a 100 pounds of a 5-10-5 fertilizer and
why the 20 pounds of guaranteed plant food cannot be pur-
chased separately.
Farmers cannot use pure nitrogen, phosphorus or potassium
on their crops. Pure nitrogen is an inert gas. Pure phosphorus
and potassium are very active chemically and will burn if
exposed to the air and water. Therefore, these elements become
useful plant foods only when combined with other elements to
form compounds or materials suitable for use in fertilizers.
Those unrllmhiar ilth tihe composition of fertilizer frequently
consider the plant food content only in terms of the three most
common guarantees nitrogen, phosphoric acid and potash.
However, most mixed fertilzers containing from 20 to 30% of
these three major plant foods also carry approximately 30 to
40% additional plant food in the form of secondary and minor
elements.

It is now recogizenl that these secondary and minor elements
-calcium, magnesium, sulfur, boron, copper, manganese, iron
and zinc-are essential plant foods winch ale deficient in many
soils. These plant nutrients may be found in adequate quantities
in materials comitnonl~ used in the manufacture of fertilizers,
otherwise they must be added as separate materials. Boron, for
example, is supplied by adding borax and substantial amounts
of calcium anld sulfur are obtained by using ordinary 20%
superphosphate.

Materials that supply secondary or minor plant foods are
necessary parts of a good fertilier and should not be classed
as inert filler Por example, when dolonitic limestone is used to
make fertilizers neutral or non-acid forming and to supply addi-
tional quantities of calcium and magnesium, the efficiency of
the fertilizer is increased and valne is added. The same is true
for conditioning agents used to make fertilizer distribute evenly
and flow freely in the drill.

Higher Analysis Fertilizers
Money can be saved by buying fertilizer on the basis of the
cost per pound of plant food rather than the cost per ton. Pounds
of plant food-not tons of fertilzer-count on the farm.





SOILS AND FERTILIZERS


In the early days mixed fertilizers were made from industrial
by-products, waste materials, low grade superphosphate and
materials from natural mineral deposits. Such materials usually
were low in nitrogen, phosphoric acid and potash and so were
the mixtures made from them.
Since these early days much progress has been made in de-
veloping new fertilizer materials and in concentrating old ones.
Using more concentrated materials, the average nitrogen, phos-
phoric acid and potash content per 100 pounds of mixed fer-
tilizers has been increased from 13.9 in 1920 to about 21.7 in
1946 or more than 55 per cent. Even more rapid progress is
indicated for the near future.
Low analysis fertilizers cost less per ton but more per pound
of plant food. This is true because it costs no more per ton for
storing, handling, bagging and shipping fertilizers containing
25, 35 or more units of nitrogen, phosphoric acid and potash
than it does for grades carrying less of these plant foods. Of
course the total cost of the raw materials in a high analysis
fertilizer is greater and the cost per ton is higher but the cost
per pound of nitrogen, phosphoric acid and potash delivered
on the farm is less.
Ideas about how much nitrogen, phosphoric acid and potash a
mixed fertilizer should carry vary with different sections of the
country due to differences in soils, crops and climatic conditions.
For example, fertilizers containing around 20 units of these
plant foods are recommended for flue-cured tobacco while grades
carrying 30 or more units often are recommended for other
crops.
Customs and habits play an important part in determining
fertilizer use. In the past, farmers have been slow to develop
enthusiasm for "new" mixtures as replacements for "old"
mixtures that have been used with good results over a period of
years. This has been especially true when the new mixtures cost
considerably more per ton. Also, many of the older fertilizer
distributing machines could not be adjusted for applying the
more concentrated mixtures at the desired rates per acre.
Another reason for the slow acceptance of highly concentrated
fertilizers is the fact that they have not always given good
results, especially when used on the lighter, more sandy and
more highly-acid soils. Unsatisfactory results on such soils




THE LAND .. .AND ITS CARE 41

appear to have been due almost entirely to the fact that the
concentrated mixtures, necessarily made from concentrated
materials, were generally deficient in certain important secon-
dary and minor plant foods and usually were strongly acid-
forming.
Continuous efforts are being made to increase the average
nitrogen, phosphoric acid and potash content of mixed fertilizers
to the maximum consistent with available materials and with the
production of fertilizers having the desired chemical, physical
and plant food qualities A vigorous educational program is
necessary in solving their basic problem.
Extensi\e research has determined the grades of fertilizer best
adapted to particular soil and crop conditions. Use the grades
recommended in your state.

Fertilizer Inspection ond Control
State fertilizer inspection and control laws provide protection
for farmers and also manufacturers.
Thousands of samples of commercial fertilizer are taken an-
nually by state inspectors and sent to the control laboratories
where they are analyzed by state chemists who check the plant
food contents against the guarantees of the manufacturers.
Weights, labeling, registration and other requirements also are
checked by state officials. Thus, protection is afforded both
farmers and manufacturers.
The first practical fertilizer control law was enacted in
Massachusetts in 1873 and today all 48 states have approved
statutes.
All state laws require (1) the registration of brands and
grades of fertilizer; (2) guarantees of the percentages of
nitrogen (N), phosphoric acid (P2O) and potash (K2O) and
(3) penalties for failure to meet the guarantees. Provisions in
some states permit or require guarantees of other recognized
plant foods, establish minimum plant food guarantees and limit
the grades to be sold. The laws are adapted to the specific needs
of the individual states.

Although the variations in soil conditions and crop require-
ments have resulted in wide differences in many state laws, the





SOILS AND FERTILIZERS


advantages of greater uniformity are becoming more evident-
especially in provisions dealing with tags, labelling, grades and
plant food content. Then, too, greater uniformity in control
laws is regarded by many as desirable for better administration.
Close cooperation exists between control officials and the
State agricultural experiment stations in matters dealing with
grades, the agronomic value of fertilizers and enforcement
problems.

Use Fertilizers Efficiently
High yields of quality crops are essential in a successful
farming program.
In many areas fertilizers are the farmer's first line of defense
against low-yield, low-quality, high-cost crop production. The
per acre costs for planting, cultivating and marketing are
virtually the same for crops grown on both good and poor soils,
yet the difference between profit and loss may depend upon
adequate supplies of the right kinds of plant food. High yields
of quality crops are synonymous with low production costs;
poor yields and low quality go hand-in-hand with high cost
production.
Soils vary widely in their natural supplies of available plant
food and many crops have different plant food requirements.
Therefore, many different fertilizer recommendations are made
because experience has shown that no one grade or analysis of
fertilizer is suitable for all crop or soil conditions

FOR THE MOST EFFICIENT AND PROFIABLE iUSE OF
FERTILIZERS .
Follow the fertilizer recommendations of your State Agri-
cultural Experiment Station.
Remember that fertilizers are used to supplement the nat-
ural plant food supplies of the soil and plant food ob-
tained from farm manure and crop residues.
Consider the requirements of the rotation as a whole, as
well as the plant food needs of the particular crop.
Remember that fertilizers do not take the place of lime,
organic matter, good seed, proper cultivation or good
crop rotation.





THE LAND AND ITS CARE 43


Regard good soil structure or tilth as essential in obtaining
the most efficient results from fertilization
Select an analysis containing the plant foods which your
soil ill not supply in adequate quantities to the crop
that is to be grown
Be sure that the plant food elements are in the right pro
portion to lit the needs of your soil and crop rotation.
Use adequate quantities of recommended fertilizers to obtain
profitable yields of high-quality crops.
Apply fertilizer at the right time and use an approved
method of application to obtain the best results with each
crop
Bear in mind that fertilizers can be used most efficiently
when the farmer knows the strong points and the weak
nesses of his soils and can choose the fertilizer grade that
fits his particular needs

Fertilizer Terms

ACID-FORMING-Capable of inreasing the residual acidity
of the sol-1
AMMONIUM NITRATE-Thie amniolium salt of nitric acid.
It has one-half of its nitrogen conte nt in the ammonia form
and one half in the initiate form
AMMONIATING (AMMONIA) SOLUTION-Solution of am-
monium nitrate or of urea in ammonia and water These
solutions contain from 37 to 45% nitrogen.
AMMONIATED-SUPERHPOSPHATE-A product resulting
from the treatment of superphosphate with ammonia solu-
tions or anhydrous ammonia
ANHYDROUS AMMONIA-Dry ammonia gas compressed into
a liquid form It must be stored under pressure

ARTIFICIAL MANURE-A product resulting from the com-
posting of waste straw, corn stalks, vines, leaves, etc with
phosphate, nitrogen-bearing materials and ground limestone
or other hming materials.
AVAILABLE-In a form capable of being assimilated by
growing plants.





SOILS AND FERTILIZERS


BASIC SLAG-A by-product produced in the manufacture of
steel or pig iron by the Thomas process. Phosphoric acid
and lime are chief ingredients of value as a fertilizer.
BONE MEAL (RAW)-A product resulting from the drying
and grinding of animal bones that have not been previously
steamed under pressure.
BONE MEAL (STEAMED)-The product resulting from
grinding animal bones that previously have been steamed
under pressure.
BORAX-A chemical compound, hydrated sodium tetraborate
(Na2B4O7-10 HO0), containing slightly over 11% boron.
BRAND NAME-A specific name applied to an individual
fertilizer.
CASTOR POMACE-The ground residue of the castor bean
remaining after the extraction of oil.
CURING-The conditioning process that takes place when
fertilizer materials are mixed and stored.
CYANAMID-Trade name for a synthetic nitrogen material
containing about 57% calcium cyanamide. It is strongly
basic in reaction.
DOLOMITE-A double carbonate of calcium and magnesium
occurring as a natural mineral.
ELEMENTS-Simple forms of matter which cannot be decom-
posed by ordinary means.
FORMULA-The quantities and grades of materials used in
making a fertilizer mixture.
GRADE-The minimum guarantee of plant food content ex-
pressed in terms of total nitrogen, available phosphoric
acid and soluble potash.
HUMUS-The well decomposed, more or less stable part of the
organic matter of the soil.
HYDRATED LIME-A product resulting from the treatment
of quick lime with water or steam.
LIMING MATERIAL-A material containing calcium, and
sometimes magnesium, in forms capable of neutralizing soil
acidity.





THE LAND AND ITS CARE


MAGNESIA--A term commonly used to refer to magnesium
oxide (MgO).
MANURE SALTS-Potash salts containing a high percentage
of chloride and from 20 to 30% of potash (K2O).
MINOR ELEMENTS-A term usually used in referring to
boron, manganese, copper, zine and iron-ssential plant
food elements.
MURIATE OF POTASII-A potash salt containing not less
than 48% potash (K20) chiefly as chloride.
NITRIFICATION-The process by which nitrates are formed
in the soil.
NITRATE OF SODA (SODIUM NITRATE)-The sodium salt
of nitric acid. It contains 16% nitrate nitrogen.
NON-ACID FORMING-Not capable of increasing the residual
acidity of the soil.
ORGANIC-Containing carbon (other than as carbonates) as
an essential ingredient. This term usually refers to material
derived from plant or animal sources.
PEAT-Partly decayed organic matter of natural occurrence.

PHOSPHATE ROCK A natural rock containing one or more
calcium phosphate minerals of such purity as to permit its
use i the manufacture of commercial products.

SECONDARY ELEMENTS-A term used in referring to
calcium, sulfur and magnesium essential plant food
elements.

SUPERPHOSPHATE
Ordinary (normal or standard)-A product containing 18
to 20% available P205 formed by treating phosphate rock
with sulfuric acid.
Double (triple or treble)-A product containing 43 to 48%
of available PsOa formed by treating phosphate rock with
phosphoric acid

SULFATE OF AMMONIA-The ammonium salt of sulfuric
acid. All the nitrogen is in the ammonia form.





SOILS AND FERTILIZERS


SULFATE OF POTASH-A potash salt containing not less
than 40% of potash (K2O) chiefly as a sulfate and not
more than 2.5% of chlorine.
SULFATE OF POTASH (MAGNESIA)-A double sulfate of
potassium and magnesium containing not less than 22% of
potash (K20), not less than 25% of sulfate of magnesia
and not more than 2.5% of chlorine.
SYNTHETIC MATERIALS-Materials manufactured by syn-
thesis or artificial means. For example, synthetic ammonia
(NH3) is made by combining nitrogen from the air with
hydrogen.
TANKAGE-Garbage tankage is the rendered, dried and ground
products derived from waste food materials.
Nitrogenous (Process) tankage-A product made under
steam pressure from ground inert nitrogenous materials
with or without the use of acids for the purpose of in-
creasing the activity of the nitrogen
TOBACCO STEMS-Products resulting from the grinding of
waste tobacco materials, mostly stems. Usually the nicotine
has been removed
TRANSPLANTING SOLUTIONS--An aqueous solution of
fertilizers applied at the time of setting out plants.
UNIT-A umt of plant food is 20 pounds or one per cent of a
ton of fertilizer.
UREA-A nitrogen compound formed when ammonia and car-
bon dioxide react under pressure with the liberation of
water





THE LAND .. AND ITS CARE


APPROXIMATE CONSUMPTION OF LIMING MATERIALS
ON U. S. FARMS


REGION AND STATE



New England
Maine .
New Hampshire.
Vermont
Massachusetts
Rhode Island
Connecticut

ddle Atlantic .
New York
New Jersey
Pennsylvarna
Delaware
Maryland
West Virginia

South Atlantic
Virginia .
North Carolina,.
South Carolina
Georgia
Florida

East North Central
Ohio.
Indiana
Illinois
Michigan,
Wisconsin

West North Central
Minnesota
Iowa
Missouri
Kansas

South Central
Kentucky
Tennessee
Alabama.
Mississippi
Arkansas .
Louisana
Oklahoma
Texas -

Western .
Washington
Oregon
Callfoirma

United States


1935 1939
ito0 1,x000
tuls ton!B


95 65
5 6
4 2
4 6
46 25
1 2
35 24

375 502
111 122
35 50
187 245
6 9
29 60
7 15

115 278
48 111
45 76
8 42
6 14
9 35

630 1,853
103 176
116 254
140 523
155 135
117 765

266 373
7 13
142 224
105 123
13 13

339 378
175 285
155 70
5 19
2 4




21 30
9 8
3 5
10 16

1,840 3,478


1941 19 4
0 1,000 00
tons tons



262 392
68 90
27 33
42 108
54 75
10 12
61 75

2,240 2,703
694 844
97 186
887 1,099
25 34
129 230
407 3J0

1,532 1,529
913 715


78 177
58 123

6,007 9,701
1,145 1,351
1,001 1,672
2,675 4,217
310 667
876 1,793

2,779 4,726
124 325
1,026 2,500
1,559 1,286
70 616

2,964 3,206
1,626 900
1,166 1,500
84 141
23 275
37 55

19 220
2 63

33 101
6t 29
19 2
9 4 '
S15,81622,35


Pounda Calium-
Magneium Oude
1946 Arplid per Acre
tons
Crop- Cropland &
IN2 IN
442
100 72 5 68.9
57 1230 111 5
87 73 5 68.2
75 123 7 110 2
11 162 9 142.5
112 247.8 214.1

3,325
910 120 0 109 9
196 212,7 190 9
1,448 203 3 187 3
37 100 4 89 4
274 171 8 143.2
460 271 3 228 5

1,801
720 155-3 123 9
483 68 8 64.1
171 34.5 32 9
289 29 3 27 2
139 60 2 48 4

13,157
2,154 187 7 161 4
2,686 229 1 198.4
5,356 249 8 227 0
908 87 6 73 7
2,053 187 3 149 1

7,288
300 14 2 13 3
3,337 149 5 133.8
2,732 193 4 159.9
919 33 4 32 3

3,309
918 142.9 87 4
1,328 184 3 139 4
104 12 9 11 6
235 30 7 27.6
95 13 3 10 8
100 24 4 19 5
425 27 7 24 8
104 3 5 2.9

139
51 74 6 9
31 7 1 6 3
57 72 6

29,462


1Computed on the roloinm baits 50% for agricei.ului lnestone, SS% for blrnlid ljie, 7O% for hydrated limeo, 4% for com
NmreCil narl anid mniaco.lnu material ad 33 % for farln-ug m rl ,
2 Croplnd atr age couiast of cropland hirv eted, crop feature, ide or fiillow land iPasturn acreage coreast of stature land piywed
thin u 1 yIlar 1945 ceSus)
Da trouh il fruom USD Publication No 586. 1915i and 191 from National Ltne Association nd Nation, Crused Stone
Asoclatton






CHAPTER II

General Principles

Physical man is made up of some eighteen of the 96 known
elements composing the material universe. Man's existence is
dependent upon his ability to make the soil yield him a
sustenance
Soils are made up of small particles of different kinds of
minerals mixed with more or less organic matter. All geologists
tell us that these small mineral particles were originally formed
by the breaking down of rocks through glacial erosion, weather-
ing, and decomposition. The mineral kingdom is the basis of
the vegetable and animal kingdoms. Plants and animals are
partly mineral-man is no exception.
So far, science has been able to isolate 96 distinct physical
elements. At least eighteen of these are essential to the growth
of plant life carbon, hydrogen, oxygen, magnesium, iron,
sulphur, calcium, phosphorus, and potassium, are the more
important.
The elements taken entirely from the soil are, calcium, iron,
magnesium, phosphorus, potassium, and sulphur.
Nitrogen is taken chiefly from the soil, but a group of plants
known as legumes-such as clover, peas, beans, vetches, cowpeas,
alfalfas, etc.-gather part of their nitrogen from the atmosphere.
They accomplish this by means of microscopic organisms which
live in small nodules or tubercles found on the roots. Nitrogen
forms four-fifths of the air in volume. In its natural state it is
a gas but by electrical process and by nitrogenous plants it can
be "fixed", solidified
Combinations of the three elements, carbon, hydrogen, and
oxygen, constitute 95% of all plants. They form the fats and
carbohydrates, including the oils and starch. Plants obtain their
supply of these from the air and water. The carbon is derived
from the carbon dioxide gas of the air, and the hydrogen and
oxygen from water, which is itself a combination of hydrogen
and oxygen, absorbed through the roots.
So that only about five per cent of the material of plants
actually comes from the soil. Only minute amounts of mag-
nesium, iron, and sulphur are required and they are present in





GENERAL PRINCIPLES


most soils in abundant quantities. The same is usually true of
calcium, although certain crops, particularly clover, require this
element in considerable amounts. So, by process of elimination,
we find that seven of the eighteen elements essential to plant
growth, need give the farmer but little concern.
The efficiency of soil is measured by its capacity to supply
plants with the several materials and conditions they require
for growth; these include physical support, water, heat, air and
food. These elements of healthy plant environment must exist
in well-balanced proportion and abundance to insure bountiful
yields-even from the best of cultivation and the absence of
disease and insect or animal enemies The vast variety of
climates, soils, and soil conditions determine the kind and loca-
tion of the many varieties of plants.
Generally speaking, the water, heat, and air are furnished
by nature. It also furnishes the food in great measure, but of
recent years a great deal of artificial feeding of plants has
been practiced by farmers. This gives rise to the manufacture
and use of fertihzers.
Nitrogen, phosphorus, and potassium are three elements which
in their various combinations, constitute the vast majority of
the material obtained from the soil by plants. These elements
do not exist in the soil as single elements, but are found com-
bined with other elements, and plants can only appropriate
their foods when they exist in certain combinations, and under
certain physical conditions.
The following mineral elements are also needed by plants in
different degree and proportion Iron, manganese, chlorine,
sulphur, silica, carbon, iodine, bromine, boron and lithium
No chemical analysis of either the soil or the plant will show
dependably and accurately just the combination of ingredients
which should be used. Soil analysis shows the chemical content,
but does not show conclusively the availability of plant foods.
The mechanical condition, which cannot be ascertained by
chemistry, goes farther in determining the fertilizer needed,
than the actual plant food taken up by the growing plant. It is
also true that a crop test is the only absolutely reliable means
of determining the availability of plant food in fertilizers, as
that availability is largely determined by the physical or
mechanical condition of the soil.





SOILS AND FERTILIZERS


The Federal Bureau of Soil Surveys, of Washington, D C.,
has found over 6,600 combinations of soils in the United States.
Florida has a hundred varieties. There is but little information
to be derived from a soil analysis that would be of benefit to
farmers. So much depends on drainage and various physical
conditions that an analysis made under laboratory requirements
is of little value
A chemical analysis may indicate a very fertile soil, rich in
plant food, while the facts are the soils are not productive. This
is instanced by the rich muck lands and river bottoms of the
State, that are fertile chemically, but not productive until
properly drained and sweetened by the use of lime; also, by the
and lands of the west, rich in the elements of plant food, but
not productive until irrigated. Other soils, with less plant food,
but on account of proper physical conditions are exceedingly
productive.
The discovery that the kind and amount of fertilizer which
should be used on a certain sil to insure the best result from a
certain crop can be ascertained only by actual test in growing it,
was a sore disappointment to agronomists and is disconcerting
to the farmer.
There are several methods used in determining the availability
of plant foods in fertilizers; the neutral permanganate method,
and the pepsin hydrochloric acid method are used to determine
the availability of plant foods, and they differ so widely that
65% as shown by the latter is equal to 85% as shown by the
former. The Kjhldahl method is also used to ascertain the
nitrogen content of ingredients making up a compound fertilizer,
but the availability for plant food of the elements contained is
not so easily registered.
All the power of growth possessed by plant life is dependent
upon the presence and availability of the plant foods with which
the rootlets come in contact.
One food cannot take the place of another. No amount of
preparation, seed selection, or cultivation will produce a crop
when the proper plant foods are not in the soil. If two are there
in superabundance, and the third totally absent, the labor is
lost. We fertihze when we apply either ammonia, phosphoric
acid, or potash in an available form. A complete fertilizer
must contain all three, but not necessarily in equal parts The





GENERAL PRINCIPLES


food that is present in least amounts limits the crop Plants
need a "balanced ration" the same as animals
Plant food is drawn in through the tiny, hair-like fibrous
rootlets Each of these fibrous feeders is covered with a thin
skin All the food plants get must pass through this skin The
process is very much ike that of bod-building from digested
food in the stomach and alimentary canal of animals-including
human beings. The villi of the digestive tract are analogous to
the root fibers that take up the soil water which holds in solution
the dissolved plant food elements The fuzz on the roots has no
perceptible openings though which the finest powdered dust
could get Plant food which will dissolve so as to go with the
water through the skin of these tiny roots is called soluble and
is therefore available for plant nourishment. The plant food
thus drawn in by the fibious rootlets passes up through the
roots, the trunk, stalk or stem, then the branches and out into the
leaves or blades where most of the water is evaporated, tran-
spired, or breathed off into the air A process of exchange, of
transpiring, and absorption takes place in foliage--much like
the process which takes place in the lungs of animals that
breathe out carbonic acid gas and take in oxygen The sap of
plants is elaborated in the foliage by this exchange of moisture
drawn up from the ground, and the taking in of gases from the
air. After this "elaboration," the sap flows back to build up
the plant and its fruit-just as blood flows back from the lungs,
where it is surcharged with oxygen, to the heart and thence
through the arteries to the capillaries in all parts of the body
where assimilation or body building takes place.
Plants exposed to light develop chlorophyl, which is the
coloring matter that gives the shades to certain portions of the
protoplasm The function of chlorophyl consists of the absorp-
tion of carbon dioxide gas, resulting in the transformation of
oxygen and the formation of new organic substance
A plant food is much more available when locked up in some
medium than in others Certain sources of nitrogen yield it up
to the action of soil moisture more readily than others This
makes the source of nitrogen, phosphorus, or potash of im-
portance to the farmer, who may want either rapid or gradual
solubility to suit a quick, or slow-growing crop.
Justice Von Liebig was the founder of Agrieultural Chemistry.
It was he who discovered that plants feed on soil chemicals,





SOILS AND FERTILIZERS


and if these are not in the soils in form available for the growing
plant to appropriate there can be no growth and no yield of
harvest. He demonstrated how crops depleted the soil, and how
worn out soils could be restored to fertility by the application
of artificial fertilizers.
He announced his discovery in 1840.
Next to the knowledge of plant breeding the knowledge of
plant feeding has had the most important bearing on modern
agriculture. When we think of the magnitude of the commercial
fertilizer business throughout the world it is indeed remarkable
that the knowledge of the chemistry of the soils came to our
service at so recent a date. If the ancients had possessed this
knowledge history might have been different.
No iron-clad formula for commercial fertilizer can be made
to suit all soils. The available plant food in the soil and the
amounts of each of the ingredients of a mixed fertilizer that a
given crop draws from the soil per acre is the basis for deter-
mining the formula for the crop
The availability of plant food in soil, the chemists tell us,
cannot be determined in the chemical laboratory. Some chemists
tell us that it is impossible to ascertain accurately the avail-
ability of plant foods in commercial fertilizer. The law of
Florida requires that the tag state the per cent of total ammonia,
organic ammonia and inorganic ammonia, the available phos-
phoric acid, insoluble phosphoric acid and water soluble potash,
and the sources from which these elements were obtained.
Chlorine not more than_ moisture not more than........, but it
does not require that the tag state the relative percentage derived
from each source, because of the contention of chemists that it
is impossible to ascertain with certainty the sources from which
these elements are obtained.
There are three forms of nitrogen in soils, and should be in
well-balanced fertilizers-organic, ammoniacal and nitric. The
last named is soluble and immediately available for plants. Am-
moniaeal nitrogen is converted into nitric form by the action of
bacteria and soil chemicals in rather a short period. Organic
nitrogen takes somewhat longer, due to its process of being
changed to the ammoniacal form before the plants take it up.
Plants get their carbon from the air by way of their foliage and
this combines with the oxygen in the water taken up by the
roots to form carbonic acid, which in turn, desolves compounds





GENERAL PRINCIPLES 53

supplied by the soil solution. The hydrogen in the water com-
bines with nitrogen to form ammonia, and this combination de-
pends very largely on the warmth and depth and texture of the
soil as well as on the action of favorable bacteria. The amount of
moisture in the soil goes a great way toward determining the
amount of bacteria. The tilth-depth of tillage or amount of soil
available for plant root--of soil is as much a determining factor
as the mere presence of plant food elements. Oftentime the
farmer will use barnyard manure in connection with commercial
fertilizer, in which ease it is an indeterminate equation as to
what is the best formula to be used. The kind, quantity and
quality of the manure would have to be known before the
formula and quantity of commercial fertilizer needed could be
determined.
Higher Analysis Fertilizers
Generally speaking, the getting away from lower analysis
fertilizers to the higher analysis ones is quite a saving to the
farmer. Some states have enacted laws fixing a minimum
standard for total available plant food in mixed fertilizers.
Florida's standard is fourteen per cent minimum for all mixed
fertilizers. The value of a ton of fertilizer lies wholly in the
number of units of plant food it contains together with the
small amount of the rarer elements which it may also carry,
that are necessary to plant growth.
The higher the anal sis of the fertilizer, the more economical
it is to the farmer. For instance, a fertilizer containing 20 per
cent total available plant food can be had, which is made from
materials equally as good as one containing 14% total available
plant food. There are six more units of plant food for the same
freight; a very small amount more profit to dealer, and the
same labor of handling. A twenty-eight per cent goods has an
even greater saving. However, higher analysis goods naturally
contain less of the rarer elements necessary to plant growth.
There are now appearing synthetic fertilizers, on the market,
in large quantities. These will run from twenty-five to sixty
and even sixty-five per cent total available plant food. They are
concentrated chemicals and carry nitrogen, available phosphoric
acid and potash. They do not carry much of the other mineral
elements; such as iron, manganese, iodine, bromine, boron,
lithium, copper and magnesium; needed in small amounts for
most plant life. Cover crop and organic fertilizer will go far
toward rectifying this deficiency.






CHAPTER III

Sources and Functions of Fertilizer Elements

Pure nitrogen is a gas that has no smell, color or taste. There
is plenty of it in the air, but leguminous plants are the only
ones that can extract it from the air and store it in the soil.
Modern science enables man to take it out of the air by power
process. Ammonia is a compound of fourteen parts of nitrogen,
by weight, combined with three parts by weight of hydrogen.
The Federal Government has a large plant for extracting nitro-
gen from the air, located at Sheffield, Alabama.
It is difficult to secure an adequate supply of nitrogen. It is
found in combination with other materials but these materials
are scarce and high. Nitrogen-bearing materials are called
nitrogenous or ammoniates. It is often confusing to laymen to
use the words "nitrogen" and "ammonia" as synonymous, and
yet speak of them as being different elements. This is because
ammonia by weight is fourteen parts nitrogen to three parts
hydrogen.

The common sources of commercial nitrogen are:
Nltr*en EalTvlnlt to *immal
Nitrate of Soda 15 to 16 18 to 191/2
Nitrate of Ammonia., 19 to 22 23 to 26
Dried Blood 10 to 14 12 to 17
Tankage 5 to 9 6 to 11
Fish Scrap 7 to 8 81/ to 9%/
Cottonseed M ... ... 61 to 71 7 to 9
Castor Pomace 5 to 6 6 to 7
Nitrate of Lime.
Horn and Hoof 31.
Hair and Wool.
Leather Scrap.
Peat.
Tobacco Stems.
Air.

Its Function
Protoplasm is the physical basis of life and nitrogen is neces-
sary for its production. The effect of nitrogen on plants is to





FERTILIZER ELEMENTS 55


build up the body, gi e rich, green color to leaf, and rigorous
growth.
Too little stunts growth, and too much gives rank growth
with snappy, weak stalks, and delays ripening Large amounts
suit plants like celery, lettuce, etc., where crisp, tender stems
and leaves are wanted. For immediate results it is best to use
nitrate of soda. while for seasonal growth other forms can be
used. The activity as well as aa ailability of nitrogen in materials
like leather scrap, hair, or peat, is but one-fifth as much as that
in nitrate of soda
No organic cell can exist without it has nitrogen in combina-
tion with carbon, hydrogen, oxygen and sulphur. Plants are
nourished by the nitrogenous substances contained in the soil
and water, and animals by the nitrogenous substances in plants
and other animals However, neither plants nor animals can
utilize nitrogen unless it is fixed (non-volatile) in some com-
bination.
The world's principal source of nitrogenous material in a
commercial sense has been the nitrate beds of Chile The United
States consumed during the year 1913-taken as a normal rate
-140.000 tons of inorganic nitrogen, equivalent to 658,000 tons
of ammonium sulphate, of which about two-thirds was Chilean
nitrate This material in the raw state is blasted from the
pampas of Chile This valley was once part of the bed of the
ocean in winch floated vast meadows of sea-grass A volcanic
upheaval formed what is now the mountain range rising sharply
from the Chilean seaboard and created a lake between that
range and the Andes, forty-five miles inland. The sea water
evaporated, the sea-grass decomposed and hardened into a
mineral soil imprisoning the nitrogen which the sea-grass had
drawn ages before from the air. The large lumps are crushed and
boiled, the first step in concentrating into exportable form the
nitrate of soda After the caliche is removed from the pampas
it is carried in open freight ears to the crushing house and
reduced lo a form which renders it the more readily soluble in
the boilers, to which the broken caliehe is borne by an inclined
conveyor belt. In the large steel pans of the nitrate plant,
exposed to the Chilean sunlight the liquid product of the boiling
vats finally yields in crystals the nitrate of soda of commerce.
After the mother liquor is drawn off and relieved of iodine-
one of the by-products of the industry-and returned again to





SOILS AND FERTILIZERS


the boiling vats, the nitrate of soda is left to dry and is finally
conveyed in open cars on high trestles to be dumped into the
loading platforms.
The air over every acre of the world's surface contains ap-
proximately 35,000 tons (not pounds) of nitrogen. This state-
ment about the wealth in the air will surprise many farmers
in the United States-and will in other countries, too, for it
appears in informational material prepared by fertilizer special-
ists of the U. S. Department of Agriculture for circulation by the
Food and Agriculture Organization. Every farmer has this
vast free supply on which he can draw. At current rates for
nitrogen fertilizers this reserve nitrogen over every acre would
be worth approximately $8,000,000 (millions, not thousands).
The difficulty in capitalizing on this wealth lies in getting it
down to earth and into the earth where it will nourish crops.
The only practical way for an individual farmer to draw directly
on this reserve supply of nitrogen is to plant legumes and so go
into partnership with the nitrogen-fixing bacteria that grow m
association with legumes and thus make immediate use of this
nitrogen reserve in the air. This is not a rapid way of collecting,
but is a way that farm scientists and practical farmers agree in
recommending.
The fertilizer specialists also point out that the air, the land,
and the waters of the earth are the sources of the three principal
fertilizing elements that farmers must have to keep their crops
growing. And each of these subdivisions is a principal source of
one of the three elements.
The atmosphere (air) is the principal source of nitrogen.
The lithosphere (land) supplies practically all the phosphorus.
The hydrosphere (water) is an important source of potassium.
From the land, also, the fertilizer industry gets considerable
quantities of both nitrogen and potassium.

Atmospheric Nitrogen
Four-fifths of the world's nitrogen is contained in the air.
Only one-fifth is present in the soil, animal and vegetable
matter. Nitrogen in its elemental form constitutes about four-
fifths by volume or three-fourths by weight of the atmosphere.
The atmosphere covers the earth some fifty miles in depth, and





FERTILIZER ELEMENTS


above every square rnile ot the earth's surface there is estimated
to be about 21,683,200 tons of nitrogen, wl)ile the total area
of the earth s surface approxiinates 200.000,000 square miles.
The conversion of the uiltrogen or tih air into compounds
available for use ilax I1, accormplisheid iTl a number of ways,
among which are the following.
1. The direct oxidation of nitrogen and its coinersion into
nitric acid.
2. Toio co(lbilnation0 of nitrogeit with metals lo form nitriiles,
wich10I may be treated to furinish atimmonia,
3 The formation of cyanides or eyanoeen compounds by the
eombnlination or nitrogen "itlh metals and carbonl
4. T1l' IOliiiation11 of a colipolll) i li til 'lrbid, producing
c(aiiatilid
5 Thie diret (.Ollibiliat.lli of nililogPll alld hydrogen nitrites
aLKnd nitiateS. w noli ,I'y be ilt In addition to being,' i essntial to life, nitrogen is the chief
and most uslc ele'meil in explosives Dminig fli World War
whien the United Slates found itself in need of nitrogen for the
]nllnllfactnc of lln pom'der and other explosives the eyvainillid
and Ilabor proceesse- the last two mentioned above--were
recommnenldd 1V scientists appolilnt to investigated the fixation
processes As it ie -lt, the Go(iinlll(tll built two plants, one at
Muscle Shoals aniid one at Sheffield, Alabama. utilizing thel falls
of the Tennlessee Mlier to furnishl the po.er. Plant nunlber one
was colllpeted, bint neve cllae inill active use until Tlh Ainr-
istice This plant as disignned to produce 60,000 pounds of
anhydrous ulnmnoia pIe d(aiv. Plant number t o for the pro-
duction of cyanamild was icolpleled, but operation was amspendled
pending the deeisionI as to the finll disposition of the plant. It
was designed to produce 110,000 tons per annumll of anmmonium
nitrate
Under stress of liar, plants were built with an a annual capacity
of some 50.000 tons of fixed nitrogen. In 1917 by-product coke
ovens produlled 80,000 tons of nitrogen or about 400,000 tons
of ammonllium sulphate
Our grain crops, potatoes and cotton of th United Slates
require 6,372.000,000 pounds of nitrogen. Of this amount not





SOILS AND FERTILIZERS


more than 2,000,000 tons are returned by leguminous crops,
imported nitrates, coke ovens and farm manure.
If water power can be harnessed to plants that will produce
commercial nitrogen at a much lower cost than by the old
processes and in unlimited quantities to neglect to proceed with
this work by the government or to lease it to companies under
proper contracts guarding the rights of the public is beyond
excuse. Public opinion should so function as to impel a policy
for the public welfare.
At the time of World War I the cyanamid process had become
fully developed, while the synthetic ammonia process was still
in the development stages. During the war several large cyan-
amid plants were built both in America and abroad. But none
have been built since the war. On the other hand, practically
all of the enormous European expansion of the nitrogen fertilizer
industry has been through the building of new or the enlarge-
ment of old synthetic ammonia plants, until today these plants
far outnumber the cyanamid plants and their output of fertilizer
is more than four times as great. The amount of nitrogen fixed
by the cyanamid process reached a peak in 1917, but in 1918 it
was passed by the synthetic ammonia process. At the close of
the war there were only two or three of the synthetic ammonia
plants in existence, but today there are 35 or more. The world's
production figures by the two processes are significant of the
trend in this matter.

Phosphoric Acid
Phosphoric acid is a compound which contains 43.7% phos-
phorus by weight. Nature does not isolate phosphorus; it is
always combined with something else-usually lime. The prin-
eipal commercial sources are phosphate rock, acid phosphate,
bone, and Thomas slag.
In ground phosphate rock, or floats, and bone black, the
phosphoric acid is insoluble and therefore produces effects very
slowly. These may be used for composts where immediate
effects are not needed. Raw phosphates and bone black are
treated with sulphuric acid, rendering them soluble, and thus
producing acid phosphate. When rendered available it is of
equal value, no matter from what source obtained. Splendid
results have been secured by the use of soft phosphate when





FERTILIZER ELEMENTS


used i1 sufficient quantities and properly composed or thor
roughly inoculated.
It takes 50,000 pounds of water to dssolhe one pound of
insoluble phosphoric acid Of course, this means that "insoluble"
does not mean that ,nleh is incapable of being dissolved, but
that it is in combination of two parts of phosphoric acid with
three parts of ime. Tins form is found in raw phosphate rock
and in bones. The phosphorus found in bones is of greater value
than that found in rock, for the reason that bone is organic and
decays when put into the ground, where it rots through the work
of bacteria Rock phosphol e acid is of no value until it has
been dissolved into soil monstue. Even grinding it to powder
won't help much, as it must be in such solution as to pass
through the skin of the fiber rootlets The rock must be treated
with sulphuric acid. which changes two of the three parts of
lime into gypsum oi land plaster- sulphate of lime-these two
parts kill the acid an d leave the phosphoric acid combined with
only one part of lime- and the product is acid phosphate or
superphosphate Methods so far used in extracting the phosphate
rock from the soil and mi preparing it for fertilizer have been
very wasteful, as commercial acid phosphate made from 32 per
cent lock contains only 16 per cent of phosphoric acid. The
elaborate washing and sel eelling process now used in preparing
the rock for treatment with acid often results in a loss of more
than half the material. A new process recently discovered
promises to saxe this waste
The coumbiation of both water soluble and reverted phos-
phonc acid is the form in commercial fertilizer It 1i a combina-
tion of two parts of phosphoric acid and one part of hime After
soluble phospholic aeidl has been in the soil for a time it under-
goes another change-tihe lime uniting with the phosphorus be-
comes revertedd,' which results in a combination of two parts
phosphoric acid with two parts of lime. In this reverted form the
phosphoric acid is held in the soil, and becomes slowly available
In making phosphorie acid the first thing necessary is to
operate an acid plant. Sulphur ore is mostly imported from
Spain. This ore is burned in furnaces. the fumes being con-
densed in immensee lead chambers. Some nitrate of soda is used
in the process. The acid produced is transferred to an acidulat-
ing plant.


59





SOILS AND FERTILIZERS


Finely ground phosphate rock-pulverized to a fineness of
about 100 per cent through a 60 mesh screen, mixed in equal
parts with sulphuric acid at 520 (Baume)-the mixing is done
in flat circular pans provided with heavy stirrers which give
a thorough mixing of the rock and acid From these pans the
mixture, which is still liquid, is dropped into closed dens and
left about twelve hours, long enough to solidify and for chemical
action to render the phosphoric acid available. It is then trans-
ferred to the mixing plant. Acid phosphate is valuable for the
percentage of phosphoric acid which it contains and is usually
sold on a unit basis

Many fertilizer manufacturers are nothing more than mixers
of the fertilizer ingredients, which they buy from plants that
manufacture the separate elements They buy the constituents
at wholesale and mix according to the various formulas and give
the product a brand name, advertising and placing on the
market commercially. The various materials for a complete
fertilizer are assembled, analyzed and run through mechanical
mixers in the proportion that is desired These mixtures are then
laid away to cure in large piles-each analysis to itself. When
the shipping season opens these cured piles are again run
through pulverizing and mixing machinery, put into bags and
cars and dehvered to fill orders.

Materials Furnishing Phosphoric Acid
MATERIAL TOTAL AVAILABLE INSOLUBLE
Acid Phosphate 16 to 17 15 to 17 1 to 2
Dissolved Bone Black 17 to 19 15 to 18 1 to 2
Bone Meal 20 to 25 5 to 8 15 to 17
Dissolved Bone 15 to 17 13 to 15 2 to 3
Peruvian Guano 12 to 15 7 to 8 5 to 8
Thomas Slag 22 to 24 22 to 24
Superphosphate 18%
Triple Superphosphate 44%

In experiments Thomas slag, when finely ground, is found to
furnish a degree of food for growing plants-although chemical
tests do not indicate it. Bone meal is very similar, but breaks
down under bacterial action.





FERTILIZER ELEMENTS


Functions of Phosphorus
Phosphorus is necessary for the development of strav, seed,
and good loot systems. It eives stabdilit and vigor to plants,
builds liber. hardens and matures growth, and is a ripening
element ft is conducive to favorable and beneficial soil bacteria

Potash
Potassilum i oine of the elenleiint The Latin name is kallum,
which is the explanation of wsh K sXtands for potassium in
chemistry The oxide of potassium is a compound of 78 parts
bi eight of potassium combined ith sixteen parts by weight
of oxygen. The chenlist imbolle fornmul is K2O, sulphate of
potash KaSO(, muritate of potash KCL. sulphate of magnesia
MgSO4, chloride of magnesia hMgCis, chloride of sodium NaCI,
sulphate of lime Ca(Soi, does not contain potash

The natural products yielding potash are:
Ka init. calculated to pure potash KO2 12.8
Carnality, calculated to pure potash K2O .. 9 0
Sl hinit, calculated to pure potash K!O 124

The great deposits of potash at Sassrutt, Germany. were dis-
covered in 1847, and the phosphate rock of South Carolina in
1868, and later in Plorida, Tennessee. U'tah Wyoming. Mon
tana, Kentucky, Arkansas and Virginia. It was not till after
the Franco Prussian War that extensive demonstrations of the
value ef phosphate and potash were carried on Germany had
potash and no phosphate. Ameriea had phosphate and no potash
The Germans were exhausting the available phosphorus in the
soils, and v e were using up the available potash in our soils,
by an unbalanced system of plant feeding

The discovery of the Thomas basic slag processes of making
steels from phosphatic iron ore greatly supplemented the Ger-
man fertilizer needs, but it did not help America's need for
potash. The Germans made the most of this wonderful monopoly.
The writer visited one of their largest mines in 1913. It is a
wonderful bed of crude rock salts. The mining is easy and
simple, as no extraneous matter has to be removed. As it is
tunneled there is no overburden to remove and there is no seep-
age of water to interfere.





SOILS AND FERTILIZERS


The "raw deals" so often handed American dealers provoked
extensive explorations to discover deposits, and experiments to
discover means of manufacting it from other materials con-
taining this element. The lakes of California, Utah, and Ne-
braska were found to contain an abundance of potash and cer-
tain shales were found to be workable for potash; the waste
of blast furnaces, beet-sugar mills, molasses distilleries, wool-
washing plants and cement works. The cost of manufacturing
thus far has been too high to compete with the German products
-about $125.00 per ton.
During 1919 California had twelve plants and turned out
33,879 short tons; Nebraska, 10 plants, with 34.142 tons out-
put; Utah, five plants, and 33,858 tons.
Pure potassium has peculiarities that prevent its use as a
plant food. It must be combined with other elements before
being suitable for fertilizer. Two parts potassium with one of
sulphur and four of oxygen is one combination Sulphate of
potash K2SO4, potassium and chlorine, fifty-fifty, is another
which makes muriate of potash-symbol KCI. A third combi-
nation is two combining weights of potassium, with one of car-
bon and three of oxygen- carbonate of potash KCOs A fourth
combination is one each of potassium and nitrogen and three of
oxygen. This is nitrate of potash, symbol of KNOs.
Potash is essential for the production of starch, fiber and
the full development of plant and seed.

Bacteria
Bacteria play so important a part in fertility of soil that
they hold an important place in the discussion of fertilizers
Bacteria are microscopic organisms, microbes, fungi, or para-
sites. An organism is either an animal or plant having organs
performing special functions.
By far the greater percentage of bacteria is vegetable, both
in soil and in animal organisms. but vegetable bacteria have
no chlorophyl. The bacteria that thrives in the human organism
may be beneficial-as in theprocess of digestion-or injurious
-as in case of the various disease-producing germs.
Bacteria live in soil They cannot thrive where there is no
humus. There are many kinds, and each kind has its special
substances on which it thrives best. A group known as ammoni-





FERTILIZER ELEMENTS 63

lii', begi'is to al'ow aIs ,son as placed in moist soil. It lives
hlu a '-olil linl', an ni the protein whlii has been absorbed is
v chage inlo t iinmonLia. When this glullp dies other groups
Inke up Ilhc anliunnial, and change it into nitrite. When it dies,
tnllthlr .l-roup akes ip this ntrite amn cLhanges it into nitrate.
T nI, l;il piroiict is realili soluble aiili is dliOolved into soil
noi'l rl. The rootlets then take it iII along with the soil
moist i',. Most organic and some inorganic fertilizers must be
l hanged bi these bacteria bel'ore the plant foods become avail-
able. Thle p need wxiarith, nmoi'ture, nhumIus, and air; too much
Water eclulles the ilr and too imllh avid hinders their growth.
Different kinl, of laetri.a aire needed to dissolve different
kilnd, of matel-il. I in tie soil Good results have been secured
in Mll u -oil, thronlgi tile ii'e of phospho-germs housed in humus,
but w ith i1nI ,[lI ii of pll it [oodl oit nCt. By housing numerous
kinls tli blct(riil i i a suitablie idllliil, various materials, con-
taininti plant food cleiienlll are released by their action, which
would nt be affected by oil, one kind of bacteria.
,Departments of Agriculture are often asked to give opinion
ais ti the alue oi adiertisci soil bacteria. It is manifestly im-
possible to pass, jludginlm on these bacterial inoculents, the
value of alich depemin upon the number of %irile organisms,
adapt l to the .oil it, ihich they are to le applied, whose mis-
sion i, tol ltraiinfolrm thli oinganii and uinelral elements in the
soil o as to rondrI tihem ava ilable flo t he plants to be grown.
It is als I\ideltni that tlns kind of soil building agency must
be judged Ih an entirely different standardd from that of fer-
tililer-. No ciheicai test would reveal anything as to the value
of thele e baailiri. 1'l ai reiuliatl ting the manulfacture and sale
of oilnnrel tail fl'orililers do not touch the subject of soil inocu-
lints. Thi, phase itf palieal soil improvement has not been
redu'd to an linctptd scienee. When unbiased investigation
and adequate denI nst ritioll fix a staulard for soil inoculation
value tlere should ibe legal regulation of the sale of soil bac-
ti'i lth samne as lor conlmercial fertilizers.
St fat;r l attleiiiptis hal boen made to supply carbon in avail-
able ormll TIo plnidts. an element that constitutes an average of
40', o tllh str lturatl arts of plants. During the carboniferous
age, ;lohn the atmosphere was surcharged with carbon dioxide,
egitlation grew so plcnteously and of such gigantic size as to
prepare the material for tihe great coal beds of the world. Prof.
Hiede] las deimonstiated that artificially supplied carbon di-





SOILS AND FERTILIZERS


oxide will produce remarkable results in the growth of plants.
No scheme for commercializing this discovery has been at-
tempted. Organic material operated on by bacteria may liberate
carbon dioxide which passing up through the soil is absorbed
by the leaves. No less an authority on foods than Alfred W.
McCann maintains that the ash of foods, which is usually
passed over as so much unavoidable rubbish, contains chemicals
which are absolutely essential; that the mysterious vitamins
are but the sum total of certain mineral elements in food; and
their marvelous effects but the resultant of the chemical reac-
tions set up by these mineral elements. May it not be that the
carbon of plants and the ash of foods have not received con-
sideration commensurate with their importance ?

Humus
Burzellus classes all organic matter in the soil as humus.
IIumns is formed by the decay of vegetable matter-vegetable
mold.
IIumus is a generic term applied to a group of substances,
which form the organic matter of the soil.
They range in color from a brownish yellow to a blackish
brown, or black, and are non-volatile. They are probably all
composed of carbon, hydrogen, and oxygen.
While Mulder regarded humus as the almost exclusive source
of the organic constituents of plants, Liebig, and other chemists
of today, regard the atmosphere as capable of affording an
abundant supply of all these substances. The atmosphere con-
sists of nitrogen and oxygen gases, vapor, carbonic and nitric
acids, and ammonia Plants can appropriate these from the air
only b. the roots or foliage Leguminous plants extract nitro-
gen from the air by way of the roots through bacterial action
in the nodules on the roots. The air comes in contact with the
rools by the soil being porus, which is aided by cultivation.
Some soils are closer than others, and some growths have a
tendency to impact the surface with turf-Belmnuda grabs, as
an example--while other plants have a loosening effect--as
the cocklebur.
Humus performs a useful function in retaining moisture,
furnishing a habitat for bacteria, and in holding potash, soda,
lime. and magnesia, and in preventing them from being washed
out of the soil.





FERTTLTZER, ELEMENTS


COMPOSITION


MATERIALS


Acid Phosphate
I i Rock
Steamed Bone Meal
Raw Bone Meal
Dried Blood (high grade)
Tankage (concentrated)
Cottonseed Meal
Cottonseed
Fish Scrap
Nitrate of Soda
Sulphate of Ammonia
Cyanamid
Kamit ..
Potassium Chloride (muriate)
Potassum Sulpha8te
Manine Salt


OF FERTILIZER MATERIALS

Percent or Pounds in 100

Phosphorie ,
Nitrogern Pharid Potash

13 to 16
16 to 20
26 to 32
2 to 3 20 to 25
3 to 4 21 to 25
12 to 14
10 to 12 2 to 3
Sto 6 2 5to 28 1 8
32 18 12
8 to 10 6 o 9


PERCENTAGE OF PLANT FOOD CONSTITUENTS IN FRESH
ANIMAL EXCREMENTS


Iorse


Exrrement


Portion





Liquid
Mixed

Solid
Liquid
Mixed

Solid
Liquid
Mixed

Mixed





66 SOILS AND FERTILIZERS

COMPOSITION OF DRIED OR WATER-FREE EXCREMENTS





CHAPTER IV


Home Mixing

If tle farmer would adopt and practice home mixing of
fertilizer it would save million of dollars to the producers of
the country. Not that fertilizer mixers make exorbitant profits,
but they must charge enough to cover their enormous overhead
expenses, to which mnst be added the freight on the dirt used
as a filler It is good business, economical, educational, and a
mark of individually, to buy your own ingredients, and do
iour own (ompoundiin The elements composing complete fer-
ti/er (an be puiehased separately They should be bought by
communilmet in bulk, and handled on a cash basis if possible.
The lea'ons why the majority of farmers buy complete fer-
tilirze ale i ) the a.ie witi which it can be bought on time;
(b) the desire TO shun The work of buying separately the dif
feoent elements and mixing them; (e) the lack of self confidence.
The following articles constitute a fairly good equipment for
home-mixing fertilizer
1-A screen uih 3 meshes to the inch, 5 ft. long and 2 ft.
Ride.
2-A sho\el with square point.
3-An iron rake
4-A pair of large scales
,-A tight barn floor, or hard, dry, smooth ground.
6-A heavy wooden pestle for crushing big lumps of the
material.
The seieeinug should be done first-all lumps crushed and
screened again Then spread out the most bulky of the element
in layers-one on another-beginning with the most bulky con-
stituent. Shovel the heap several times, until no streaks appear.
Then sack or box and keep in dry place until ready to use.
There are compatible and incompatible elements. Just as a
ph>lician who knows nothing of chemistry or pharmacy might
wlite a prescription that could not be compounded because of
incompatibility of certain chemicals included, so, in mixing the
constituents of a complete fertilizer, it is necessary to know the
action of the different ingredients upon each other. To mix
potash salts with Thomas slag is likely to result in hardening,





68 SOILS AND FERTILIZERS

and render it necessary to crush and pulverize before Iuing.
Certain ammoniates contain iron, and if mixed with acid phos
phate will lose a considerable portion of its available phosphoric
acid Sulphate of ammonia should not be mixed with Thomas
slag and Norwegian nitrate Cyanamid should not be mixed
directly with sulphate of ammonia, but should be mixed as per
dnections. Basic slag should not be mixed with sulphate of
ammonia, blood, or tankage, as the lime affects these materials
and releases ammonia. Lime should not be mixed with ngano
as it causes nitrogen to escape. Sulphate of ammonia should not
be mixed with basic slag nor quicklime with acid phosphate To
mix lime with superphosphate renders the phosphoric acid less
soluble-therefore, less valuable.







CHAPTER V

Fertilizer Formulas

The following table show, how to find the quantity of each
material niecesisaiy to make 1,000 pollnds of feitilizer of any
desired analysis


valuablee Available Phosphoric Acid Available
Percentage Nit ogen Potash flom
RfeqLured fnm Ntrate Florn 14% From 16% Sulphate
of Soda \Cid 'i 6 of Potash
Phosphate Phosphate

1% 67 lhs 71 bll. 63 Ibs 19 lbs
2% 133 b-. 143 1b 25bs 2 s b 38I lbs
3% 20!0 li- 214 I1 188 Ib. 58 lbs.
4% 267 lbs 286 ibs 250 Ibs. 77 lls
3% 333 lbs 3i7 ibb 313 lbs 96 lbs
6% 100 lbs 429 lb,. 375 lbs, 115 Ibs
7% 467 lbs 500 lbs 438 Ibs. 13 lb
8% 533 lbs 571 lbs 500 lbs 154 lbs.
9% 600 lb, 643 Ib, 563 lbs. 173 lbs
10% 667 lbs 714 Ibs. 625 lbs 192 lbs


If a fo ulh 4-t 7 is wanted, it MOildl mean 267 pounds of
nitrogeni, 500 pounds ot 1'i phosphate, and 96 pounds of sul-
phate of pta mak total.aking of 863 pounds, vwich contains
the same animouit to plant iood as 1 000 pounds of 4-7 5 com-
plete, rea(d- niud, cmnmierenia fletilier To make out 1,000
pounds add dry loam as "filler."
A B Ross hls slio n that nicither in the Pennsyhania nor
Ohio long-tuinc expelimens did niitlogen prove profitable in
fertill7ls for rotaticins containing clover. Those xperiniments
showed that plallts got nitrogen from elsewhere than leginnes
o0 fromI eonlllllerelill ililZels, as the amounts taken roll the
soils exceeded tlie llmoiunt stored by the legumes and lihe alnolunt
conlainedl in the applied fertilizer

Legume baeteria tile not tlie only soll organisms that can
inm;a direct use cf nitrogen from the air A group known as
the a/otobacter have this poier Perhaps there arc others This
IN ]Ientiolled ai a sQgcbtio tio t those who may get results which
dilfer from what they had a right to expect fromi regular
methods.





70 SOILS AND FERTILIZERS

What we all like is a "cut-and-dried" formula for doing
things, and we do not like the formulas to disappoint us when
being put to the test. But in the use of any formula herewith
given, it should be borne in mind that much depends upon the
mechanical condition of the soil, the elements of available plant
food already in the soil, and other contingencies, as to the
result that will follow.

Potatoes- (Irish)
If you use complete fertilizer you might have a formula
like this:
Nitrogen ..-............. -- ...................-...-....... 4%
Available phosphori acid............................... 6%
P otash ........ .... ....... .... ..... ....................... .. ...---- -...... 8%
A m m onia .......................................... ... ................................. 5%
Phosphoric acid .................. ........ ............... .... .... ...... 86%
Potash ..... ................. .. .. ............... ....-.. ....... 5%
N nitrogen ... ...................... ............ ............ 5%
P hosphoric acid ........................................... ...... ........... 7%
P otash ........ ......... ... ........... ......................................... 8 %
And use from 1,000 to 1,500 pounds per acre. Or if you do
your own mixing, the formula might be:
N itrate of soda ....................................................................... 320
A cid phosphate ................ ..................... .. ... ............ 100
Sulphate of potash ............................................. 100
Dry loam ..............- -.................-....... 100
Stated in percentages:
Available nitrogen .................... ...................... 4.8
Available phosphoric acid ....................................... 7.68
Available potash ......................................... ....... 5.0
This is taking the 1,000-pound basis. It will need a thousand
pounds to the acre, but 800 additional pounds of loam should
be added to secure a satisfactory mechanical condition for the
fertilizer.

Pottoes- t(Sweet)
A m m onia ..... ................ ......... ............. ......... 4%
Available phosphoric acid ..... ............................. 6%
Available potash ...... ................................... 8%





FERTILIZER FORMULAS 71

Six to eight hundred pounds per acre, apphed at time of
plani ng.
Other formulas widely used are:
Nitrogen ..... 89 pounds
Phosphoric acd ... ........... 23 pounds
Potash ... ..... ......... .................... 102 pounds
Nitrogen ....... .. .. ....... .. 8%
Phosphoric acid .... 2%
Potash ..... ... ..... ... 10%

Tobacco
Available nitrogen ...................... .......... 5
Available phosphol acid ..... .... 4.... .%...... 4
Available potash .. ..- 8%
Nitrogen .... .. 3%
Phosphoric acid . ... .......................... ................... 8%
Potash -. .. ....... 3%
Nitrogen .. 4%
Phosphoric acid .. ........ 5%
Potash .............. . ..... ................ .. 9%
Kainit or runi arte of potasih should be avoided, as the chlo
rine militates against burning ellI in ceaits. The sulphate form
is preferred Per acre, fioai 1,000 to 1,500 pounds, preferably
given in three equal dressings, just before planting and at
time of first hoeinug and, last, from tao to three weeks later.

Corn
Fifty bushels of corn per acre takes front the soil 67 pounds
of nitrogen. 31 of phosphoric acid, and 80 pounds of potash:
Judged b\ these requirements, if the land is equally deficient
in the three constituents of a complete fertilizer the formula
should be:
Nitrogen ........ 6%
Phosphoric acid .... ................. 3%
Potash .............. ..... ........... .................. .. 8%
But the following is more often used,
Available nitrogen ............................. 3%
Available phosphoric acid ........................................ 7%
A available potash .......................................................... ..... 6%






72 SOILS AND FERTILIZERS

Cotton
(otton is "eas) on land, but the clean cultivation results
in the leaching and washing of the soil A crop of 300 pounds
of lint removes from the soil in lint, seed, stalks, etc., about 44
pounds of nitrogen, 49 pounds of potash, and 12 pounds of
phosphoric acid.
Were all but the lint returned to the ]and each year, it would
show no signs of exhaustion The relative quantities of the
various ingredients of cotton fertilizer depends entirely upon
the soil Cotton can be grown on as gieat a variety of soils
as any crop of the Southern States. The following may be used
where the soil is already fairly well balanced
Nitrogen .... ....... 3%
Available phosphoric acid ........ 8%
Potash .. ......... 4%

Peanuts
As this plant is a legume and gets nitrogen from the air.
acid phosphate and potash are the chief elements to use in
fertilizing it. The soil should be rich in lime. The formula
should perhaps be 8 potash, 8% phosphoric acid, and the
amount from 500 to 800 pounds per acre. However, this is a
mere suggestion as it is entirely 'epenldent on whether or not
the soil has either cf these elements in abundance: in some
soils, a small per cent of nitrogen should be used

Sugar Cane
Ammonia ....... .. 4%
Available phosphoric acid .. .... 8%
P otash .. ..... ................ ... ............ 4%
Sugar cane should yield from 25 to 40 tons per acre The
amount of fertilizer should be froin 600 to 800 pounds per acre

Sorghum
N nitrogen ........... .--...-- ............ ........... ... 4%
Available phosphoric acid .......... ........ 6%
Aetual potash ..... ..... ............................. 8%
Amount per acre, 600 to 800 pounds.





FERTILIZER FORMULAS 73


Rice
Ammonia .. .... 2%
Available phosphoric eid 10'%
Potash li 4,
When Ithe land ha. ani organ'le il l, scll as peat, the nitro-
gen can be ledueed, and the other elements increased. Fiom
400 to 500 pollnds per acre ia thlie correct amount

Oats
Aimoi nia. ..... i5
Available phophoric acid .. 8%
Potash .. 3%
Appl 4(00 to 600 pounds per dere

Wheat
Nitrogen 3%
Available phosplhone aacid .... 8%
Actual pota.i' 44
Apply 400 to 600 pounds per aree.
In the clay hill counties of Florida. wheat can be grown, and
the hbet pliepalation s to follow a e op of compeas that were
sowi in ,July aind all ll ied under at the t ne of matnritx
that iould best suit the nI..wYig ol hay Thle )peav should be
son late iot the reason tiht tlhe \irn nie ich letter than when
sow n earl. Thiey can be soln in coin at the last plowing Should
they mlatre too airly for soWrig wheat, they should be plowed
uneilr anyway, and allowed to lie till sowing time
If the vine l are rank, as they should be. when the land is
fertile enough to make wheat, it will take a good two horse
plow to turn them under and the ploy should have a rolling
culter in front to cut the vines, so that the plow will not be
continually chokinm It is impossible to do mnuch with iron tooth
drag in these vines-the teeth will have to be slanted back
warl. so as to slide the vmies, that are left uncovered after
the land is plowed
The gain should always be treated for smut before sowing

Grasses
CloIei and grasses for hax or pastures should be fertilized
according to the nature of each Lespedeza is an excellent legume





SOILS AND FERTILIZERS


for general use on dry hills, as pasture, and, when soil is suf-
ficiently fertile to produce rank growth, yields good hay. The
leading farm grasses of Florida are Bermuda, Johnson. -St.
Augustine, and Carpet-others are coming into use.
Where the soil is adapted to Johnson grass, it is well nigh
impossible to kill it. When a farm is well set to it, the owner
has a Johnson grass farm forever. Bermuda is also very diffi-
cult to destroy. Heavy crops of eowpeas, velvet beans, kudzu,
or sugar cane Aill shade it and kill it faster than any other treat-
ment. Carpet grass is easily destroyed and therefore, is to be
leeommnended for lawnmaking, and also for grazing.
Nitrogen ............................................ ... -..---- --- 2%
Phosphoric arid . ................ ............................... .. 8%
P otash .. .. .... ........ ....................... ....... ......... .... ...... 8%

Garden Crops
Good stable manure is the most valuable fertilizing material
for the growing of all classes of vegetables upon all types of
soils. It must often be reinforced with commercial fertilizers.
There is not enough stable manure to supply the demand for
general field crops and near large cities it is inadequate for
truck farming-since the automobile ear and truck have super-
seded the horse in hauhng service.
Stable manure should be well worked into the soil before
planting. The nearer planting time manure is applied, the
finer it should be pulverized.
For asparagus, beets. carrots. cauliflower, celery, cucumbers,
egg plants, kale, lettuce, muskmelons, onions, English peas,
peppers, radishes, spinach, squash, and tomatoes.
N itrogen .. . ......... ..................................... 5%
Available phosphoric acid ...... ...................... .... 7%
A available potash ............... ............ .... .......... 5%
There is no iron-clad formula and this is given as an "indi-
cator" and guide rather than as a specific from which there is
to be no variation.
Following are two good formulas for fertilizing lettuce.
Use the one which seems to suit your soil and general con-




FERTILIZER FORMULAS 75

ditionr best, or if preferred use some other approximating
them
1. Ammonia, 5 to 6 per cent
Available phosphoric acid, 7 to 9 per cent.
Potash, 8 to 10 per cent
2. Ammonia, 6 to 7 per cent.
Available phosphoric acid, 6 to 7 per cent.
Potash. 6 to 7 pet cent

Apply trout 1,500 to 2,000 pounds per acre, and while tiie
crop is growillg top-diest with about 150 to 200 pounds of
nitrate of soda per acie. It requires about three pounds of seed
to sow an acre, ot one ounce to e ery 250 feet of drill.
IBaTket tfoi shipping can be obtained from the vegetablee crate
manitaclurersl in any section of the State

Egg Plant
Thji i one ciop 1hi1ch Ie(|iPes plenty of potash fertilizer,
and on will find it will pay to broadcast the field with a ton
ot kanlmi harrowing it in Next iay the field off in furrows,
the >iidth you wish the rows apart, which is from four to five
feet, setting the plants about three feet apart in the row; using
1,500 pounds of fertilizer in these furrows which should ana-
lyze as follows: Ammonia, 5%, available phosphoric acid, 4%;
lotash, 9; C(oler it well and see that yon get it well mixed
with the soil.

Beans
Ammonia ........... ..... .... .. ... 3%
Available phosphoric a d ... ................... 7%
Potash .......... .................................. 7%

Or, per acre-
Bone meal ..................... .......... .... .. 1700
M uriate of potash ... ................... 300
Or, per acre
Nitrate of soda ................... 100 pounds
Acid phosphate ........... .............. .................. 400 pounds
Muriate of potash ............... .. .. .... 100 pounds






76 SOILS AND FERTILIZERS

Cabbage
Iabbage needs a very rich soil. Where stable manure cannot
be -cmlred 1,000 to 2,000 pounds of fertilizer may be used in
somellinig of the following proportion:
Nitrate of soda .... ................... 300 pounds
Bone meal .......... ........................ ....... 500 pounds
Muriate of potash .................. .............. 200 pounds
It should be well incorporated into the soil before planting.

Celery
Either of the following fmla formula commnerela] fertilizer
are good for celery. and tie one which seems best adapted to
the soil and conditions can be ised, or any other approximately
similar:
1. Nitrate of soda ............................ ............ 300 pounds
Fish scrap ......... ..................-- ....... 800 pounds
Acid phos., 16 ..................... 600 pounds
Muriate lotash ....................... . 300 pounds

2000 pounds
Yields
A m m onia ....... .. ................... ......................... ... 6.9%
Available phosphoonr acid .............-... .. 5.5%
Potash . ................ ............. ... ..... 7.2%
2. Nitrate of soda -................. ..... 50 pounds
Dried blood .... .................... -................ 600 pounds
Acid phos.. 13% ............. ............... 850 pounds
Muriate potash ......................... ......... 300 pounds

2000 pounds
Yields
A m m onia .......... . ........ ..................... . 7.2%
Available phosphoric acid .- .................. 5,5%
P otash ........... ................ .. .............................. 7.8%
Drrii g the growth cf tle crop from one to tno tons per
acre of the aho e may be applied between the rows, and from
tno to four hundrll ed pounds of nitrate of sola per acre as a
top-dressing in four equal applications at about four different
times.





FERTILIZER FORMULAS 77


Grapes
From 500 to 800 pounds per acm, of a fertilizer containing
10ic of potash. S'i or phosphoric acid, and 3I' of nitrogen
would be a a average application.

Citrus Fruits
Tile expeie'leited clitt rl ] iiit tFiwi has learned 1)y expftlelle(
the killd amount, ill frequent) of use, of fertilizer for his
grole Thlie noteomel to a citrli section houii colonsult glrowers
of long eg\perience in his locality,
Nitrog ii pla', an important p1). in the p)rduction ol' new
WOO 1 and leatf growth Exce I.f niitrogen jirodluces dir-back,
Siichl causes the bark it becomlln thick skinned ind puffy Phos-
lphorus is necessary lor the p1rop1 development of the fruit
ulphlate ot potd-iilln is Hvually prielrable to tie iniiate as
ile ialttr soinitiiti has an iilljurious effect on citrus trees.
l[e nrom (l oe to il thee pounild ]per tiee for yolun (rees, ac-
cording to age, of
N itrogen . .... .................
I'lio phl orui ....... ................... .... ............ .... )3'
P otash .. .................. ..... .... ................... 3 1
Apply in early sfprinig, il-sihinrlciO, and ill September, In-
crlase tll is about ai pou))nd a ye ar until thel tlrote are five or six
ears old. amid1 legin to hear cotiei) i o l elrops.i ThPI use Ilhiec
applications pel ear with
N ilrogen ........... . .. .................. .. 4 ',
Available phosphoric acd ................. 8
Polta1,1 .... .... .. ........ ......... .. .. ...... 4',
Apply ti caily -prin'g, airn mid-suniiner. Thle fall ap)lhlvation
should be Ibctwenii November 13lthl and TDecelber 13th with
tile iitlo'epn lea eli'd( to 3, Without o lllinging thie other
materials.
Trees well bearing from tren x\air old iP li) ouild receive
fiom 15 to 30 poulids per year. Older and lheay-lhelrini Itree
receive flom 30 to 75 pounds o I'ertlhzer per annuin \\llier no
green crops are turned under, anid unless the tees hli e a
great distance bletwo'on them g'r(een crops ertlnot be sICeess-
tully growD.





SOILS AND FERTILIZERS


Judging by the elements taken from the soil by a citrus grove
the formula of chemical manues per acre of orange trees, will be:
Nitrate of soda ............................... 560 pounds
Superphosphae of lme (16%
soluble phosphoric acid) .................... 612 pounds
Sulphate of potash ............................ 170 pounds
Obviously, however, this general formula must not be adopted
without reference to specific conditions; it must be modified
to meet the requirements of each particular case, according to
the nature of the soil and the state of vegetation in the
plantation.
When lime is needed for the element calcium, as chemical
analysis will show, or to correct acidity, as the litmus paper
test will indicate, apply lime carbonate or hydrate.

A Word About Formulas
A standard for designating the ingredients of complete fer-
tilizers by numerals has been adopted by control officials and
the fertilizer trade. The nitrogen or ammonia is placed first,
the phosphoric acid second and the potash last. The fertihzer
tags of Florida follow this standard, which means that a nu-
merical formula would mean that the first number stands for
ammonia or nitrogen, the second for phospohric acid and the
third for potash
With this understanding, a formula 5-8-3 means that 100
pounds of complete fertilizer contains five pounds of nitrogen or
ammonia, eight pounds of phosphoric acid and three pounds
of potash.
As a ton is two thousand pounds it contains twenty times
as much of each fertilizing ingredient as a hundred pounds of
the fertilizer contains
Therefore:
To ascertain the number of pounds of each ingredient in ah
ion of mixed fertilizer:
Multiply the per cent required by 20.
For instance: In the above formula, 5 multiplied by 20 equals
100, 8 multiplied by 20 equals 160; and 3 -multiplied by 20
equals 60. Therefore one ton of this mixture would contain:





FERTILIZER FORPII'LAS 79

Phosphoric acid .. ....... .................................. 160 pounds
N nitrogen .... ...................................... .......... 100 pounds
Potash .................................... .......... 60 pounds
The remainder of the weight is extraneous matter.
To ftnd the quiwntili of an iegredient needed to .ippl the
'per cent required:
Diride the na mbcr of pounds of the Ingredients in a ton by
the lnuber of pound. of that ingredient in a hundred pounds
of the material containing it. The result will be the number of
pounds of raw material itsed to give the percentage desired
in the formula.
It we use acid phosphalte ronatainin 16 per cent ot available
phosphorie acid, to find the quantity of raw material needed
to supply the per cent of the ingredient required we must di-
Nlde the number ot pounds required in a ton by the 16
If cotton seed meal is ued to obtain the nitrogen the numlbel
of pounds required in a ton must be divided by 6.18, as that
is the per cent of nitro'uen in a hundred pounds of the meal
If we use nmurlate of potash to finish the formula we use
a material that yields 51 per cent of potash; but we can count
in 1.8 per cent of potash from the cotton seed meal that we
used which would reduce the requirements of Iuriate, and
we deduct the number of pounds that has been added by the
meal from the number of pounds to be added by the muriate
In like manner if the filler that is used contains a\ailahle
nitrogen the per cent thus added ma) be deducted from the
cotton seed meal. This is seldom the case, but it might be so
if properly prepared peat is used as a filler. In the above illus-
tration the use of peat would lessen the amount of cotton seed
meal, which. in turn. would lessen the amount of potash fur-
nished by the meal However, it is not necessary to split hairs
over such small discrepancies in proportion. The rules for cal-
culation herewith given are approximately accurate in results,
and entirely practical but it will show a little over a ton.

To Find the Analysis of a Given Mixture
Suppose a farmer has on hand available material which he
wishes to use in certain proportions and wants to know the





SOILS AND FERTILIZERS


analysis of the proposed mixture. Take 1,000 pounds of acid
phosphate 16 per cent; 800 pounds of cotton seed meal, and
200 pounds of kainit.
One thousand pounds of 16% acid phosphate contains 160
pounds of available acid; eight hundred pounds of meal con-
tains eight times 618 or 50 pounds of nitrogen.
Two hundred pounds of kainit at 12 5 pounds per hundred
contains 25 pounds of potash. The eight hundred pounds of
meal contains 1 8 pounds per hundred, or 14 4 pounds of potash.
Therefore the above mixture contains phosphoric acid, 160
pounds. nitrogen. 50 pounds; potash, 39.4 pounds.
To find the per cent of each of these materials in a ton we
divide each by 2,000 with the following results: Phosphoric
acid, 8%, nitrogen, 3%; potash, 2%; formula, 8-3-2.
"C'onverting" elements into equivalents:
To illustrate' Ammonia contains 82 per cent of nitrogen.
Therefore to "convert" per cent of ammonia into nitrogen
multiply by 0824.
To "convert"' per cent of nitrogen into equivalent in am-
monia multiple, by 1.214.
Three per cent ammonia multiplied by 0 824 equals 2 47 per
cent nitrogen.
Two pei cent nitrogen Imultiplied by 1.214 equals 241 per
ePnt ammonia.
To comXert ammoiia into protein multiply by 5.15; nitrate
of odal into nitrogen multiply by 0.1647; nitrogen into protein
multiple bh 6.25; muriate of potash into actual potash multi-
ply I,. 0.632; actual potash into muriate multiply by 1.583;
sulphate of potash into actual potash multiply by 0.541; actual
potash into sulphate of potash multiply by 185; nitrate of
potash into nitrogen multiply by 0.139; carbonate of potash
into actual potash multiply by 0.681; actual potash into car-
botite of potash multiply by 1.466; chlorine in kainit multiply
potahl (K20) by 2.33.
In calculating values you simply take the number of pounds
ol each ingredient in a ton and multiply it by the price of
the materials used. The ruling price used to be 4 cents per pound





FERTILIZER FORMULAS


each for phosphoric acid and potash and 18 cents for nitrogen.
But 16% available phosphoric acid was woth $28 00 a ton pur-
chased for cash in ton lots at Florida seaports; sulphate of
potash, $180.00, nitrate of potash, $13000, sulphate of am-
monea, $137.00. (October, 1920).

Prescribing Fertilizers
Fertilizer preseri options are at best founded on conclusions
drawn from general/ation rather than from positive knowledge.
The chemical composition of the soil and its mechanical con-
dition should be kno~n but rarely is The average composition
of the crop to be giown, and the relative amounts of the three
principal elements-nitrogen, phosphoric acid and potash
which a given crop of a given yield will extract from the soil,
should be known, and whether or not the crop is nleuininous.
Whether lands are sand,, ela, hill, bottom, drained or wet,
been in pasture or cultivated, plowed deep or shallow, crops
rotated or not, etc these items should be known the results
of past experience in fertilizmin land under consideration, yel
low foliage indicatiii lack of nitrogen, hedding of fruit in-
dicating need of potash Where ifliavor is an item potash should
be used in the sulphate rorm. Witl pineapples and tobacco car-
bonate of potash and cotton seed meal are adapted
All fertilizer tags should specify the sources from which the
ingredients are derived and the per cent derived from each
source They should also state the kind of materials used to
make up the filler and the percentage of each material used,
and pounds of available plant food per hundred Protein, fat,
sugar, starch, etc.. are animal food terms and do not belong
in fertilizer formulas.






CHAPTER VI
The Meaning of pH

E. J. DAVIs, Reg. Eng.
(In Bio-Dynamics, 1948)

To pronounce the expression "pH" correctly, we speak each
letter separately, as "p" "H". The letter "p" stands for the
German word "Potenz" which means 'the power." However.
in its truest meaning, the "p" stands for the quantity, the
abundance, the amount. The amount of what? The amount of
Hydrogen molecules. The letter ''H" in the expression "pH"
stands for the element Hydrogen. pH has to do with two things:
acidity and alkalinity. First of all, let us thoroughly under-
stald that it IS possible to have acidity and alkalinity at the
same time. In fact, when soil is neutral we have a case in
which the soil is exactly as acid as the soil is alkaline. When
N ater is neutral, it contains exactly as much acid as it contains
alkali. Whenever a substance contains more acid than alkali, we
say that the substance is acid. Whenever a substance contains
more alkali than acid, we say that the substance is alkaline.
What is it which make. a substance acid instead of alkaline?
What is it which makes a substance alkaline instead of acid?
It all begins with water. We were taught that water has the
formula of H20, but now ne have found that whenever the
daylight falls upon afterr the water has the formula of H OH.
Sometimes thi, formula is expressed like this: H(OH). We
have therefore accepted the formula for water as H(OH) instead
of H20 because Il*ie formula 11(O01) helps us to understand
chenistry. and to understand the importance of pH, in a much
'cearer manner. In the formula 11(011) the first H stands for
Hydrogen and this Hydrogen has a positive charge, sometimes
called a "plus" charge, ol energy. The (OH) is called the
hydroxyl, and hi droxyl means hydrogen combined with oxygen.
The letter "l" in the word "hIdroxyl" comes from the "1"
in the word "radica/. So., the word "hydroxyl" actually
means "a radical, or unusual, combination of Hydrogen with
Oxygen. The (011) always has a negative charge, sometimes
called a "mlinls" charge of energy. The first H in water's
formula of 11(011) is always acid. The (OH) in water's for-
mula is always alkaline.






THE MEANING OF pII 83

Therefore, pure water means that the pH of that water is
exactly neutral Why? Because pule watEr is H(OII), and as
we explained above, every molecule of pure water has in it
the same amount of Ii as it has of (OII), and since H has one
"positive" charge of energy, and since each (OH) has one
"negative" charge of energy, the puie water is exactly'balanced
in energy, and has a neutral pH.
It is foolish to say that the soil is "slightly" acid and it is
foolish to say that the soil is "slightly" alkaline No two per
sons have the same understanding of the word "slightly," and
that is why the scale of pH values was created. The pH scale
begins at 7.000 and goes in two directions It goes downward
to zero, and upward to 14 The figure 7 000 is NOT seven thou-
sand It is seven, and a decimal point, and three zeros Neutral
pH is 7000, and as more alkali is added to the soil the pH
goes higher and higher As more acid is added to the soil the
pH goes lower and lower For example If you start with a
neutral soil that soil has a pH of 7.000 This means that your
soil contains exactly as many II units as it contains (OIl) units
Suppose you add some soda water (tlie soda water found in
drug stole fountains) to Iour soil Soda water is carbonic acid
and its formula is HI (COs. By looking at this formula you will
note that the formula contains some H units, but no (OH)
units. Thus, when oni add soda water to your soil you are
adding II unit, to your soil and II uml, are always acid So you
are actually] adding acid to o our soil Now your soil will no longer
be neutral. Your soil will not longer have a pH of 7000. Yonr
soil will have a reading lower than a pH of 7 000 because, as
we stated above, the p-I scale becomes more and more acid as
we go from 7.000 on down to zero At a later place in this
article we will explain how to determine exactly what the pH
of your soil is. Suppose. instead of adding soda water to your
soil, you decide to add some kind of alkaline such as limewater.
The formula for limenater is Ca(OI)2 which means that every
molecule of himewater contains two units of (011) So, we are
actually adding alkali to the soil because (OH) units are al-
ways aalkaine Now )our soil will no longer be neutral. Your
soil will no longer have a pH of 7000 Your soil will have a
pII reading higher than 7.000 because, as stated above, the
pII scale becomes more and more alkaline as we go from 7 000
on up to 14. It is extremely important to remember that the
addition of H units to the soil does not mean that we are re-






84 SOILS AND FERTILIZERS


moving any (011) units from the soil. No, the (OII) units are
there till the ~un grows cold and the leaves of the judgment
book unfold' And it is equally important to bear in mind that
when we add (OH) units to the soil we are NOT removing from
the soil any iH units Thus you can now understand how we
can have acidhit and alkalinity in the soil at the same time.
The pH scale will show the exact difference between the amounts
of alkalinity in the soil. and the acidity in the soil.

The pH scale looks like this:


pI of zioa man there ale 10,O00O00 titmE as mny I uin anA (OH units
pH of 1.000 " 1 000, " " "


pHi f 6,000 10 ".. .. .. .. ...
pHof ,000 TheSame ". o
p of ,000 10 OH)
pHof 9,000 100 it
pHof 1.000 1,00
pHof I1,000 10,000 "
pHofi.c00 100000 "
pH of 13, 000,000
pH of14 1 0,00,000


To tell the exact pH of your soil is a simple and quick opera-
tion. It is necessary to obtain small, inexpensive testing appa-
ratus. Each value of pH has a different color. When you match
the color of your soil-sample with the color of the glass tube in
the testing apparatus you will know the pH of your soil. In
a later article we will attempt to show relationship between
the proper pH and the proper soil and the proper crop






CHAPTER Vll


Composting and Mulching

F B SuMITH and GEO ) THORN1ON
Unire'rsti ,of Flor da College of A ticult/le

The full anlfiicance' of organic matter" in .oils is realized
only when the transitory nature of this material is considered
In addition to the impoitanrie attached to it as a soil con
stituent, oranice matter exerts benefiial lfeirts on the physical,
chemical and biological properties of sods
Organic lmtter furnishes a practu ami manintainlung that important and (expensive plant food ele
meant, nitrogen ft also se res as a foo i for soil bacteria that fix
the nitrogen of ihe air into foinns which mav easily be con-
verted into a ailable plant food Thus. the nitrogen content
of the soil can be lnot only maintained but actually built up by
means of oranla matter
ThrouIh Ite use of o0gatli i.tteP large almouints of plant
food may be made available BI the use of certain kinds of
organic matter the opposite effect iia\ be produced, that is,
available nitrogen and phosphorus may be locked up in un-
available forms aind stored for future use. This may be espe-
cially desirable when there is no crop on the land and there
is danger of loss from leaching.
It has been found that a heavv application of straw or woody
organic matter stimulates those soil microorganisms which re-
quire large amounts of available nitrogen and phosphorus for
their growth and as long as the straw lasts these elements will
be held in the bodies of these mioeoorganisms Obviously, it
would be unwise to make such an application immediately
before planting a crop because the mneroorganisms would then
be competing with the crop for food and as a result the crop
would suffer
When the organic matter is well rotted and becomes a part
of the soil it is then a storehouse for plant food It takes part
in the exchange reactions in the soil, that is, it reacts with the
mineral plant foods and holds them in a readily available form
for the plants This is especially true of such essential plant
food elements as caleium and iron





86 SOILS AND FERTILIZERS

Another very important characteristic which organic mat-
ter imparts to the soil is its capacity to hold water. When or-
ganic matter is wet, it swells up much like a sponge and aill
hold large amounts of water. This is a very important factor,
especially during a season of drouth. This property of organic
matter to hold water is utilized in erosion control.

It is obvious that one should maintain the organic matter
content of the soil. Over a period of years the financial return
is larger if the organic matter is maintained than if it is allowed
to run low.

Composting
To maintain an adequate supply of active organic matter in
the soil is sometimes most difficult, e9peeially in the lighter,
well aerated soils under moist, warm conditions Therefore, it
is necessary to make frequent additions to the soil under such
conditions to maintain a proper amount of this important con-
stituent. Barnyard manure is an excellent source of active or-
ganic matter but the supplv of this material is never adequate
for all needs Consequenitlv. the practice of composting has
developed to meet this need. Compostinr cannot be recommended
for general farm use, but where conditions are favorable and
facilities are available at little cost, artificial manure may be
produced which will be equal in alue to animal manure
Any plant material may be used to produce a compost Di-
rections for the preparation of composts are simple and easy
to follow and necessary materials are usually available in
abundance Leaves, grass, weeds, garden refuse and kitchen
wastes, peat, green crotalaria, water hyacinths, manure and fish
scrap, where available, are all suitable materials.
Green, succulent materials decompose more rapidly than dry,
mature graos and veeds Green crotalaria usually contains 75
to 80 percent of uater, and 400 to 500 pounds of green nmate-
rial are required to supply 100 pounds of dry matter The pro-
portion of water is even higher than this figure for the water
hyacinth and 1,000 pounds of green material are required to
supply 100 pounds of dry matter. The water hyacinth is an
excellent material for composting in spite of the large quantity
of water that must be handled it contains sufficient moisture
for decomposition, making it unnecessary to add water to the





COMPOSTING AND MIUL(CIING


compost, and in addition it is well supplied with potash and
contains sufficient nitrogen for relatively rapid decay
Oldiuarly it will be necessary to supply nitrogen for the
microorganisms which bring about decomposition ii the plant
materials composted are not rich 1i this element. An alkaline
source of nitrogen such as cyanamid should be used to neutralize
the acidity produced in decomposition Other sources of nitro-
gen, such as ammonium sulfate, mam be used but this form of
nitrogen labes an acid csidiio which must be neutralized by
applying a small amount of lime. Phosphate and potash also
are usually added to ((compost A good mixture to use on woody
plant materials s i made with about 75 pounds of c anamid,
65 pounds of finely ground rock phosphate and 10 pounds of
muriate of potash Superphosphate may be used instead of the
rock phosphate. One hundred fifty pounds of this mixture will
be sufficient lot a ton of dry plant mat eral A formula often
recommended consists ol 45 pounds of amnllonium sulfate, 15
pounds of uperlphosphiate and 40 pounds of finel? ground lime
stone. One hundred pounds of this is used per ton of dry mat
ter. The addition of 10 pounds of inuriate of potash to this
formula would probably be desirable
The compost heap is made of convenient than 10 feet square and 3 to 5 feet high The top should be left
flat or with a slight depression in the center to catch and hold
rain If space permits, a long row 8 to 10 feet wide and 3 to
5 feet high makes a convenient compost heap In either ease
be sure to leave the top flat 01 slightly depressed rather than
heaped up or rounded
If diy materials are used it is obxions that water must be
applied to insure rapid decomposition On the other hand, too
much nater should not be used as it will exclude air and delay
the decay processes A good practice to follow with dry materials
such as leaves, grass and weeds is to make a layer about 1 foot
deep. wet thoroughlx with water and pack Spread a layer of
manure 4 to 6 inches deep over this la oer of wet material. Then
spread uniformly a quart of superphosphate per 100 square
feet of compost iThe process is then repeated, making alternate
layers of dry material and manure unlil the compost heap is
about 3 to 5 feet Ingh Where available, green erotalaria, cow
pea tines or beggaroeeds may be used instead of the manure
If manure or green leguminous plant materials are not avail-


87





SOILS AND FERTILIZERS


able. about 15 to 25 pounds of the cyanamid-phosphate-potash
mixture should be used on each layer of plant material in the
compost
Compost made in this way will usually begin to heat after
2 or 3 days It should be watched carefully at this stage and
not allowed to dry out Neither should too much water be added
The compost should not be distrubed at this stage After 3 or
4 weeks it ma) be forked over, mixing the dry and moist de
composing parts to insure a uniformly decomposed material.
After another period of 3 or 4 weeks in warm weather the
compost should be thoroughly rotted and ready for use. Com-
post prepared in this manner is not only a valuable source of
nitrogen but also an invaluable material for garden crops on
any soil and is especially beneficial on sandy soils

Composting Leaves
Dry leaves as a general rule do not decompose quickly he-
cause they do not wet easily and they dry out quickly. They
contain relatively high contents of tannins and lignified ma-
terials These substances are slower to decompose than the car-
bohydrates and proteins of other plant materials Dry leaves
are also low in mtrogen, an element necessary for microbial
decomposition. The decomposition products are acidic and this
limits the microbial population chiefly to the molds It is be
cause of these characteristics that leaves and leaf mold make a
good mulch. The slow decomposition and gradual release of
the ash constituents to the soil in a readily available form
helps to hold soil moisture, prevents excessive evaporation and
improves fertility
Leaves may be made into a good compost even without manure
or nitrogen fertilizer, although the addition of these materials
makes a better product and hastens decomposition. A simple
procedure for composting leaves consists of covering a 6-nch
layer of leaves 8 to 10 feet square with a 2-inch layer of soil,
then alternating these layers, keeping the sides vertical and the
top flat. The pile may be built up 2 or 3 feet high. Water
should be applied frequently enough to keep it moist but not
too wet. Under favorable conditions of moisture and tempera-
ture, oak leaves composted in this manner will decompose suf-
ficiently for use in 6 months to 1 year. Because of their thick-
ness and composition, live oak leaves decompose more slowly




COMPOSTING AND 1UL('IIINO 89


than red oak leaves Ieis fi]oml othci dcliliioti tre(, such
as maple, ashi, elm ."ld lickoi,, i'ty be comnlWstvd equally as
ell. atin some I:uln rvln contain a higher ash content and
deconlllose more rapidly.
It is inadvisable to apply (1dr loaves to the soil directly, Com-
posting serves to pre-diUe't tlhe l llln prep et comllpetititiol of
plants anli iiierooIgarlimsiis fr iliilgen alnd ol their plant food
elements 1) y leavIc". pil; o I i) le unfavuora.ble physical condi-
tionI ill s ldy soil iiand iouldl [I) ao1cd, 1,)pecially it rapidly
rPOnTiag ]jilants are to ) ,e ... 1n on the lad oo.0011 after appli-
atiio Thi doe, loot applh to Icaves lsed as a nijleli, as they
liPe not illcorpolated with Oili ill ili (ca'c

Mulch to Conserve Soil Moisture

An impoitani furlntion oi a illiteh often overlooked is that
of conserve ingl moistllrt. A inmlich of lea.es. gra'sI or dead plant
l'-idtl curis down (valpota.tioln, helps to holl moisture il tile
soil an I owners the soil te'leriattre' Sandy soils nulched with
grass and leaves 11 Noti.lli(nr have silo n 2 to 3 percent lore
loilsture tih follow in'g Maiy than nllirmu'lcled soil. While this
is a saiall aloiount. it i s sufficient to make lthe iiffeirenl be-
'weeD ilod lplanl growth and lillle or nto gro'thl onl saldy
soils. Plaill roots (xtlend lown into the soil in search of niois-
lure [n s doihn, ordinal ly, the\ "onO a\ay fromn the highest
concentration i of thle iinIrll] p)ilit food elements. With a good
nmulelh of orl nii' milttli the sul'facie soil is kept nloist, pro-
Imoting the development of feeder roots near the siirface ol tile
soil and eonseq(iiently il the zone of highest fertility. The im-
pliOed i01oistlre oii .dh ll .0ill anlicied lplahit food constituentsg
result n1 illrePased vigor andl better plant growth A miilel will
prove beneficial oil o av\ textied soils as ll as oil light
textured olle, but tllh' benefit fl l't Iinproved moistilre (ondl
lions will be greatest (i sanTly soils,
A miulclh canii e re'ommllended( t0o ide( ease evaporatioTn, tlans-
piratioll losses \ix eedsl, to inllsillat tle soil against excessive
heat, to suippIly a;ilahle plalnt food aind a source of hiltiIus.
In addition. ililclles afford practical neinatode control on ill-
fested soils (see Press Bulletin 586). The conditions brought
about and favored bi mnulehles malk their use highly desirable,
especially on open. sandy soils common under Florida conditions.






CHAPTER VIII


Soil Pests

One of the most serious pests to Florida crops is the nema-
tode It preys on the roots and the following plants are hosts
to it:


1. Okra
2. Tomatoes
3 Eggplant
4 Cucumber
5 Cantaloupes
6 Celery
7. Beans
8. Dasheens
9 Peppers
10. Squash
11. Figs
12. Peas
13. Peaches
14. Roses
15. Old World Grapes
16 Irish Potatoes


Watermelons
Lettuce
Careless weed
Beets
Pineapples
Cotton
Cabbage
Cauliflower
Collards
Sunflowers
Carrots
Bananas
Papaya
Rape
Radishes
Sweet Potatoes


Asparagus
Soybeans
Pecans
Sugar Cane
Mustard
Violets
Japanese
Persimmons
Catalpa
Kudzu
Quince
Peanuts
Peaches
Figs
Tung trees


It has been discovered that the pulp of the tung nut, re-
sulting from the extraction of the oil, has toxic qualities which
renders it a deadly germacide to the nematode.

It is being used on tung groves infested with nematodes.
also on land to be planted to vegetables, bulbs, peaches, figs
and the above list of crops Other remedies are discussed by
Soil Scientists and Horticulturists at the University of Florida
-(By Dr. J. R. Watson, [Tniversity of Florida)

Soil fumigants have been used successfully to kill nematodes
where trees are to be set. We have an experiment at Leesburg
with the Jewel peach planted on infested soil and the trees in
the treated plots made excellent growth during the past year
while trees on the untreated plots have made very poor growth.

Soil sterilzers have been used quite extensively throughout
some sections of the peach producing areas of Georgia. accord-
ing to the information that we have received. Many growers
treat by a method known as "'spot" sterilization, rather than
sterilizing the entire area.

The "spot" treatment is the method which we used at Lees-
buitr last year and we are setting up another experiment here
at Gainesville this year We are sterilizing the soil over a cir





SOIL PESTS 91

eular area 8 feet in diaLmter ant with the trees set in the
center of th}iee LtPr'li/ I a,;eat A ppreoltIly eonl ean itse eitlIer
DD. Ethylene Dibitrcide o0 ( h]oi opil in Ti' Chloropierin,
hol eer, is niole oxpeIin l e arid dlifticult to handle than the other
tvo-(B,? ( If hilackmno, jIoTniiitivisi, I ineriti of Floi
ida, Gainestille, Florjlau
We hale on'iducted l rill)ber 1o experilteliits o1 lhe effect
of soil iilnlpasil, lteisrielrrce a.d illseetieiles oil microbiological
action i i ln u*il d as chlot1pieun. DD, )DT, and 2 4-). In
general all fi[e i niteit lrl redlite tihe inirmbe aind activity of
the ,oil m'lic-Ct imllSl i oiie aie inoroe effective than others
Apparently somlle of the iiaterials pesIhl si rtl.e soil longer
than other,> VWe htiae not tettetl thl(sc lli)at als on the le/unie
bacteria, but nlllfiatliol (eiboli ioxide p)lOodltion dand i llnum-
bers of molnl bacteria and acjininiee, have been studied The
materials hale a partial sterilization effect. Microbial action is
not completely stopped but retarded lathl effectivel'l We do
not know the practical importance of this sterihli.in effeet. Tile
question a, still inder In,, tgi'ition-B B F B Smith. IHad
of Depaitmlent of Soils Ulnnilsit of Florida, Gainesville,
Florida)






CHAPTER IX


Soil Organisms-What They Are and
What They Do

By F M IAST, Prof of Soils and Fertlhers; Addiess
Delvered at Citrus Seminarq--1917

A vast number of organisms. animal and vegetable. live in
the soil The greater part of these belong to plant life, and
these comprise the forms of greater influence in producing
changes in stiuctire and composition that contribute to soil
productiveness. The majority of these organisms are so small
as to be seen only b' the microscope, but still a large number
range from this size to the larger rodents. Organisms of the
soil may be classed under two heads, macro-organisms, and micro
organisms The macro-organisms will only be briefly mentioned.
since they are not of much importance, and since owing to their
size we understand more fully.

Macro-Orgonisms of the Soil
These may be classed in two heads
Animals-rodents, worms, insects
Plants-fungi, plant roots

Animal Macro-Organisms
Rodents-Such as the ground squirrel, the mole, the gopher
and the prairie dog are familiar examples.
Worms-The common earthworm is the most conspicuous
example.
Insects-Ants, beetles, and myriads of other burrowing
insects.
All of these improve the physical condition of the soil by
their burrowing habit, which has a tendency to loosen the soil.
while some have the additional effect of actually making the
mineral plant food more available. For example, the earthworm
burrows its wav by passing through its alimentary tract the
soil, and while it obtains food from the organic matter, the
mineral matter passing through is made more available by
being acted upon by the digestive juices.





SOIL ORGANISMS 93

The Plant Macro-Organisms
The large fungi and the roots of trees are the most notable
examples. The large fungi are chiefly concerned in bringing
about the fir t stages in the decomposition of woody mailer,
which is disintegrated through the growth, in its tissues, of the
root mi celia of the fungi. These break down the structure and
thus facilitate the work of the decay bacteria. This action is
confined to foiesls an id is not of gleat imporl)ance in cultivated
soils. It is thought, aso. that some of these fungi have the
power with the aid of ihateria of appropriating the free iitro-
geni of the air, and thus have an action similar to the action of
]eguminous plants.
Plant rootn declye ing. leave behind lar'e qualtities of or
ganic matter, and when this decotlijposes the openings are left,
and in this aiy inmproe the stilructre of soils.
The niacro-organisnis have only been biefly discussed so
as to allow inole time oni the no re illll)Oltanllt division of soil
organisms.

Micro-Organisms of the Soil
The sweater part of ihese belong to plant rather than animal
life Of the animal kind. the only organinis of well-known
economical iinmportancli alr the nclllito(de, which are rijurious
to plant liie.
Plant nllro-ooriganlisnil may lie classed as slime molds, hbae
teria, fungi and algae
We may fullrtler divide thle micio-organism s lo the soil in two
other classes: First-tbhose injurious to higher plants; second-
those not injurions to higher plants.
The micro-organismis belonging Il the first class are mostly
confined to fungi, bacteria, and injure the plant by attacking
the roots Some of the most important disen ses piodueed by
these organisms are Wilt of cotton, watermelon, flax, tobacco,
tomatoes and other plants; damping off of a large number of
plants; root-rot; galls These o-rganlislm are easily spread, and
the soil infested mith them f ill remain so for a long time

Methods of Control
Prevention is the best defense, for once the disease has pro-





SOILS AND FERTILIZERS


cured a foothold, it is practically impossible to eradicate all
of its organisms Without going into details, the following
methods have been practiced with more or less success. Liming,
chemical, steam, planting resistant varieties and rotation. The
two latter practices have met with better success than an) of
the others with most diseases of this kind under general farming
conditions.

Plant Micro-Organisms Not injurious to Higher Plants
Of these are large numbers of different species of micro-
organisms that are beneficial. The three general classes most
active are bacteria, molds and fungi. Of these three, the bacteria
play the important role.
The chief function of these organisms is to remove the re-
mains of plants and animals that would otherwise accumulate
to the seclusion of other plants By the process of decompo-
sition this organic waste is broken down, nitrogen and the
minerals are changed from a complex compound to a simpler,
which can then be utilized by the growing plant. The elements,
carbon and hydrogen, are kept in circulation, and, unfortu-
nately, some nitrogen is liberated to the air and results in a
total loss. This, however, may be recovered, and even more nitro-
gen added from the air by certain other organisms, which will
be touched on later.
One must remember that there are many different species
of bacteria and many of the fungi and molds, and all play
an important pait in this process. Some start the process,
while others take up the work where the first discontinued
until finally we have the simple products mentioned above
Another function of these organisms is to act directly or
indirectly upon the insoluble minerals of the soil Indirectly
the acids thrown off by the organisms tend to have a soluble
effect upon the minerals. Directly the organisms actually attack
the minerals themselves and render them more available Just
the exact extent of this latter is not known, but enough inves-
tigation has been made to justify the conclusion of the impor-
tance of this action.

Bacteria
Because of their importance the bacteria will be discussed
separate) and more fully than the above discussion permitted.




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