Florida Quarterly Bulletin
Department of Agriculture
Commissioner of Agriculture
Entered January 31, 1903, at Tallahassee, Florida, as second-class matter
under Act of Congress of June, 1900. "Acceptance for mailing at special
rate of postage provided for in Section 1103, Act of October 3, 1917.
authorized September 11, 1918."
T. .J. APPLEvARN, PRINTER. TALLAHASSE, FLO*II
General Principles ........................
Sources and Function of Fertilizer Elements .....
Home Mixing ......
The Uses of Liime
.. I E... .
. .. .. .. . .. ..........
Soil Analysis ..............
Purchasing Fertilizer .......................
Citrus Fertilizer Experiments ............
Practicability of Citrus Fertilization......
Cotton Fertilization ......................
Fertilizing Peaches ..................
More About Fertilizer ......................
Useful Tables ...............................
. . .. 10 1
Effect of Bacteria on Soils ................. ..... . .. 115
Iaws Governing Sale and Inspection of Fertilizer in Florida 119
SOILS AND FERTILIZERS
By T. J. BROOKS, Chief Clerk Department of Agriculture
IIYSICAL man is imide up of some fifteen of the
eighty known elements composing, the material uni-
verse. 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, weathering, and decomposition. The min-
eral kingdom is the basis of the vegetable and animal king-
doms. Plants and animals are partly mineral-man is no
So far, science has been able to isolate eighty distinct
physical elements. At least ten of these are essential to
the growth of plant life-carbon, hydrogen, oxygen, mag-
nesium, iron, sulphur, calcium, nitrogen, phosphorus, and
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, cow-peas, alfalfas, etc.-gather part of their nitro-
gen from the atmosphere. They accomplish this by means
of microscopic organisms which live in small nodules or
tubercles found on the roots.
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.
SOILS AND FERTILIZERS
So that only about five per cent. of the material of
plants actually comes from the soil. Only minute amounts
of magnesium, iron, and sulphur are required and they
are present in 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 ten elements essential to plant growth, need
give the farmer but little concern.
The efficiency of soil is measured by its capacity to sup-
ply 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 en-
vironment must exist in well-balanced proportion and
abundance to insure bountiful yields-even from the best
of cultivation and the absence of diseases and insect or
animal enemies. The vast variety of climates, soils, and
soil conditions determine the kind and location of the many
varieties of plants.
Generally speaking, the water, heat, and air are fur-
nished by nature. It also furnishes the food in great
measure, but of recent years a great deal of artificial feed-
ing of plants has been practiced by farmers. This gives
rise to the manufacture and use of fertilizers.
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 combined with other elements, and plants
can only appropriate their foods when they exist in cer-
tain combinations, and under certain physical conditions.
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 avail-
ability of plant foods. The mechanical condition, which
cannot be ascertain by chemistry, goes farther in de-
termining 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 avail-
ability is largely determined by the physical or mechani-
cal condition of the soil.
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 pro-
ductive. 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 arid lands of the west, rich in
the elements of plant food, but not productive until irri-
gated. 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 soil to insure the best
result from a certain crop can be ascertained only by ac-
tual test in growing it, was a sore disappointment to
agronomists and is disconcerting to the farmer.
There are several methods used in determining the avail-
ability of plant foods in fertilizers; the neutral perman-
genate 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 Kjecdahl
method is also used to ascertain the nitrogen content of
ingredients making up a compound fertilizer, but the
availaiblity for plant food of the elements contained is
not so easily registered.
All the power of growth possessed by plant life is de-
pendent 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 fertilize when we apply either
ammonia, phosphoric acid, or potash in an available form.
A complete fertilizer must contain all three, but not neces-
sarily in equal parts. The food that is present in least
amounts limits the crop. Plants need a "balanced ra-
tion" the same as animals.
SOILS AND FERTILIZERS
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 like that of
body-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 through 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 fibrous 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,
transpired, or breathed off into the air. A process of ex-
change, of transpiring, and absorption takes place in the
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
Plants exposed to light develop chlorophyl, which is
the coloring matter that gives the shades to certain por-
tions of the protoplasm. The function of chlorophyl con-
sists of the absorption of carbon-dioxid gas, resulting in
the transformation of oxygen and the formation of new
A plant food is much more available when locked up in
some mediums than in others. Certain sources of nitro-
gen yield it up to the action of soil moisture more readily
than others. This makes the source of nitrogen, phos-
phorus, or potash of importance 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 Agricultural
Chemistry. It was he who discovered that plants feed on
soil chemicals, 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
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 chemis-
try 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 determining 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 availability of plant foods in commercial fertilizer.
The law of Florida requires that the tag state the pounds,
available ammonia, insoluble ammonia, available phos-
phorus acid, water soluble potash, and the sources from
which these elements were obtained-but it does not re-
quire 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 avail-
able for plants. Amoniacal nitrogen is converted into
nitric form by the action of bacteria and soil chemicals
in rather a short period. Organic nitrogen takes some-
what 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 its foliage and
this combines with the oxygen in the water taken up by
10 SOILS AND FERTILIZERS
the roots to form carbonic acid, which in turn, desolves
compounds supplied by the soil solution. The hydrogen
in the water combines with nitrogen to form ammonia,
and this combination depends 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 action of bac-
teria. The tilth-depth of tillage or amount of soil avail-
able for plant roots-of soil is as much a determining fac-
tor as the mere presence of plant food elements. Often-
time the farmer will use barnyard manure in connec-
tion with commercial fertilizer, in which case it is an in-
determinate equasion 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 com-
mercial fertilizer needed could be determined.
SOURCES AND FUNCTIONS OF FERTILIZER
SURE 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 Govern-
ment has a large plant for extracting nitrogen 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 ma-
terials are called nitrogenous or ammoniates. It is often
confusing to laymen to use the words "nitrogen" and
"ammonia" as synonomous, 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:
Nitrogen. Equivalent to ammonia.
Nitrate of Soda... 15 to 16 18 to 191/2
Nitrate of Ammo... 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 8s1 to 9/2
Cottonseed M. .... 61/2 to 74/2 71 to 9
Castor Pomace ... 5 to 6 6 to 7
Nitrate of Lime.
Horn and Hoof M.
Hair and Wool.
Protoplasm is the physical basis of life and nitrogen
is necessary for its production. The effect of nitrogen on
plants is to build up the body, give rich, green color to
leaf. and vigorous growth.
SOILS AND FERTILIZERS
Too little stunts growth, and too much gives rank
growth with sappy, weak, stalks, and delays ripening.
Large amounts suit plants like celery, lettuce, etc., where
crisp, tender stems and leaves are wanted. For imme-
diate results it is best to use nitrate of soda, while for
seasonal growth other forms can be used. The activity as
well as availability of nitrogen in materials like leather
scrap, hair, or peat, is but one-fifth to one-tenth as much
as that in nitrate of soda.
No organic cell can exist without it has nitrogen in com-
bination with carbon, hydrogen, oxygen and sulphur.
Plants are nourished by the nitrogenous substances con-
tained in the soil and water, and animals by the nitro-
genous substances in plants and other animals. However,
neither plants nor animals can utilize nitrogen unless it is
fixed (non-volatile) in some combination.
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, equiva-
lent 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 which
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 hard-
ened 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 con-
centrating into exportable form the nitrate of soda. After
the caliche is removed from the pampas it is carried in
open freight cars to the crushing house and reduced to a
form which renders it the more readily soluble in the
boilers, to which the broken caliche 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 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.
Four-fifths of the world's nitrogen is contained in the
air. Only one-fifth is present in the soil, animal and vege-
table 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 above every square mile of the
earth's surface there is estimated to be about 21,683,200
tons of nitrogen, while the total area of the earth's surface
approximates 200.000,000 square miles.
The conversion of the nitrogen of the air into com-
pounds available for use may be accomplished in a num-
ber of ways, among which are the following:
1. The direct oxidation of nitrogen and its conversion
into nitric acid.
2. The combination of nitrogen with metals to form
nitrides, which may be treated to furnish ammonia.
3. The formation of cyanides or cyanogen compounds
by the combination of nitrogen with metals and carbon.
4. The formation of a compound with carbide, pro-
5. The direct combination of nitrogen and hydrogen
from its element for the formation of ammonia.
In addition to being so essential to life, nitrogen is the
chief and most used element in explosives. During the
World war when the United States found itself in need of
nitrogen for the manufacture of gun powder and other ex-
plosives the cyanamid and Haber processes-the last two
mentioned above-were recommended by scientists ap-
pointed to investigate the fixation processes. As a result,
the Government built two plants, one at Muscle Shoals
and one at Sheffield, Alabama, utilizing the falls of the
Tennessee River to furnish the power. Plant number one
was completed, but never came into active use until the
Armistice. This plant was designed to produce 60,000
pounds of anhydrous ammonia per day. Plant number
two for the production of cyanamid was completed, but
operation was suspended pending the decision as to the
final disposition of the plant. It was designed to produce
110.000 tons per annum of ammonium nitrate.
SOILS AND FERTILIZERS
Under stress of war, plants were built with an annual
capacity of some 50,000 tons of fixed nitrogen. In 1917
by-product coke ovens produced 80,000 tons of nitrogen
or about 400,000 tons of ammonium suphate.
Our grain crops, potatoes and cotton of the United
States require 6,372,000,000 pounds of nitrogen. Of this
amount not more than 2,000,000 tons are returned by
leguminous crops, imported nitrates, coke ovens and farm
If water power can be harnessed to plants that will pro-
duce commercial nitrogen at a much lower cost than by the
old processes and in unlimited quantities to neglect to pro-
ceed 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.
Phosphoric acid is a compound which contains 43.7%
phosphorus by weight. Nature does not isolate phos-
phorus; it is always combined with something else-usu-
ally lime. The principal commercial sources are phos-
phate 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 suphuric acid, rendering them
soluble, and thus producing acid phosphate. When ren-
dered available it is of equal value, no matter from what
source obtained. Splendid results have been secured by
the use of soft phosphate when used in sufficient quanti-
ties and properly composed or thoroughly inoculated.
It takes 50,000 pounds of water to dissolve one pound
of insoluble phosphoric acid. Of course, this means that
"insoluble" does not mean that which is incapable of be-
ing dissolved, but that it is in combination of two parts
of phosphoric acid with three parts of lime. This form
is found in raw phosphate rock and in bones. The phos-
phorus 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 phosphoric acid is of no value until
it has been dissolved into soil moisture. Even grinding
it to powder won't help much, as it must be in such solu-
tion as to pass through the skin of the fibre rootlets. The
rock must be treated with sulphuric acid, which changes
two of the three parts of lime into gypsum or land plaster
-sulphate of lime-these two parts kill the acid and leave
the phosphoric acid combined with only one part of
lime-and the product is acid phosphate or superphos-
phate. Methods so far used in extracting the phosphate
rock from the soil and in preparing it for fertilizer have
been very wasteful, as commercial acid phosphate made
from 32 per cent rock contains only 16 per cent of phos-
phoric acid. The elaborate washing and screening 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 save this
waste. (See statement at close of this article.)
The combination of both water soluble and reverted
phosphoric acid is the form in commercial fertilizer. It
is a combination of two parts of phosphoric acid and one
part of lime. After soluble phosphoric acid has been in
the soil for a time it undergoes another change-the lime
uniting with the phosphorus becomes "reverted," which
results in a combination of two parts phosphoric acid
with two parts of lime. In this reverted form the phos-
phoric acid is held in the soil, and becomes slowly available.
In making phosphoric 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 condensed in immense lead chambers. Some nitrate
of soda is used in the process. The acid produced is trans-
ferred to an acidulating plant.
Finely ground phosphate rock-pulverized to a fineness
of about 100 per cent through a 60 mesh screen, mixed
in equal parts with sulphuric acide at 52' (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 mixing, 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 transferred to
the mixing plant. Acid phosphate is valuable for the
SOILS AND FERTILIZERS
percentage of phoric 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 pro-
portion 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 delivered to fill orders.
A double super-phosphate plant is being built on the
Alafia River near Tampa. Phosphate will be bought and
then reduced to nearly double strength to meet this de-
mand for greater acid phosphate contents in fertilizer. The
use of this phosphate will affect the formulas.
Materials Furnishing Phosphoric Acid
Material Total Available Insoluble
Acid Phosphate ........ 16 to 17 15 to 17 1 to 2
Dissolved Bone Black...1.7 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
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.
Functions of Phosphorus
Phosphorus is necessary for the development of straw,
seed, and good root systems. It gives stability and vigor
to plants, builds fiber, hardens and matures growth, and
is a ripening element. It is conducive to favorable and
beneficial soil bacteria.
Potassium is one of the elements. The Latin name is
kalium, which is the explanation of why K stands for
potassium in chemistry. The oxide of potassium is a
compound of 78 parts by weight of potassium combined
with sixteen parts by weight of oxygen. The chemist's
symbolic formula is K,0; sulphur of potash KISO4; mu-
riate of potash KC1; sulphate of magnesia MgSO,; chlo-
ride of magnesia MgSI,; chloride of sodium NaCI; sul-
phate of lime CaSo,.
The natural products yielding potash are:
Kainit, calculated to pure potash K20.... 12.8
Carnallit, calculated to pure potash K.O.. 9.0
Sylvinit, calculated to pure potash K,0.. 12.4
The great deposits of potash at Stassfurt, Germany,
were discovered in 1847, and the phosphate rock of South
Carolina in 1868, and later in Florida, Tennessee, Utah,
Wyoming, Montana, Kentucky, Arkansas and Virginia.
It was not till after the Franco-Prussian War that exten-
sive demonstrations of the value of phosphate and potash
were carried on. Germany had potash and no phosphate;
America had phosphate and no potash. The Germans
were exhausting the available phosphorus in the soils, and
we 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 supple-
mented the German 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 seepage
of water to interfere.
The "raw deals" so often handed American dealers pro-
voked extensive explorations to discover deposits, and ex-
periments to discover means of manufacturing it from
other materials containing this element. The lakes of
California, Utah and Nebraska were found to contain an
abundance of potash and certain 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 manufacture 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
SOILS AND FERTILIZERS
out 33,870 short tons; Nebraska, 10 plants, with 34,142
tons output; 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 combina-
tion. Sulphate of potash KSO,, potassium and chlorine,
fifty-fifty, is another which makes muriate of potash-
symbol KC1. A third combination is two combining
weights of potassium, with one of carbon and three of
oxygen-carbonate of potash K2CO,. A fourth combina-
tion is one each of potassium and nitrogen and three of
oxygen. This is nitrate of potash, symbol of KNO3.
Potash is essential for the production of starch, fiber
and the full development of plant and seed.
Bacteria play so important a part in fertility of soil
that they hold an important place in the discussion of
Bacteria are microscopic organisms, microbes, fungi, or
parasites. An organism is either an animal or plant hav-
ing organs performing special functions.
By far the greater percentage of bacteria is vegetable,
both in soil and in animal organisms, but vegetable bac-
teria have no chlorophyl. The bacteria that thrives in
the human organism may be beneficial-as in the process
of digestion-or injurious-as in case of the various dis-
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 ammonifiers, begins to grow as soon as placed
in moist soil. It lives but a short time, and the protein
which has been absorbed is changed into ammonia. When
this group dies other groups take up the ammonia, and
change it into nitrite. When it dies, another group takes
up this nitrite and changes it into nitrate. This last prod-
uct is readily soluble and is dissolved into soil moisture.
The rootlets then take it in along with the soil moisture.
Most organic and some inorganic fertilizers must be
changed by these bacteria before the plant foods become
available. They need warmth, moisture, humus, and air;
too much water excludes the air and too much acid hin-
ders their growth.
Different kinds of bacteria are needed to dissolve dif-
ferent kinds of materials in the soil. Good results have
been secured in some soils through the use of phospho-
germs housed in humus, but with no claim of plant food
content. By housing numerous kinds of bacteria in a
suitable medium, various materials containing plant food
elements are released by their action, which would not be
affected by only one kind of bacteria.
Departments of Agriculture are often asked to give
opinion as to the value of advertised soil bacteria. It is
manifestly impossible to pass judgment on these bacterial
inoculents, the value of which depends upon the number
of virile organisms, adapted to the soil to which they are
to be applied, whose mission is to transform the organic
and mineral elements in the soil so as to render them
available for the plants to be grown.
It is also evident that this kind of soil building agency
must be judged by an entirely different standard from
that of fertilizers. No chemical test would reveal anything
as to the value of these bacteria. The laws regulating the
manufacture and sale of commercial fertilizers do not
touch the subject of soil inoculents. This phase of prac-
tical soil improvement has not been reduced to an accepted
science. When unbiased investigation and adequate dem-
onstration fix a standard for soil inoculation values there
should be legal regulation of the sale of soil bacteria the
same as for commercial fertilizers.
So far no attempts have been made to supply carbon in
available form to plants, an element that constitutes an
average of 40% of the structural parts of plants. During
the carboniferous age, when the atmosphere was sur-
charged with carbon dioxide, vegetation grew so plente-
ously and of such gigantic size as to prepare the material
for the great coal beds of the world. Prof. Riedel has
demonstrated that artificially supplied carbon dioxide
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 rub-
SOILS AND FERTILIZERS
bish, contains chemicals which are absolutely essential;
that the mysterious vitamins are but the sum total of cer-
tain mineral elements in food; and their marvelous effects
but the resultant of the chemical reactions set up by these
mineral elements. May it not be that the carbon of plants
and the ash of foods have not received consideration com-
mensurate with their importance?
Burzelius classes all organic matter in the soil as hu-
mus. Humus is formed by the decay of vegetable mat-
Humus is a generic term applied to a group of sub-
stances, which form the organic matter of the soil.
They range in color from a brownish yellow to a black-
ish brown, or black, and are non-volatile. They are prob-
ably 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 consists of nitrogen and oxygen gases,
vapor, carbonic and nitric acids, and ammonia. Plants
can appropriate these from the air only by the roots or
foliage. Leguminous plants extract nitrogen from the
air by way of the roots through bacterial action in the
nodules on the roots. The air comes in contact with the
roots by the soil being porous, which is aided by culti-
vation. Some soils are closer than others, and some
growths have a tendency to impact the surface with turf-
Bermuda grass, as an example-while other plants have
a loosening effect-as the cocklebur.
Humus performs a useful function in retaining mois-
ture, furnishing a habitat for bacteria, and in holding
potash, soda, lime, and magnesia, and in preventing them
from being washed out of the soil.
Scientists have divided peat into several varieties. The
words peat, muck, humus, marsh, bog, and heath are
often used synonymously, but they are far from being
synonymous. Peat is partially carbonized vegetable mat-
ter. There are various kinds of peat due to the vege-
tation of which it is composed and the conditions un-
der which the formation has taken place, and the age of
the deposit. The materials contributing to peat beds are
many, including both land and aquatic vegetation, such
as ferns, mosses, grasses, roots, weeds, twigs, leaves, shrubs,
etc., found in the presence of water. In an advanced
stage of decomposition, combined with more or less dirt,
shells, etc., it is called muck. Peat may be humus, but
humus is not necessarily peat.
Dr. William Whitney, Chief, Bureau of Soils, Depart-
ment of Agriculture, Washington, D. C., under date of
August 6th, 1920, says:
"It is impossible to make definite statement as to the
availability of the nitrogen contained in peat. Its am-
monia content at any time is low, and is considered as
very slowly available, hence commonly classed as a low-
grade nitrogenous fertilizer, especially when compared
with tankage and dried blood. Recent observations, how-
ever, seem to indicate that the availability is increased by
proper promotion of bacterial growth by inoculation, as
by the use of barnyard manure with the peat. In con-
nection with mineral nitrate, however, it promises to be
of value in supplying a slowly available supply of nitro-
gen after the readily soluble nitrates have been used up."
Organic materials have been extensively used to secure
nitrogen but such sources as cottonseed meal, blood.
tankage, fish-scrap, ground bone, etc., are now used as
feed stuffs and the price is so high as to be almost pro-
hibitive as material for fertilizer. It is often desirable to
derive a part of the nitrogen from an organic source, so
that there will be a supply of nitrogen during the entire
period of growth. The present sources of supply of nitro-
gen-led by the nitrate beds of Chile-are apt to remain
our dependence unless atmospheric nitrogen should be
produced cheaply enough to compete with them.
As a filler for commercial fertilizer, peat, when properly
prepared has no superior, and few equals now in use by
fertilizer manufacturers. It has three distinct points in
its favor over other fillers extensively used: (a) it fur-
nishes a splendid habitat for bacteria; (b) it is an ideal
absorbant of excess ammonia that might escape from
other ammoniates used in the formula, holding them in
22 SOILS AND FERTILIZERS
as available condition as any other nitrates; (c) being
a humus, it has moisture-retaining quality that is much
in its favor, aiding drouthy soils and helping bacterial
The fact that peat properly conditioned before being
dug has an appreciable amount of plant food, is well
established. That this can be made available by bacterial
action, is also beyond question. That fertilizer manu-
facturers should be allowed to claim credit in their brands
for the ammonia in peat when used as a filler would
seem to follow. But there are two very essential things
which must be known before the legitimacy of this claim
can be determined. First, was the peat of proper qual-
ity and in proper condition before being dug? Second,
does the process of treatment after being dug, in prepar-
ing it for the fertilizer trade, damage it as a fertilizing
material? It all depends upon these two things. If the
peat is of good quality, sun-dried, ground, treated bac-
terially with numerous groups of germs, the value is be-
yond question. On the other hand, if the peat is of poor
quality, raw, and undecomposed, is dug and dried to
10% moisture by blast furnace-what have you? As
another proposition, if the peat is all right as to quality,
and is dried by oil blast furnace to 15% moisture, what
is the result ?
Dr. Thomas, of the Earp-Thomas Cultures Corporation,
New York, says, under date of Oct. 14th, 1920: "When
peat of the ligneous variety is dried out with excessive
heat in a short space of time it becomes very insoluble."
The ligneous variety is not the best for fertilizer. Dr.
John N. Hoff, industrial and agricultural chemist, New
York, says under date of Oct. 22nd, 1920: "The effect
of drying peat in direct driers with oil fuel does not
reduce the availability of the ammonia. *
As peat will gasify and burn at about 414 degrees Fahren-
heit, you will realize that the partly dried peat will not
permit final drying much above the average temperature
Under date of December 27, 1920, he writes: "It has
been my observation that the average peat will begin to
gasify between 300 and 400 degrees Farenheit and there-
QUARTERLY BULLETIN 23
fore is likely to burn, which will produce ash with con-
sequent loss of organic matter.'
The heat-drying process is now carried on without the
blast coming in contract with the peat, the degree of dry-
ness is thus made optional. If the peat is rendered too
dry for bacteria to live in it, the inoculating can be done
by the farmer-the easier if he does his own mixing.
SOILS AND FERTILIZERS
IF THE farmer would adopt and practice home mixing
of fertilizer it would save millions of dollars to the pro-
ducers of the country. The farmers of the U. S. use
amount 6,900,000 tons of commercial fertilizer a year-cost-
ing some $200,OC0,000. It is a conservative estimate that a
saving of $8 per ton can be made by home mixing, which
would be approximately $55,000,000 per annum! Not
that fertilizer mixers make exorbitant profits, but they
must charge enough to cover their enormous overhead ex-
penses, to which must be added the freight on the dirt
used as a filler. It is good business, economical, educa-
tional, and a mark of individuality, to buy your own in-
gredients, and do your own compounding. The elements
composing complete fertilizer can be purchased separately.
They should be bought by communities in bulk, and
handled on a cash basis if possible.
The reasons why the majority of farmers buy complete
fertilizers are: (a) the ease with which it can be bought
on time; (b) the desire to shun the work of buying sep-
arately the different elements and mixing them; (c) the
lack of self confidence.
The following articles constitute a fairly good equip-
ment for home-mixing fertilizer:
1-A screen with 3 meshes to the inch, 5 ft. long, and
2 ft. wide.
2-A shovel with square point.
3-An iron rake.
4-A pair of large scales.
5-A tight barn floor, or hard, dry, smooth ground.
6-A Xhavy wooden pestle for crushing big lumps of
The screening should be done first-all lumps crushed
and screened again. Then spread out the most bulky of
the elements in layers-one on another-beginning with
the most bulky constituent. 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 physician who knows nothing of chemistry or phar-
macy might write a prescription that could not be com-
QUARTERLY BULLETIN 25
pounded because of incompatibility of certain chemicals
included, so, in mixing the constituents of a complete fer-
tilizer, 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, and render
it necessary to crush and pulverize before using. Cer-
tain ammoniates contain iron, and if mixed with acid
phosphate will lose a considerable portion of its available
phosphoric acid. Sulphur of ammonia should not be
mixed with Thomas slag and Norwegian nitrate. Cyana-
mid should not be mixed directly with sulphate of am-
monia, but should be mixed as per directions. Basic slag
should not be mixed with sulphate of ammonia, blood,
or tankage, as the lime affects these materials and re-
leases ammonia. Lime should not be mixed with guano
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 ren-
ders the phosphoric acid less soluble-therefore, less
OTLS ANTD FERTILIZERS
HE following table shows how to find the quantity of
Each material necessary to make 1,000 pounds of fer-
tilizer of any desired analysis:
Available Phosphoric Acid. 0
Q Qs from 14% from 16%
S' f S Acid Acid 0
S Phosphate Phosphate .
1 67 lbs. 71 lbs. 63 lbs. 19 lbs.
2% 133 lbs. 143 lbs. 125 lbs. 38 lbs.
3% 200 lbs. 214 lbs. 188 lbs. 58 lbs.
4% 267 lbs. 286 lbs. 250 lbs. 77 lbs.
5% 333 lbs. 357 lbs. 313 lbs. 96 lbs.
6% 400 lbs. 429 lbs. 375 lbs. 115 lbs.
7% 467 lbs. 500 lbs. 438 lbs. 135 lbs.
8% 533 ]bs. 571 lbs. 500 lbs. 154 lbs.
9% 600 lbs. 643 lbs. 563 lbs. 173 lbs.
10% 667 lbs. 714 lbs. 625 lbs. 192 lbs.
If a formula 4-7-5 is wanted, it would mean 267 pounds
of nitrogen, 500 pounds of 14% phosphate, and 96 pounds
of sulphate of potash, making a total of 863 pounds, which
contains the same amount of plant food as 1,000 pounds
of 4-7-5 complete, ready-mixed, commercial fertilizer. To
make out 1,000 pounds add dry loam as "filler."
A. B. Ross has shown that neither in the Pennsylvania
nor Ohio long-time experiments did nitrogen prove profit-
able in fertilizers for rotations containing clover. Those
experiments showed that plants got nitrogen from else-
where than legumes or from commercial fertilizers, as
the amounts taken from the soils exceeded the amount
stored by the legumes and the amount contained in the
Legume bacteria are not the only soil organisms that
can make direct use of nitrogen from the air. A group
known as the azotobacter have this power. Perhaps
there are others. This is mentioned as a suggestion to
those who may get results which differ from what they
had a right to expect from regular methods.
QUARTERLY BULLETIN 27
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 for-
mula 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 results that will follow.
If you use complete fertilizer you might have a formula
Nitrogen ...................... 4%
Available phosphoric acid........ 6%
Potash ........................ 8%
Ammonia ...................... 5%
Phosphoric Acid ................ 8%
Potash ......................... 5%
And use from 1,000 to 1,500 pounds per acre. Or if
you do your own mixing, the formula might be:
Nitrate of soda ................ 320
Acid 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 300 additional pounds
of loam should be added to secure a satisfactory mechanical
condition for the fertilizer.
Ammonia ...................... 4%
Available phosphoric acid........ 6%
Available potash ................ 8%
Six to eight hundred pounds per acre, applied at time
SOILS AND FERTILIZERS
Available nitrogen .............. 5%
Available phosphoric acid ........ 4%
Available potash ................ .
Kainit or muriate of potash should be avoided, as the
chlorine militates against burning well in cigars. The
sulphate form is preferred. Per acre, from 1000 to 1500
pounds, preferably given in three equal dressings, just
before planting and at time of first hoeing and, last, from
two to three weeks later.
Fifty bushels of corn per acre takes from the soil 67
pounds of nitrogen, 31 of phosphoric acid, and 80 pounds
Judged by 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%
Available potash ................ 6%
Cotton is "'easy" on land, but the clean cultivation re-
sults 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 land 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 great a
variety of soils as any crop of the Southern States. The
following may be used where the soil is already fairly
Nitrogen ...................... 3%
Available phosphoric acid ....... 8%
Potash ........................ 4%
QUlARTERLY BULLETIN 29
As this plant is a legume andl 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, and 8% phos-
phoric acid, and the amount from 500 to 800 pounds per
acre. However, this is a mere suggestion as it is entirely
dependent on whether or not the soil has either of these
elements in abundance; in some soils, a small per cent. of
nitrogen should be used.
Ammonia ............. ........ 4%
Available phosphoric acid ........ 8%
Potash ........................ 4%
Sugar cane should yield from 25 to 40 tons per acre.
The amount of fertilizer should be from 600 to 800 pounds
Nitrogen ..................... 4%
Available phosphoric acid........ 6%
Actual potash .................. 8%
Amount per acre, 600 to 00 pounds.
Ammonia ..................... 2%
Available phosphoric acid ...... 10%
Potash ..................... 4%
When the land has an organic soil, such as peat, the
nitrogen can be reduced, and the other elements increased.
From 400 to 500 pounds per acre is the correct amount.
Ammonia ...................... 5%
Available phosphoric acid ........ 8%
Potash ............ .... ....... 3%
Apply 400 to 600 pounds per acre.
SOILS AND FERTILIZERS
Nitrogen ...................... 3%
Available phosphoric acid........ 8%
Actual potash .................. 4%
Apply 400 to 600 pounds per acre.
In the clay hill counties of Florida, wheat can be grown,
and the best preparation is to follow a crop of cowpeas
that were sown in July and all turned under at the time
of maturity that would best suit the mowing of hay. The
peas should be sown late for the reason that they vine much
better than when sown early. They can be sown in corn at
the last plowing. Should they mature too early for sowing
wheat, they should be plowed under anyway, and allowed I
to lie till sowing time.
If the vines 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 plow should have
a rolling cutter in front to cut the vines, so that the plow
will not be continually choking. It is impossible to do
much with iron tooth drag in these vines-the teeth will
have to be slanted backward, so as to slide the vines,
that are left uncovered after the land is plowed.
The grain should always be treated for smut before
Clover and grasses for hay or pastures should be fer-
tilized according to the nature of each. Lespedeza is an
excellent legume for general use on dry hills, as pasture,
and, when soil is sufficiently 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 difficult to destroy. Heavy crops of cowpeas,
velvet beans, kudzu, or sugar cane will shade it and kill
it faster than any other treatment. Carpet grass is easily
destroyed and therefore, is to be recommended for lawn-
making, and also for grazing.
Nitrogen ...................... 2%
Phosphoric acid ................ 8%
Potash ........................ 8%
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 com-
mercial 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 car and truck have superseded the horse in
Stable manure should be well worked into the soil be-
fore planting. The nearer planting time manure is ap-
plied, the finer it should be pulverized.
For asparagus, beets, carrots, cauliflower, celery,
cucumbers, egg plants, kale, lettuce, musk-melons, onions,
English peas, peppers, radishes, spinach, squash, and to-
Nitrogen ...................... 5%
Available phosphoric acid........ 7%
Available potash ................ 5%
There is no iron-clad formula and this is given as an
"indicator" 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
conditions best; or if preferred, use some other approxi-
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 per cent.
Apply from 1,500 to 2,000 pounds per acre, and while
the crop is growing top-dress with about 150 to 200
pounds of nitrate of soda per acre. It requires about three
pounds of seed to sow an acre, or one ounce to every 250
feet of drill.
Baskets for shipping can be obtained from the vegetable
crate manufacturers in any section of the State.
32 SOlIs ANID FERTILIZERS
This is one crop which requires plenty of potash fer-
tilizer, and you will find it will pay to broadcast the field
with a ton of kainit, harrowing it in. Next lay the field
off in furrows, the width 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 analyze as follows: Ammonia,
5%; available phosphoric acid, 4%; potash, 9%. Cover
it well and see that you get it well mixed with the soil.
Ammonia ...................... 3%
Available phosphoric acid........ 7%
Potash ....................... 7%
Or, per acre-
Bone meal ..................... 1700
Muriate of potash .............. 300
Or, per acre-
Nitrate of soda .......... 100 pounds
Acid phosphate .......... 400 pounds
Muriate of potash ........ 100 pounds
Cabbage needs a very rich soil. Where stable manure
cannot be secured, 1,000 to 2,000 pounds of fertilizer may
be used in something 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
QUARTERLY BULLETIN 33
Either of the following formulas for commercial fertil-
izer are good for celery, and the one which seems best
adapted to the soil and conditions can be used, or any
other approximately similar:
1. Nitrate of soda .......... 300 pounds
Fish scrap ................800 pounds
Acid phos., 16% .......... 600 pounds
Muriate potash ............300 pounds
Ammonia ..................... 6.9%
Available phosphoric acid........ 5.5%
Potash ........................ 7.2%
2. Nitrate of soda ........... 250 pounds
Dried blood ............... 600 pounds
Acid phos., 13% .......... 850 pounds
Muriate potash ........... 300 pounds
Ammonia ..................... 7.2%
Available phosphoric acid ....... 5.5%
Potash ........................ 7.8%
During the growth of the crop from one to two tons
per acre of the above may be applied between the rows,
and from two to four hundred pounds of nitrate of soda
per acre as a top-dressing in four equal applications at
about four different times.
From 500 to 800 pounds per acre of a fertilizer contain-
ing 10% of potash, 8% of phosphoric acid, and 3% of
nitrogen would be an average application.
SOILS AND FERTILIZERS
The experienced citrus fruit grower has learned by ex-
perience the kind, amount, and frequency of use, of fer-
tilizer for his grove. The newcomer to a citrus section
should consult growers of long experience in his locality.
Nitrogen plays an important part in the production of
new wood and leaf growth. Excess of nitrogen produces
die-back, which causes the bark to become thick skinned
and puffy. Phosphorus is necessary for the proper de-
velopment of the fruit. Sulphate of potassium is usually
preferable to the muriate as the latter sometimes has an
injurious effect on citrus trees.
Use from one to three pounds per tree for young trees,
according to age, of
N itrogen ...................... 5%
Phosphorus .................... 5%
Potash ........................ 3%
Apply in early spring, mid-summer, and in September.
Increase this about a pound a year until the trees are
five or six years old, and begin to bear commercial crops.
Then use three applications per year with,
Nitrogen ...................... 4%
Available phosphoric acid ....... 8%
Potash ....................... 4%
Apply in early spring, and midsummer. The fall ap-
plication should be between November 15th and Decem-
ber 15th with the nitrogen reduced to 3% without chang-
ing the other materials.
Trees well bearing from ten years old up should re-
ceive from 15 to 30 pounds per year. Older and heavy-
bearing trees receive from 30 to 75 pounds of fertilizer
per annum where no green crops are turned under, and
unless the trees have a great distance between them green
crops cannot be successfully grown.
Judging by the elements taken from the soil by a citrus
grove the formula of chemical manures per acre of orange
trees, will be:
Nitrate of soda ........... 560 pounds
Superphosphate of lime (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 chem-
ical analysis will show, or to correct acidity, as the litmus
paper test will indicate, apply lime carbonate or hydrate.
A Word About Formulas
There is no universal standard in designating the in-
gredients of complete fertilizers by numerals in a certain
order. In other words, a formula-7-5-8-may mean that
the seven stands for phosphoric acid or it may stand
for nitrogen. It seems that all agree in placing potash
last, but there is no agreement as to which comes first,
nitrogen or phosphorus. In alphabetical order nitrogen
or ammonia would come first, and in a great deal of litera-
ture on the subject that is the order in which they are
mentioned. The fertilizer tags of Florida place phosphoric
acid first, which means that a numerical formula would
mean that the first number stands for phosphoric acid,
the second for ammonia or nitrogen and the third for
With this understanding a formula-8-5-3--means that
100 pounds of complete fertilizer contains eight pounds
of phosphoric acid, five pounds of nitrogen or ammonia
and three pounds of potash.
As a ton is two thousand pounds it contains twenty
times as much of each fertilizing ingredient as a hun-
dred pounds of the fertilizer contains.
To ascertain the number of pounds of each ingredient
in a ton of mixed fertilizer:
Multiply the per cent required by 20.
For instance: In the above formula, 8 multiplied by 20
equals 160; 5 multiplied by 20 equals 100; and 3 multi-
plied by 20 equals 60. Therefore one ton of this mixture
Phosphoric acid .................. 160 pounds
Nitrogen ........................ 100 pounds
Potash ........................... 60 pounds
The remainder of the weight is extraneous matter.
SOILS AND FERTILIZERS
To find the quantity of an ingredient needed to supply
the percent required:
Divide the number of pounds of the ingredient in a ton
by the number of pounds of that ingredient in a hundred
pounds of the material containing it. The result will be
the number of pounds of raw material used to give the
percentage desired in the formula.
If we use acid phosphate containing 16 per cent of
available phosphoric acid, to find the quantity of raw ma-
terial needed to supply the per cent of the ingredient
required we must divide the number of pounds required
in a ton by the 16.
If cotton seed meal is used to obtain the nitrogen the
number of pounds required in a ton must be divided by
6.18, as that is the per cent of nitrogen in a hundred
pounds of the meal.
If we use muriate 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 muriate, 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 avail-
able nitrogen the per cent thus added may 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 illustration the use of peat would lessen
the amount of cotton seed meal, which, in turn, would
lessen the amount of potash furnished by the meal. How-
ever it is not necessary to split hairs over such small dis-
crepancies in proportion. The rules for calculation here-
with 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 materials
which he wishes to use in certain proportions and wants
to know the 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 contains eight times 6.18, or 50 pounds of nitrogen.
QUARTERLY BULLETIN 37
Two hundred pounds of kainit at 12.5 pounds per hun-
dred 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,
"Converting" elements into equivalents:
To illustrate: Ammonia contains 82 per cent of nitro-
gen. Therefore to "convert" per cent of ammonia into
nitrogen multiply by 0.824.
To "convert" per cent of nitrogen into equivalent in
ammonia multiply by 1.214.
Three per cent ammonia multiplied by 0.824 equals 2.47
per cent nitrogen.
Two per cent nitrogen multiplied by 1.2214 equals 2.44
per cent ammonia.
To convert ammonia into protein multiply by 5.15;
nitrate of soda into nitrogen multiply by 0.1647; nitrogen
into protein multiply by 6.25; muriate of potash into
actual potash multiply by 0.632; actual potash into mu-
riate multiply by 1.583; sulphate of potash into actual
potash multiply by 0.541; actual potash into sulphate
of potash multiply by 1.85; nitrate of potash into nitro-
gen multiply by 0.139; carbonate of potash into actual
potash multiply by 0.681; actual potash into carbonate
of potash multiply by 1.466; chlorine into kainit multiply
potash (KO0) by 2.33.
In calculating values you simply take the number of
pounds of 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 each for phosphoric acid and potash
and 18 cents for nitrogen. But 16% available phos-
phoric acid was worth $28.00 a ton purchased for cash in
ton lots at Florida seaports; sulphate of potash, $180;
nitrate of potash, $130.00; sulphate of ammonia, $137.00.
SOILS AND FERTILIZERS
Fertilizer prescriptions are at best founded on conclu-
sions drawn from generalization rather than from positive
knowledge. The chemical composition of the soil and its
mechanical condition should be known but rarely is. The
average composition of the crop to be grown, and the
relative amounts of the three principal elements-nitro-
gen, 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 leguminous.
Whether lands are sand, clay, hill, bottom, drained or
wet, been in pasture or cultivated, plowed deep or shal-
low, crops rotated or not, etc., these items should be
known; the results of past experience in fertilizing land
under consideration; yellow foliage indicating lack of
nitrogen; shedding of fruit indicating need of potash.
Where flavor is an item, potash should be used in the sul-
phate form. With pineapples and tobacco carbonate 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 course. They should also state the kind of materials
used to make up the filler and the percentage of each ma-
terial used, and pounds of available plant food per hun-
dred. Protein, fat, sugar, starch, etc., are animal food
terms and do not belong in fertilizer formulas.
QUARTERLY BULLETIN 39
Regulation No. 8
Sa) The tag prescribed by law for commercial fertiliz-
er is as follows; no other statement shall appear on the
Form of Tag
40 SOILS AND FERTILIZERS
(b) TOTAL AVAILABLE PLANT FOOD shall be the
sum of the available Ammonia, available Phosphoric Acid,
and water-soluble Potash.
(c) All guaranteed analysis of complete fertilizer or fer-
tilizer material shall comply with the foregoing form, on
and after January 1, 1926.
(d) All manufacturers, agents or distributors of com-
plete fertilizer or fertilizer materials must file their guar-
anteed analysis with the Commissioner of Agriculture in
conformity with Chapter 10128, Acts of 1925.
Regulation No. 9
Methods of Analysis of Commercial Fertilizer to be used
by the Chemical Division and referee chemists after Jan-
uary 1, 1926.
TIE METHODS FOR DETERMINING AVAIL-
ABLE AND INSOLUBLE AMMONIA and available and
Insoluble Phosphoric Acid shall be those of the Official
Methods of the Association of Official Agricultural Chem-
ists, as revised to July 1, 1924.
(a) TOTAL NITROGEN-Kjeldhal Method modi-
fied to include nitrogen of nitrates (official) as found
on page 8, No. 25, and page 9, Nos. 26 and 27.
(b) WATER-INSOLUBLE ORGANIC NITROGEN
soluble in neutral permanganate (official) Nos. 38 and 39,
page 12 of the Official Methods of the Association of Of-
ficial Agricultural Chemists.
(c) SUBTRACT TIE WATER-INSOLUBLE or-
ganic nitrogen insoluble in neutral permanganate from
the TOTAL NITROGEN for AVAILABLE AMMONIA.
REFEREE CHEMISTS shall use the same methods
in cases of appeal.
USES OF LIME
ORDINARY limestone serves two very important pur-
poses in soil improvement: one is to correct the acidity
of sour soils, and the other is to supply the element
calcium as plant food; and in most soils calcium is
much more deficient than potassium, and even more defi-
cient than phosphorus in many soils. Dolomite not only cor-
rects soil acidity and supplies calcium, but it also supplies
magnesium, another essential element of plant food, the
supply of which is very limited in some soils. Dolomite has
even greater power than the more common limestone in
correcting acidity, 184 pounds of dolomite being equiva-
lent to 200 of calcium carbonate.
In pure form, 56 pounds of quicklime or 74 pounds of
hydrated lime would have the same power to correct soil
acidity as 92 pounds of dolomite or 100 pounds of ordi-
nary limestone. In other words, with ground limestone
at $1.00 a ton or ground dolomite at $1.09, the hydrated
lime would be worth $1.35, and the quicklime $1.79 per
ton, except for one other very important fact; and this
fact is that caustic lime is caustic.
The Kind of Lime to Use
According to the dictionaries, the word caustic means
"capable of destroying the texture of anything by eating
away its substance by chemical action." This definition
well describes the destructive action of caustic lime on
the humus or vegetable matter of the soil; and when the
vegetable matter is destroyed the nitrogen which it con-
tains is liberated and in part dissipated, so that the use
of caustic lime, whether fresh-burned or hydrated, aug-
ments the difficulty of increasing or maintaining the
humus or nitrogenous vegetable matter of the soil. This
problem is already serious enough in Southern agricul-
ture, and if possible we should avoid burning the humus
out of the soil with caustic lime.
Amount of Limestone to Use
While heavier initial applications of ground limestone
may produce even greater benefit, and would certainly
do no harm, four tons per acre are sufficient to give very
SOILS AND FERTILIZERS
satisfactory results, and subsequent applications of two
tons per acre every four years will maintain limestone in
the soil. Heavy applications reduce expenses in perma-
nent systems of soil improvement by saving in labor of
frequent applications and by making use of less finely
In all systems of permanent profitable agriculture,
durability is of greater importance than immediate avail-
ability. If all of an application is "immediately avail-
able," it may be almost immediately lost by leaching with
heavy rains. For high-priced truck crops which must be
hastened for the early market, the grower may need to
take this risk, but in general farming it is far better to
use durable materials which gradually become available
during the growing season, and for several seasons. From
the standpoint of permanent farm profits, there has been
vastly too much emphasis placed upon "availability" and
far too little upon durability in soil improvement.
Lime Is Not a Fertilizer
Lime should not be used as a commercial fertilizer.
Disappointing results usually follow when it is used as
such, according to P. F. Schowengerdt, of the Missouri
College of Agriculture. The application of a few hun-
dred pounds of lime with a grain crop such as corn or
wheat will not be profitable.
Lime should be considered as a "soil corrective." As
such it has a very important use in Missouri. Much of
the soil in the State being acid or sour, lime is required
to "correct" this acidity and make these soils more favor-
able to the growing of clover and other legume crops.
Following the more successful growth of legumes, soil
building is advanced till increases in the grain crops can
Best returns will be secured from lime when it is ap-
plied in amounts sufficient approximately to neutralize
the soil acids. Two tons of raw pulverized limestone per
acre constitute an average application. It is of doubtful
wisdom to apply much smaller amounts than this.
Limestone liberates plant food locked up in the soil,
increases the availability of fertilizers, including potash,
phosphates, nitrogen, and manure, and aids materially in
retaining soil moisture; which is particularly valuable
during dry weather.
The greatest value of lime lies in its power to correct
acid soil conditions. Acid soils have much the same effect
on plant life that a sour stomach has on a person's ability
to digest his food.
Divisions of Terms for Liming Materials
(a). General terms:
"Lime" when it appears in a connection that
clearly indicates the use is a general one.
(b). Group terms:
1 Burnt, or caustic, lime
2 Carbonates of lime
(c). Specific names:
1 Quick, oxide, lump, stone, rock or fresh lime
2 Pulverized quick lime, or pulverized oxide of
3 Hydrated lime
4 Materials, such as air-slaked lime, and vari-
ous by-products by name of process
5 Limestone, according to fineness
6 Lime marls
7 Mussel (oyster) shells
8 Various by-products carbonates of lime by
name of process
Three Groups of Standard Terms
It would seem that three groups of terms need to be
recognized as indicated on the proposed schedule above.
The first of these include general terms that should be
recognized as including any and all the materials in sub-
groups. It is equally important that no attempt be made
to use these general terms in cases where it is desired to
identify a specific material.
The second division includes two groups of materials
that correspond to fundamental chemical differences, car-
bonate properties and caustic properties. These vitally
touch the use and effects of the materials. There has been
SOILS AND FERTILIZERS
some objection to the use of the word "caustic" and for
that reason the words "burnt lime" afford a more satis-
factory synonym for these materials. In the third division
the group terms are those specifically applicable to particu-
lar materials and need never be confused. Conformity to
this terminology will aid in the public understanding of
the use of lime.
Benefits from Liming
Many benefits accrue from the use of lime and make
its use profitable. Among these may be included the fol-
1. Only by the presence of lime can the successful
growth of legumes be expected on many soils. This is
possible through the correction of acidity and the establish-
ment of a basic medium which is favorable to the nitrogen-
fixing bacteria associated with legumes. The growth of
legumes is an essential means of maintaining and building
up the fertility of the soil through the addition of organic
matter and nitrogen.
2. By neutralizing acids lime encourages the decay of
organic matter with its attendant benefits.
3. Liming aids in the formation of available nitrates
from the nitrogen derived from soil organic matter by
bacterial. Farm manure, crop residues and green manures
are thus made to yield their nitrogen more promptly.
4. Calcium and magnesium are essential plant nutri-
ents, and application of lime to the soil may perform that
function. However, lime is not ordinarily regarded as a
fertilizer, since its function in correcting soil acidity prob-
ably overshadows its effect as a nutrient.
5. It is responsible, too, for the release of appreciable
amounts of insoluble phosphorus compounds in soils which
are rich in insoluble phosphates.
6. The tilth of heavy soils can be improved by the use
of lime. In consequence, nitrate formation is promoted
by a freer circulation of air; and the storage and subse-
quent movement of water is better regulated.
7. Certain fine and medium grained soils are inclined
to run together and crust after heavy rains. Such a con-
dition restricts air supply and retards plant growth. Granu-
lation by lime fortifies a soil against such damage.
8. The superior tilling qualities of a granulated soil
make tillage operations more effective and at the same
time less costly.
9. Liming may hasten the maturity of certain crops
by making soil conditions more favorably for their steady
10. It may also be helpful in preventing the erosion
of lands by virtue of inducing a more porous soil and by
reason of correcting acidity, which makes possible a better
growth of sensitive legumes and grasses, the roots and tops
of which are of no small protection against "washing."
Relation of Plants to Soil Acidity
Some plants grow best in an alkaline soil, some in a
neutral soil, and some in acid soils. Furthermore, each
plant seems to have a certain range of soil reaction on
which it will grow. Red clover and mangel beets, for
example, prefer a distinctly alkaline soil and will not grow
on a soil that is very acid. Oats and potatoes seem to
grow well both on soils that are acid and on those that are
alkaline, and probably do best on soils that are near the
neutral condition. On the other hand, the chestnut tree,
the arbutus, and the blueberry require a moderately acid
soil for their successful growth.
SOILS AND FERTILIZERS
We Learn How to Speed the Work of Priceless Soil
By J. SIDNEY CATES, in The Country Gentleman
'iHE good old word "tilth" as applied to soil needs to
come back into general use. It serves to denote a con-
dition of the land and to set forth an ideal of manage-
ment covered by no other term. During the past generation
both biological and chemical sciences have piled up a mass
of information about the soil, and we are beginning to see
the seemingly inert land we walk over and plow in a new
and romantic light.
Keeping it in fettle is something more than the mere
mechanical task of tillage. In fact, the German word for
tilth, gare, is frequently interpreted as meaning fermenta-
tion. It is an interpretation which fits well, for we know
that a good soil is seething with life, pouring forth invisible
gases that leaven it and fine its texture, and leaving be-
hind by-products ideal for plant food. And, ranked as a
chemical laboratory, no learned doctor with his retorts and
bottle-arrayed walls can duplicate or even approximate the
reactions that Nature, working through this life-filled
upper eight inches of a plowed field, carries on night and
day uninterruptedly year after year.
These midget chemists of the land, the bacteria, play the
major role in promoting tilth. In teeming hordes they are
present. They often number more than three billion to
the ounce of soil, and under many conditions alge, molds
and protozoa are equally abundant. The total microscopic
life in an acre of land has been calculated as weighing from
500 to 700 pounds, or approximately the equivalent weight
of livestock that a good pasture will carry. And while
the role that this soil life plays is so complex that it will
probably take more generations of close study before the
full activities going on under the surface of the land are
clearly understood, a few broadly fundamental facts have
already been brought to light.
In the first place, it is clear that soil life is necessary for
true fertility-that is, for power of the land to produce
crops. Not only must this germ life be abundant, but it
must be in a healthy well-nourished state and actively
multiplying, in order that the land may have that loose,
crumbly texture taken as a good omen by the eye of every
Tireless Nitrogen Gatherers
Bacteria, for the most part, subsist on organic matter
in the land. Not only does this teeming soil life break
down added vegetable matter, producing or setting free
mineral salts upon which crops directly feed, but one large
group of soil bacteria functions in the nitrogen-gathering
role probably with as great benefit to soil fertility and
tilth as the better-known nitrogen-fixing germs which grow
on the roots of leguminous plants. A legume crop will con-
tain from 100 to 200 pounds of nitrogen. Probably half
of this comes from nitrogen compounds already in the
land, and the remainder is gathered in from the air by the
aid of nitrogen-fixing germs with which the roots of the
legume are inoculated. We hear much of the importance
of having a legume crop in the rotation. We, hear, how-
ever, but little of the other and greater source of nitrogen
supply in our soil. This other great source is through the
action of bacteria feeding on the dead vegetable matter.
One leading American bacteriologist recently gave me the
estimate that the quantity of nitrogen fixed in soils by
these independent organisms varies from ten to forty
pounds a year an acre. The larger quantity is often to be
found when a plentiful food supply in the form of organic
matter is made available for them to feed upon. These
germs, while fixing annually a smaller quantity of nitrogen
than is gathered in by a legume crop, more than over-
come this handicap through working all the time, and in all
soils, while the legume rarely ever occupies the land as
much as half the time, and usually only one year in the
four-year rotation; and on many farms is not planted at
It has been the experience of mankind for ages back that
vegetable matter turned into the land made it more pro-
ductive. Since the establishment of our own experi-
mental institutions in this country, an abundance of data
has been accumulated, all showing that organic mat-
ter in the land takes the leading upbuilding part.
But now we know that this organic matter is not
used directly by crops; that it must first be broken down
SOILS AND FERTILIZERS
by soil life. With the exception of nitrate, acid phosphate
and the various potash salts, plants take no fertilizers in
the form we put into the soil. Not only are bacteria nec-
essary in preparing the raw food we supply in form for
plants to consume, which is a mineral form, but the bacteria
themselves, thus fed, gather vast quantities of nitrogen,
the most expensive of all plant foods. The quantity they
gather seems to bear a close relation to the provisions we
make for their food supply. And this conclusion puts the
problem of the tilth of the land in a new light.
Soil life also shows considerable preference in its diet.
It has long been observed that stable manure in many cases
exerts an effect on crop growth out of all proportion to
the plant food it contains as shown by analysis, and that
the same is true of green matter turned into the land in
the early spring. Studies during recent years have shown
that both these substances make wonderful feeding for the
bacterial flora of the soil, causing a sharp upward spurt
in soil-life activity. In pot experiments, a small quantity
of green matter chopped into one soil pot almost always
caused a sharp leaping ahead of the plant it grew as com-
pared with another plant in a similar pot where the soil
was not so treated. It seems to me there is considerable
evidence to justify us in planning cropping systems in
so far as soil maintenance goes, with a view to feeding
plenty of vegetable matter to the soil bacteria, and if a
goodly quantity of this bacteria food we offer is in a
succulent green state, there is plenty of evidence that it
will be all the more relished.
in the Middle West, farmers who turn a sweet-clover
sod very early in the spring before much growth has
been attained, yet while this growth is in a very succu-
lent stage, note that a fat yield of corn follows. Over
in the Connecticut Valley in New England, farmers have
found that it pays to sow timothy between rows of culti-
vated crops in late summer, and to turn this feeble early
spring growth in time to plant another tillage crop the
next year. In New Jersey the truckers turn a winter
cover crop of rye or vetch or alsike clover before it has
attained enough growth to make an impressive showing.
Yet they have found that this means a saving of fertilizer
bills, and a great boost to the tillage crop which follows.
A small quantity of this succulent material greatly stimu-
lates soil bacteria. And it is the bacteria which make for
tilth in the land.
We passed through a state of mind not so long back
when common observation of farmers, out of line with
some half-understood but supposedly wholly elucidated
theory, was ranked as mere superstition or old women's
tales. Science is today more tolerant and less cocksure
than it used to be. In fact, some of the hypotheses on
which learned men are now working seem more strange
and we rd than what were ranked as superstitions of by-
gone times. Our thought with reference to soil problems
seems itself to be in a healthy state of ferment.
One bacteriologist, in discussing the role of this micro-
scopic life in promoting tilth in soils, called what we know
as poor land "raw," and likened it unto a green cheese,
both of which he said were prepared for real food, one
for humans by the ripening action of enzymes in the milk
and the other for plants by the ripening action of bacterial
New Light on Rotations
Take the case of the explanation of why rotation of
crops is beneficial. The farmer has long known that by
rotation he could keep the land in better tilth, and that
he could keep both himself and the land more regularly
employed. Not long back, rotations were claimed by scient-
ists to keep up yields better than single cropping through
the fact that different kinds of plants remove plant-food
elements from the soil in different proportions, and that
by changing from one crop to another, the soil supply of
plant food was kept more evenly balanced. This point
of view has long since been pretty well abandoned. Then
for a long while we looked upon rotations as being a means
of keeping up fertility through growing periodically a sod
or legume crop to boost the vegetable matter and nitrogen
supply, and beyond this shifting crops is a means of
keeping both land and labor the more continuously em-
Now we are finding that different crops act on the soil
bacteria in different ways. Legumes aside from being
host plants to what we term symbiotic bacteria growing
on their roots, the bacteria being fed carbohydrates by
the plants and in turn feeding the plants with nitrogenous
material-aside from this well-known fact, it has been
50 SOILS AND FERTILIZERS
proved that legume crops specially favor the development
of bacteria in general in the soil. Fortunately most of
our cultivated crops seem friendly toward soil bacteria.
Some few, notably mustard, have been observed to be dis-
tinctly detrimental to the nitrifying and other desirable
Wheat does not seem to leave the bacterial flora of the
soil in as good condition as corn or potatoes. European
agriculture has pretty well settled down on a system which
does not include the growing of wheat oftener than once
in two years. Fortunate it is that corn does not seem to
have a very detrimental effect on soil bacteria.
SULPHUR FERTILIZATION TO HELP SAVE
AMERICAN SOIL FERTILITY
By COURTENAY DeKALB,* in Manufacturers Record
HE shortage of fertilizers not only caused an almost
prohibitive increase in their price, but it became fi-
nancially impossible for a large proportion of our
farmers to purchase fertilizer at all. Everywhere it was
used in greatly reduced amount. Although American agri-
culturists are far behind the progressive farmers of Europe
in fertilization, the curtailment of our customary supplies
at a critical moment, when men were keenly awakened to
the need of superior effort to produce foods, threatened to
precipitate a national calamity. An alarming decrease in
the yield per acre was seen throughout all those portions
of the country where the farmers had become educated to
use fertilizers. At the same time the Food Administra-
tion posted in every conspicuous spot throughout the land
the impressive slogan: "Food Will Win the War." Thus
was the menace of serious weakening in our power to fight
It was during this period of need that the writer, re-
sponding to the national call for means to increase the
food supply, directed attention to the remarkable results
that had been obtained in France and in other countries
by means of sulphur fertilization. This method of aug-
menting the yield had been tested by a number of the
United States Experiment Stations. Extraordinary bene-
fits had been reported from long-continued tests in Ore-
gon, Utah, New Jersey, Kentucky, and elsewhere, but no
wide public notice had been taken of the fact. The masses
do not read the wonderful bulletins issued by the Agri-
cultural Experiment Stations; the facts recorded mainly
reach the people at second hand through the agricultural
*Mr. Courtenay De Kalb, distinguished engineer, chemist and
technical expert, is particularly well qualified to discuss this
subject. He has had practical experience in his professional
capacity as an investigator in various places in this and other
countries, and has been an educator and voluminous writer on
scientific matters. He is an honorary member of the Geo-
graphical Society of Peru, a irember of the American Institute
of Mining and Metallurgical Engineers and of the American
SOILS AND FERTILIZERS
papers, or tardily, in isolated cases, through observation of
the results obtained by progressive neighbors who are fully
awake to the great service the United States Department
of Agriculture is doing through its systematic investiga-
tions in scientific agronomy, and who read the literature
issued from the Bureaus in Washington and the co-ordi-
nated Experiment Stations in the several States.
A first article published in the Manufacturers Record,
showing enormous increases in yield-100 per cent to 1000
per cent in alfalfa (Bull. 163, Oregon Agricultural Ex-
periment Station), 300 per cent in peas (P. J. O'Gara.
A. S. & R. Agricultural Experiment Station, Salt Lake,
Utah), 40 per cent in kaffir corn, and the like-aroused
such keen interest that it proved necessary to follow it by
a second article in which the reasons for the efficacious
results obtained with sulphur applied as a fertilizer were
set forth in detail. These explanations were later con-
firmed by Dr. O'Gara and others in articles also appear-
ing in the Manufacturers Record.
At a time of dire national need it meant a great deal
to be shown that it had been proved to be possible to in-
crease the yield of cereals 25 per cent to 100 per cent, even
if limited to'somewhat restricted areas to which sulphur
fertilizer could be distributed economically. It was a vi-
tal matter to be able to double and treble the acre-yield of
beans and peas at a period when the Government was con-
tracting for shiploads of beans in the Far East, and was
anxious lest the bean-line to the soldiers in training camps
and on the plains of France should be interrupted. More-
over, while the importations of Rio Tinto pyrite, formerly
our main dependence as a raw material for making sul-
phuric acid with which to prepare acid phosphate, had
been reduced for want of bottoms to a few thousand tons
per annum, and while nearly the total supply of domestic
sulphur melted from the deep wells of the Union, Free-
port and Texas Gulf companies on the Gulf of Mexico was
required to make acid for explosive manufacture, it was
pointed out that Nature had provided superficial deposits
in Culberson County, Texas, in Wyoming, in Utah, in Ne-
vada, and elsewhere in the West, where elemental sulphur
was associated with gypsum and lime and lesser amounts
of magnesia, making an ideal material to function as a
As a result of these and other public announcements, sul-
phur fertilizer is taking a position as one of the most use-
ful substances for increasing the yield of many crops.
Sulphur companies East and West are distributing it in
varied forms, and the agricultural experiment stations in
at least twenty States are investigating the extent of its
adaptability and a large number have already made fa-
vorable reports. In some of the States, with intent on the
part of legislators to protect the farmer against the adul-
teration of fertilizers, laws had been passed that limited
the sale of fertilizers to those products that contained only
a few of the necessary plant foods. Changes in these laws
are being demanded. Intelligent farmers will not tolerate
laws on the statute books that put a bar to progress.
It is curious to read statutory definitions of what plant
foods are, and to find that only three are mentioned. One
of America's greatest agricultural chemists, Dr. Charles
H. MacDowell, President of the Armour Fertilizer Works,
Chicago, and President of the National Fertilizer Associa-
tion, in an address before the Chicago Section of the
American Chemical Society, September 23, 1921, said:
"For a long time it has been considered that these three
elements, nitrogen, phosphorus, and potassium, were the
only plant-foods necessary to supply ordinary soil. Re-
cent years have brought about some change in this belief.
Certain crops seem to demand some other element that is
ordinarily not abundant in all soils. For instance, only
within the last few weeks it seems to have been definitely
proven that the tobacco plant must have a certain amount
of magnesia in its food-supply in order that it may prop-
erly cure. It is claimed that the super-excellence of the
Hawaiian pineapple is due to the manganese present in
those soils. Are we, then, to believe that only these two
plants are peculiarly susceptible to such conditions? Can
we safely assume that every plant has a similar necessity?
Most of the experiment stations of the country are now
studying the effect of sulphur, both elemental and in
compounds, on various crops. Oregon has shown surpris-
ing results on legumes with sulphates (chiefly with sul-
phur fertilizer, now standard practice among alfalfa grow-
ers in Oregon-C. DeK.). New Jersey applies elemental
sulphur for reaction within the soil itself. What a re-
search-field is open to the agriculturist and to the chemist!
SOILS AND FERTILIZERS
This further leads us to the question of the balanced ra-
tion for plants. *
"These problems must be solved if this country of ours
is to maintain itself in the front rank or as a leader of the
nations of the world. Our tendency has been recently to
commercialize our science. Our agricultural science must
be national, must be removed from politics and commercial
influences. We must realize that, as a nation, we must
get more from our soil. Our scientists must solve these
vital questions in the near future or the coming genera-
tions will find their food-supply restricted either as to
quantity or variety to a point where degeneration of the
race sets in and conditions similar to those now obtaining
in the Orient will be in effect here."
A similar lesson was enforced by Dr. W. S. Landis in
an address at a joint meeting of the Honorary Scholastic
Societies at Columbia University, New York, on Decem-
ber 7, 1921. He shows that the problem is world-wide,
but that America, curiously enough, is one of the most
backward of all countries in practical agriculture. This
is a matter of grave moment when we consider that already
we have begun to import staple foods-meat, potatoes,
even grains-in large amounts, and that more than half
our total population is now crowded into cities, and from
a food standpoint is non-productive. As a nation we have
persisted in the primitive viewpoint held by the pioneer
when he was subduing a virgin continent. We still have
an incorrigible tendency to cultivate acreage on the grand
scale, instead of striving to increase the output per acre.
We go on as if we still had unlimited areas of soil that
had never been stirred by the plough. Our farmers strain
their finances to buy ever more elaborate and costly im-
plements, but they balk at the purchase of plant-food to
renew the wasting asset of soil fertility.
Says Dr. Landis:
"The higher yields of even the oldest European farms
is largely due to the use of fertilizer, along with more care-
ful and intense cultivation. * But fertilizers are
hardly used in the United States. In 1919 on 359,000,000
acres of cultivated land there was used less than 7,000,000
tons of fertilizer, not counting barnyard manure, or less
than an average of 40 pounds per acre. The most concen-
trated of these fertilizers carried less than 20 per cent of
plant food, and the average of all less than 14 per cent.
Just think: On the average less than 6 pounds of plant-
food is added to the acre of tilled land, and that the wheat
harvested from that same acre (straw excluded) carried
off 34 pounds of plant-foods."
Dr. Landis might have pointed out that the crops har-
vested here and abroad are in direct proportion to the
amount of fertilizer used. The average return from Amer-
ican wheat fields from 1905 to 1913 was 14.6* bushels per
acre. In France it was 20.2 bushels, and the average con-
sumption of fertilizer was 111 pounds per acre; in Ger-
many the yield was 30.9 bushels with an average of 207
pounds of fertilizer; in Great Britain the figures were 33.4
bushels and 244 pounds respectively. Assuming a price
for fertilizer of $40 per ton to the farmer and a selling
price of $1 per bushel for the wheat, the British farmer
wins an extra $18.80 per acre over the American farmer's
average, at an extra cost of $414, giving him a net gain
of $14.66 per acre.
This is but a single instance of the great possibilities
lying before the American farmer which he can utilize
as soon as he is led to realize that, with practically the
same labor, one acre, when he goes about it rightly, will
yield a larger profit than two under his present neglect
of the advantages of fertilization. If this were borne in
upon his consciousness so that he should begin to purchase
the kinds of fertilizer needed in proportion to the amounts
employed by the British farmer, he would call for seven
times as much as is used today, and the capacity of the
existing fertilizer plants would be utterly unable to meet
the demand. Certain it is, the farmer must begin to
utilize fertilizers on a proper scale very soon or he will
be swamped and the nation will become dependent on
foreign countries for food to an alarming extent. We can-
not go on indefinitely removing five times as much plant-
food from our soils as we return to them.
Mr. MacDowell was right in insisting that it is im-
perative to provide growing plants with a balanced ration.
That means not only that a proper amount of available pot-
ash, nitrogen, and phosphorus shall be incorporated into
the soil, but that the lack of sulphur, or lime, or magnesia,
or iron shall be made good, in accordance with the special
requirements of different crops. Dr. Lj. W. Erdnliu of
the Iowa Agricultural Experiment Station, in "Soil
*In 1921 the average had dropped to 12.7 bushels per acre.
SOILS AND FERTILIZERS
Science" for December, 1921 (P. 433), says: "Recently
many soils have been found to be deficient in sulphur,
one of the essential plant-foods, and sulphur requirements
of certain crops are apparently much greater than former-
Sulphur fertilization is specially important for plants
that normally contain large amounts of protein, for all
proteins hold sulphur as an essential constituent. C. O.
Swanson and R. W. Miller, of the Kansas State Agricul-
tural College ("Soil Science" Vol. III, No. 2, p. 139),
says. "That sulphur is an element essential to crop pro-
duction has long been recognized by both botanists and
agronomists. Sulphur is indispensable in the formation
of plant proteins, and because of the intimate connection
of protein compounds with life processes, it probably
serves physiological functions in the formation of com-
pounds which do not contain sulphur." A shortage of
sulphur means lessened crops. This applies with special
emphasis to legumes, including alfalfa, clover, beans and
It is evident that the role of sulphur in the soil is
complex. It has been pointed out (P. E. Brown and II.
W. Johnson, "Soil Science," V. 1, No. 4, p. 339) that
"the total sulphur content, alone, of a soil will not show
the sulphur available for plant-growth. The sulfofying
or sulphate-producing power of the soil must also be ascer-
tained." In other words, there are effects produced upon
the bacterial life in the soil that are of the utmost value,
and the mere presence of sulphates, or the introduction of
sulphates in combination with potash, ammonia, or acid
phosphate, is not equivalent to the bacterial oxidation of
sulphur in the soil in contributing to the healthy growth
of plants. Not only does this action stimulate the sulfo-
fying bacteria, but the ammonifying and the nitrogen-fix-
ing bacteria as well.
The production of sulphuric acid in the soil when free
sulphur is present, both directly and by indirect reactions,
liberates potash and phosphorus in available form from
the soil particles. It is on account of these reactions that,
as two of our ablest agronomists have said, "for permanent
soil fertility, the sulphur supply for crops must be con-
sidered" (Brown and Johnson, loc. cit.). It is also note-
worthy that, although small amounts of sulphur are
brought down in the rains (normally about 7 pounds per
QUARTERLY BULLETIN 57
acre yearly, and slightly more in regions where large
quantities of coal are burned in manufacturing) the losses
by drainage have been found to exceed in most cases the
sulphur derived from this source, and the amount re-
moved from the soil by a large number of common farm
crops is very much greater. For example, a normal crop
of sugar beets removes 12 pounds of sulphur, alfalfa 26
pounds, and cabbage 40 pounds.
There is no doubt that sulphur is of the greatest value
in fertilization to stimulate a healthy growth of plants, to
provide them with an essential plant-food, and to render
available the plant-food constituents in the soil. In this
respect its function is unique. The American farmer must
not only work his acres but make his acres work, and
he must make them work to the limit. This can be done
only by strong fertilizer, and .he must bear in mind the
importance of maintaining the balanced ration. IIe must
provide all the foods needed, and not omit any that will
insure healthy crops and maximum returns.
SOILS AND FERTILIZERS
SOIL ANALYSIS NO GUIDE TO FERTILIZATION
By E. J. KINNEY, in Southern Agriculturalist
ARMERS frequently ask their experiment station to
analyze a sample of soil from a certain field and on the
basis of the analysis to recommend the exact fertilizer
needed to produce a certain crop. They are often very
much disappointed, and sometimes a bit angry, because
the station refuses to make such recommendations.
Soil analyses have been of considerable value to agri-
culture. They have given us a wide knowledge of the
character of the various soils of the country, and have
made it possible to make general recommendations in re-
gard to the necessary treatment of these soils in order to
maintain permanent fertility. As a guide to fertilization
in particular instances, however, they have little value.
A chemical analysis gives us fairly accurate data on the
total amount of plant food in the soil. It tells us whether
or not the supply of phosphate or potash is sufficient to
produce good crops under good systems of management
without buying commercial forms of these mineral ele-
ments of plant food. It also tells us whether the soil is
acid or alkaline, but it does not show us the crop-produc-
ing capacity of a certain soil at a particular time.
The samples used by a chemist are of necessity so small
that the inaccuracy in a very careful analysis, by a skilful
chemist, may be greater than the amount of plant food
contained in a very heavy application of commercial plant
food. A field that has been reduced to temporary low
productive power by heavy cropping or bad farming may
show as much total plant food as another field capable
of producing a big crop. For example, we may raise five
crops of corn in succession on a naturally good piece of
land. At the end of that time the ability of that field to
produce corn will be much lessened. Yet a chemical
analysis may show practically no difference in the amount
of plant food present between this field and one lying
beside it that has been in pasture for five years.
This is hard to believe; but such are the present limi-
tations of the chemical analysis. The weight of an applica-
tion of fertilizer is so small in comparison with the great
weight of the surface foot of an acre of land (about 4,000,-
000 pounds) that the use of a ton per acre may be unde-
tected in an analysis. If in addition to the analysis, how-
ever, the soil expert has a good knowledge of how the land
has been cropped and treated, he can usually make recom-
mendations for fertilizer treatment that will meet the re-
quirements fairly well.
Take, for example, the question of fertilization for dark
tobacco on the lands of Western Kentucky. A chemical
analysis shows these soils to be rather low in phosphate,
but rich in potash. If they are handled well-that is, if
crops are rotated, legumes grown, some manure used and
possibly lime, the soil expert may recommend the use of a
phosphate fertilizer only. He knows that the phosphate
supply is too small to give maximum yields even under the
best system of soil management. Potash, on the other
hand, will become available in sufficient amounts for all
requirements on well managed soils; and if legumes are
grown often in the rotation, the nitrogen supply may be
adequate. In case of tobacco, however, which gives rela-
tively large returns per acre, a liberal supply of nitrogen
is needed for best results and he may recommend the use
of some nitrogenous material. If the land has been crop-
ped fairly hard, it usually pays to use a complete fertilizer.
The expert will recommend the amounts to apply almost
wholly on the cropping practices of the past.
SOILS AND FERTILIZERS
SAVING MONEY IN PURCHASING FERTILIZER
By R. W. RUPRECHT, in The Florida Grower
VERYBODY is interested in ways to save money;
none more so than the farmer who must make every
dollar count if he expects to come out ahead of the
game. One of the ways a farmer can save money is in the
careful purchase of fertilizers. There are three different
and yet closely related ways by which you can cut down
your fertilizer expense. These are as follows:
1. Pay cash.
2. Buy co-operatively.
3. Buy high-grade fertilizers only.
The idea of paying cash for what you buy is gradually
spreading all over the country and into all lines of busi-
ness. The cash and carry grocery stores, I believe, were
the first ones to show the savings that could be made by
getting away from a credit business. It is only within
the last two or three years that the fertilizer trade has
made a special effort to get its business on a cash basis.
A few years ago over 80 per cent of the fertilizer trade
was on a credit or time basis. Just what the figures are
today I cannot say but judging from reports I have had
from several fertilizer companies the percentage has been
All fertilizer companies will give a substantial discount
if you pay cash for your fertilizer. Some companies are
offering as much as 13 per cent discount if you send them
a check with your order, or 10 per cent for cash for 10
days from invoice. Others give discounts varying from 5
to 8 per cent. Have you ever figured out how much you
would save if you took advantage of these discounts? Let
us take an actual case and figure out the saving.
Discounts Offer Big Savings
I have a price list showing a price of $42 per ton for
a 5-7-5 fertilizer. Suppose you are buying 10 tons of this
formula. This would make a total of $420. However, if
you send a check along with your order you would only
have to send them $378.00, making a saving of $42, which
is 10 per cent of $420.00. Quite worth while, is it not
Nor is this all you would save. If you paid six months
QUARTERLY BULLETIN 61
after date of your invoice you would get a bill for $420,
plus 8 per cent interest on this amount for 6 months, or
$16.80, so you would would be paying $436, instead of
$378, the cash price. I know that for a good many far-
mers it would be pretty hard to lay their hands or four or
five hundred dollars to pay their fertilizer bill. Those of
you who cannot find the money should go to your banker
and borrow the money from him. True, you will have to
pay him 8 per cent interest on the money but you will still
be saving the $42.
We now come to the third class of farmers-those to
whom the local banker will not lend the money. What I
am going to say may sound cold-blooded but it is the
truth nevertheless. If your own banker who knows you
and your farm and your farming methods does not feel
that he can lend you money safely, the fertilizer com-
panies have no business to sell fertilizer to you on time.
One of the chief, if not the chief reason, for the hard
times that the fertilizer industry has just been through
was due to this very practice, namely of extending credit
where it had no business doing so.
Do you not realize that all of you who pay your fer-
tilizer bill are also paying the bill of the dead beat and
crook who orders his fertilizer but never intends to pay
for it? Some people would have you believe that all
farmers are honest. But farmers as a class are just like
other groups of people, be they clerks or college professors
or what not. Some will do wrong.
Probably all of you are familiar with the cash and carry
grocery store and know that they sell goods at a lower
price than the old time grocer where you went in, ordered
your goods and said "charge it." The cash and carry
stores have to pay just as much for their goods when they
buy from the wholesaler as does the other grocer where
you say charge it. Why can they undersell him then?
Simply because they have no bad bills and no bookkeeping
to do. The very same thing applies to the fertilizer trade.
Even now they allow you a substantial deduction for cash
as I pointed out before, but this will be largely increased
if they ever get to the point where they do nothing but a
SOILS AND FERTILIZERS
Co-operate in Buying
We come now to the second way in which you can save
money in buying your fertilizer: Buy co-operatively. By
buying co-operatively I mean buying through some farm-
ers' organization or just a group of neighbors getting
together and sending their order in as one. The amount
you can save by thus lumping your orders will depend
largely upon the size of your order. Most fertilizer com-
panies will quote you a lower price on a full carload of
one brand of analysis than they will on single ton orders.
A still lower price will be quoted if you can get together
a total of 100 tons, preferably of one analysis. The cut
in price will vary from $4 per ton up. Why can the fer-
tilizer companies afford to give you this extra cut? Sim-
ply because they can save about that much in taking care
of your order. You can readily see, I think, that it takes
less time to look after one large order than a dozen small
less than carload shipments. In many cases the less than
carload shipments have to be hauled to the freight station
while the car loads can be loaded into the cars right from
the bagging machine. Hauling costs money as you all
know, hence the lower prices for goods that do not have
to be hauled. Another saving is made in bagging the
fertilizer. It is considerably cheaper to keep a bagging
machine running on a single formula all day or half a
day than to have to keep changing. Each change means
a certain amount of lost time because you cannot start
bagging a different formula until the machine has been
cleared of the one you have been bagging. This lost time
will vary in different factories but will, I believe, average
pretty close to $5 or $10 per day, maybe more. Another
saving that the fertilizer companies make in handling
orders is in storage charges. It gives them an opportunity
to use up raw material as it is received without going to
the expense of storing it in their warehouse. All these
savings are passed on to farmers when they buy co-opera-
Going now to the third way of saving on your fertilizer
bill: Buy only high analysis goods.
Our last legislature passed a bill which will compel you
to live up to this advice whether you want to or not. The
bill states that no mixed commercial fertilizer sold in the
state shall contain less than 14 units of available plant
food. I am rather glad they did this though it is going
QUARTERLY BULLETIN 63
to make some of the farmers rather disgruntled when they
find they cannot buy their favorite 2-8-2 formula. But
let me show you that in place of grumbling they ought to
give the legislature a vote of thanks.
According to one of the latest price lists, a 2-8-2 fer-
tilizer costs $30.50 per ton. The same price list also con-
tains a fertilizer analyzing 3-9-3 at $35. This would make
a 3-12-3 fertilizer cost about $38. Now let us do a little
figuring. Three tons of the 2-8-2 fertilizer would contain
6 units of nitrogen, 24 of phosphoric acid and 6 of potash,
and at $30.50 per ton would cost you about $91.50. Two
tons of the 3-12-3 formula would give you 6 units of nitro-
gen, 24 of phosphoric acid and 6 of potash, the same as
the 3 tons of 2-8-2 and would cost you at $38 per ton $76.
Subtract $76 from $91.50 and you get $15.50. In other
words, you can get the same amount of plant food in the
two tons of 3-12-3 as you get in three tons of 2-8-2, and
you save $15.50 and the freight on one ton of fertilizer.
After the first of January, 1926, you will be unable to
purchase the 2-8-2 fertilizer. To take its place I would
recommend that you try the 3-9-3 which will, I feel sure,
give you just as good results at a substantial saving. See
how kind the legislature was. It is forcing you to save
The Difference in Fertilizers
Why is it that there is such a big difference in the price
of these two fertilizers? Let us look at a typical formula
for these two analyses and see what we can see:
110 pounds nitrate of soda.
267 pounds cotton seed meal.
1,000 pounds acid phosphate.
84 pounds sulphate of potash.
539 pounds filler.
320 pounds nitrate of soda.
267 pounds cotton seed meal.
1,388 pounds acid phosphate 17 per cent.
125 pounds sulphate of potash.
SOILS AND FERTILIZERS
Fourteen Standard Formulas for Florida
The first column gives the per cent of nitrogen, the
second the per cent of available phosphoric acid and
the third the per cent of potash in the fertilizer.
The crops shown after each formula indicate some
of the crops for which it is best suited, but there may
be other crops for which it is suited. For some soils
or under some conditions some other formula than the
one indicated might give better results. Consult your
county agricultural agent if in doubt as to what for-
mula to use.
3-2-3-General field crops, such as cotton, corn and
4-8-4-Sweet potatoes. Strawberries on rich soil.
5-7-5-5-8-5-General truck crops, particularly
watermelons, cantaloupes and Irish potatoes. Straw-
berries on average soil.
5-5-5-Celery, lettuce and cabbage.
4-8-3-Peas, beans, growing pecan trees, citrus
nursery stock, and young grove trees.
4-8-6-Sweet potatoes, Irish potatoes, tomatoes.
sugar cane, bearing pecans and peaches.
5-7-3-General truck crop or cabbage on clay soils.
3-8-5--Tomatoes on soils rich in organic matter.
Also summer and fall citrus applications.
3-8-8-3-8-10-Citrus fall and winter application.
2-8-10-Citrus fall and winter application on rich
4-8-8-Citrus in spring, tomatoes and strawberries.
6-6-4-General truck and cabbage on poor soil.
In the one case you have a fertilizer containing 500
pounds, or 21/, bags of filler of little or no value to your
plants, yet for which the fertilizer people had to pay. In
the other case you have a fertilizer containing only ma-
terials supplying plant food.
It cost the fertilizer company just as much to mix the
low grade formula as the high grade. All of the operat-
ing expenses are the same for both formulas. As you
are getting six more units of plant food in the high grade
formulas your cost per unit is less. For example, say it
cost $3.50 per ton to mix these goods. In the case of the
2-8-2 this means about 30 cents for each unit of plant food.
In the case of the 3-12-3 it means only 20 cents per unit.
Therefore it pays to buy high grade fertilizers.
In buying high grade fertilizers remember that we have
in Florida a list of 14 so-called standard fertilizers. All
of these are high-grade formulas and we believe that there
is a formula on this list that will prove satisfactory for
all crops raised in this state. If you and other Florida
farmers will stick to this list of formulas when you order
fertilizers we will eventually lower the price of fertilizer.
Why? Because the fewer number of formulas the ferti-
lizer companies have to handle the smaller the expense.
If you had about 50 different lots of feed in your barn.
each of which had to be kept separate and apart from its
neighbor, and if in feeding your live stock you had to
take a little from each of the 50 lots, you know it would
take you longer than if you only had five or six different
lots. The fertilizer companies are in the same position.
only with them the longer time means more money for
time is money when you are dealing with men who get
paid by the hour..
3 I- Ju I
SOILS AND FERTILIZERS
CITRUS FERTILIZER EXPERIMENTS
By S. E. COLLISON, in Bulletin 151 of the State University
SHE judicious use of commercial fertilizers in the or-
ange grove has been one of the important problems
confronting the Florida citrus grower. In the expense
involved and the effects upon the tree and fruit, this prob-
lem ranks as of equal importance with any of the other
operations in the grove, such as spraying, harvesting,
pruning or cultivation. At the time when the work re-
ported in this bulletin was begun, practically no experi-
mental work in this line had been carried out in the state.
The existing knowledge of the effects of the various fer-
tilizers in use was entirely the result of the practical expe-
rience of the growers themselves and was of a more con-
flicting nature. In order to obtain accurate knowledge of
the effects of various fertilizers over a comparatively long
period, the experimental work discussed in this bulletin
was undertaken. A young grove was located on Lake Har-
ris, about three miles from Tavares, in Lake county, and
used for the experiment. The piece of land was selected
with special reference to protection from cold, adaptability
to citrus culture and uniformity of type of soil. It is gen-
erally considered that the influence of the fertilizer treat-
ment given citrus trees may extend over a period of several
years after that particular treatment has been discontinued.
In order to eliminate this disturbing factor from the ex-
periment it was deemed advisable to begin with young
trees. Accordingly, one-year-old budded trees, all of the
same variety, especially selected with regard to uniformi-
ty of size, and all from the same nursery, were used in
the work. They were set out in January, 1909, three-
quarters of a pound of bone meal being given each tree.
Objects of the Experiment
The objects of the experiment were to determine the ef-
fects of various fertilizers upon the chemical composition
of the soil, upon the growth and composition of the trees
and upon the fruit. The effects of lime and other alkaline
materials, and of various cultural treatments upon the soil
and upon the trees were also objects of study. To sup-
plement the work in the grove with fertilizers, a number
of soil tanks were made use of on the horticultural grounds
of the Experiment Station.
Plan of Experiment
The grove was divided into 48 plots of ten trees each.
These trees were Valencia Late on sour stock, and were
set 15 by 30 feet. The diagram in Figure 1 shows the
relation of the plots to each other. The fertilizer and
other treatment given these forty-eight plots is shown in
Table 1. A standard formula consisting of 5 per cent
3 11 [ 19 27 35 43
S I i I
41 2 20 281 136 441 1
3 11 i 2i 3 i4
7 15 23 31 39 47
2 10 18 26 34 42
s8 161 241 32\ 40 48
1 9 17 25 | 33 41 |
Fig. 1.-Diagram of plots in the ten year fertilizer experiment.
ammonia, 6 per cent phosphoric acid, and 6 per cent pot-
ash, was used. In the fall this was changed to 21/2 per
cent ammonia and 8 per cent potash, the phosphoric acid
remaining the same. The standing mixture consisted of
sulphate of ammonia, acid phosphate, and high grade sul-
phate of potash. As shown in Table 1 this mixture was
varied for different plots by substituting other sources of
s01L8s AND FERTILIZERS
the three essential elements for those in tile standard mix-
ture. The standard mixture was used at first at the rate
of 2 pounds per tree three times a year. This amount
was gradually increased so that at the end of the experi-
ment the "standard" plots were receiving an application
of six pounds instead of two.
TABLE 1.-FERTILIZER MIXTURES USED
All application ft two pounds lpr trl'e ws\\s t;ken ;as the stand-
;rd 11 amount.
SAmUllolin. 5 iper .cent.. from sulphate of
Standard formula j lhosphoric acid. i; per cent.. froinI ac;id
(for young trees) phosphate.
Potsh. ( per cenl., froin highl-grn l sill-
Sphlte of' pot'sh.
Variations from the Standard
Plot 1. Half the standard.
Plot 2. Standard.
Plot 3. I)ouble the standard.
Plot 4. Four times the standard.
Plot 5. Phosphoric acid and ammonia increased by one-half.
Plot 0. Phosphoric acid and potash increased by one-half.
Plot 7. Ammonia and potash increased by one-half.
Plot 8. Phosphoric acid and potash decreased by one-half.
Plot 9. Phosphoric acil and ammonia decreased by one-half.
Plot 10. Ammonia and potash decreased by one-half.
Plot 11. Standard and finely ground linmstoneo.
Plot 12. Standard and air-slaked lime.
Plot 13. Standard and mulch.
Plot 14. Standard.
Sources of Nitrogen
I'lot 15. From nitrale of soda.
Plot 16. Half from nitrate of soda. and half from sulphate of
Plot 17. From dried blood.
Plot 18. Half from sulphate of aminmonin, and half from dried
Plot 1If. Half from nitrate of soda. mind half from dried blood.
Plot 20. From cottonseed meal.
Plot 21. From cottonseed meal. (With ground limestone.)
Plot 22. Half from cottonseed incil and half from sulphate of
Plot 23. Half from v4ttonseed lmeal. and half from nitrate of
Sources of Phosphoric Acid
Plot 24. From dissolved boneblack.
Plot 25. From steamed bone.
Plot 20. From steamed bone. (Double amount.)
Plot 27. From Thomas' slag. (Nitrogen from nitrate of soda.)
Plot 28. From Thomas' slag. (Double amount. Nitrogen from
nitrate of soda.)
Plot 29. From acid phosphate. (Potash, 71/2 per cent. in June.
71/2 in October, and 3 in February.)
Plot 30. From acid phosphate. (Nitrogen from nitrate of soda.
Potash from hardwood ashes.)
Plot 31. From acid phosphate. (Standard.)
Plot 32. From dissolved boneblack.
Plot 33. From floats.
Plot 34. From floats. (Double amount.)
Plot 35. From floats. (Four times amount.)
Plot 30. From floats. (Four times amount. Nitror(,n from ot-
Sources of Potash
Plot 37. From low-grade sulphate.
Plot 38. From muriate.
Plot 39. From high-grade sulphale of otashl. ( With ground
Plot 40. From gainit.
Plot 41. From high-grade sulphate of potash. (Standard.)
Plot 42. From nitrate of potash. (Bala'nce of nitrogen from ni
irate of soda.)
Variations from the Standard
Plot 43. No fertilizer.
Plot 44. Standard.
Plot 45. Standard and mulch.
Plot 46. Standard and clean culture.
Plot 47. Nitrogen from dried blood. Clean culture.
Plot 48. Nitrogen from nitrate of soda. Clean culture.
FOTLO, ANI) FE'RTTLTZERS
TABLE 2.-COMPOSITION OF GROVE SOIL.
Insoluble matter ................ .......... 94.09
Volatile m atter .............. -...................j 2.55
Nitrogen .................... .................... .033
Phosphoric acid ..---------..-.....~... .. .10
Potash ................................................. .047
Soda .......................... .................. .134
Lime .............. ..... .................... .13
Magnesia ............ ........ .. .14
Manganese oxide .................... ..... ..I .10
Ferric oxide ...... ........ .......................... .98
Aluminum oxide ..---...........................- 2.30
Sulphur trioxide ....--~~~......................... trace
Carbon dioxide ........................... none
1st foot ............................ ..... .. .12
2nd foot .... .......................................... .10
3rd foot .................~. ... ................... I .09
4th foot -- .............. ................ .09
5th foot .................................................I .09
Plots 46, 47 and 48 were cultivated during the entire
year. Plots 13 and 45 were mulched with a mixture of
forest leaves, grass, etc. The remainder of the grove was
cultivated up to the rainy season (about June 1), and
then a cover crop allowed to occupy the land until in Sep-
tember, when it was either turned under or cut for hay
and the stubble plowed under. During the early years
of the experiment this cover crop consisted of beggarweed.
The soil finally became too acid to support a good crop
of the beggarweed, and was at first supplemented with
cowpeas. and later on with velvet beans.
TABLE 3.-NITROGEN AND PHOSPHORIC ACID IN SOIL
A B C D E F G Ave.
N .029 .040 .0W3 .033 .037 .030 .028 .033
P205 .09 .12 .08 .11 .12 .10 .09 .10
N .018 .018 .015 I .020 .019 .01S .016 .018
P205 .09 .12 .08 .09 .011 .08 .08 .09
The effects of the various treatments on the trees were
measured by taking at regular intervals the diameter of
the trunks six inches above the bud. Notes on the size,
general appearance and character of growth of the trees
were taken from time to time.
Composition of Soil
The soil on which the grove is located is a rather coarse
reddish sand of the hammock type, verging on high pine,
and rather dry in character. At the time that the trees
were set out composite samples of the soil (0-9 inches) and
of the sub-soil (9-21 inches) were taken and analyzed. In
one place in the field samples of the first five feet were
taken and the phosphoric acid and nitrogen contained in
the samples were determined. These analyses are given in
Table 2. Samples of the soil and subsoil were also taken
in seven different places in the field and analyzed for
phosphoric acid and nitrogen. These analyses are given
in Table 3. They show that the soil over the field was
of a fairly uniform composition. The analyses of this soil
as a whole indicate that it is somewhat above the average
in fertility as compared with citrus soils in general.
Leaching of Fertilizer
In order to supplement the work with fertilizer in the
field, soil tank experiments were begun on the Station
grounds. By this means it has been possible to more close-
ly measure and control conditions than where the work
has been conducted on the scale necessary in field experi-
ments. Accurate estimates of the losses of fertilizing ma-
terials in the drainage water under different systems of
fertilizing and the effect of long continued use of fertilizers
on the soil have been possible. In this way much interest-
ing light has been thrown upon the question of the capaci-
ty of the average sandy Florida soil for retaining the fer-
tilizing ingredients added to it and which of these ma-
terials are most subject to leaching.
The tanks were constructed of heavy galvanized iron,
painted inside and out with a chemically-resistant paint.
Each tank had an inside diameter of 5 feet 31/4 inches,
with a maximum depth of 41/2 feet, and a surface area of
one two-thousandth of an acre. As shown in the diagram,
the bottom of the tank slopes to one side, where there is a
strainer opening into a two inch tin-lined iron drainage
pipe, the length of which is a little over 4 feet. Four such
tanks open into a central collecting pit as shown in Figure
3. Under the ends of the drainage pipes entering at the
TABLE 4.-LOSS OF NITROGEN FROM SOIL TANKS
July 13 .....
Jan. 8 .
July 14 . .
Jan. 3 ...
Feb. 11 ...
Mar. 6 .
Oct. 10 .......
Oct. 23 ..
Jan. 25 .....
April 5 . .....
M ay 17 .... ... .I
2.28 72.46 3.05
11.32 61.14 15.63
20.34 40.79 33.28
22.07 37.41 54.21
13.26 24.15 35.44
2.56 21.59 10.59
3.46 55.50 16.04
11.63 43.87 20.95
7.94 73.29 18.10
.. 73.29 ....
3.46 88.52 4.72
4.23 121.65 4.78
2.38 119.28 1.95
....... 156.65 .....
2.17 173.16 1.39
.43 172.73 .25
.29 172.44 .17
.84 171.60 .48
.93 208.04 .54
4.25 241.16 2.05
1.20 239.96 .50
2.22 256.42 .92
1.52 254.90 .59
1.63 253.27 .64
.86 252.41 .34
....... 252.41 .....
four corners of the pit were placed large galvanized cans
for collecting the drainage waters. These cans were coated
on the inside with paraffine to prevent any chemical ac-
tion of the drainage water upon the metal. The collecting
pit, which is about 8 feet square inside, is built of brick,
with a concrete bottom, and is covered. The soil tanks
were sunk in the ground to within a few inches of the
tops and were filled with soil to within 3 inches of the
rims. The soil used was a rather coarse, gray sand of
high hammock type. It is described by the Bureau of
Soils as Norfolk sand. In filling the tanks a layer of
quartz pebbles was first placed over the sloping part of
the bottom in order to provide adequate drainage and to
prevent the soil from sifting through the strainer and fill-
ing the drainage pipe. Above the layer of pebbles was
placed 45 inches of soil. In excavating for the tanks the
soil was removed in layers. First a 9-inch layer was
removed and placed at one side by itself. Then the soil
was removed in one-foot layers, each foot being kept sepa-
rate from the remainder. The last foot of excavated soil
was placed in the bottom of the tank, then the remaining
sections ending with the top 9 inches. Thus the soil rested
in the tank as it was in the original state. Each layer
of soil was well packed as it was placed in the tank, the
same weight of dry soil, 8,625 pounds, being used in each.
The tanks were then exposed to natural conditions, the
drainage water leaching through the soil being collected
from time to time as it became necessary, and analyzed.
This treatment was continued for a period of 10 months
during which time the soil received no fertilizer, the re-
sults obtained representing the losses of plant food from
a bare, unfertilized soil. The results show that by far the
greatest loss of plant food falls on the nitrogen of the soil.
The thorough aeration which the soil received when the
tanks were filled would lead to more rapid nitrification
of the soil organic matter and thus to somewhat larger
losses of nitrogen in the drainage water at first, than would
occur under natural conditions. Allowing for this fac-
tor, however, the losses of nitrogen still remain very large.
During the 10 month period a loss of nitrogen equivalent
to over 800 pounds nitrate of soda per acre was noted.
The losses of potash and phosphoric acid were much small-
er, in fact, almost negligible. The loss of potash per acre
amounted to about 14 pounds, and phosphoric acid to
SOILS AND FERTILIZERSS
about a half pound. These figures show that these two
elements of plant food are locked up in the soil in rela-
tively insoluble forms which become only slowly available.
At the end of this period of 10 months, an orange tree
was placed in each tank and fertilized with a fertilizer of
the same formula as that used in the grove experiment.
The trees in all the tanks received the same amounts of
phosphoric acid and potash in the form of acid phosphate
and high grade sulphate of potash, the source of nitrogen
only being varied. The trees in tanks 1 and 2 received sul-
phate of ammonia, the tree in tank 3 nitrate of soda, the
tree in tank 4, dried blood, the same amount of actual
nitrogen being used for each tree. The same amount of
fertilizer as was used in the grove was applied to each
tree three times per year. The results of the analyses of
the drainage water collected from these tanks from time
to time are given in Table 4. These figures indicate the
extent to which the nitrogen of the three materials used
leaches through the soil. These losses are stated here in
percentages of the total amount of nitrogen applied less
the amounts lost on preceding dates. For example, the
table shows that on November 22, 1911, the drainage water
from the nitrate of soda tank contained an amount of
nitrogen equivalent to over 54 per cent of the total nitro-
gen which had been applied up to that date, less the
quantity of nitrogen already leached out up to the same
date. In other words, the percentage of loss for each date
was figured on the amount of nitrogen still remaining in
the soil at that date, and not on the total amount which
had been applied.
Loss of Nitrogen
A study of the table brings out a number of interesting
and important facts. It will be noted that while the loss
of nitrogen varies with the material used, the percentages
lost with all three materials increase from the beginning
up to November 22, and continue large until August, 1913.
For the period from July 13, 1911 to July 17, 1913, 41
per cent of the sulphate of ammonia applied to the soil
leached through and was lost in the drainage water; 72.5
per cent of the nitrate of soda, and 38.3 per cent of the
dried blood were lost. This interval of about two years
represents a period during which the trees were becoming
established and when the root system was small and
occupied but a small portion of the soil. Consequently,
much of the fertilizer was not utilized and as a result
leached through the soil and was lost. The fact that the
losses became smaller as time went on indicates that the
larger root systems were able to utilize more and more of
the fertilizer. The table also brings out important dif-
ferences in the behavior of the three different sources
of nitrogen in the soil. It will be noted that the largest
loss of nitrogen occurred with the nitrate of soda, the
losses from the other two sources being considerably less.
The larger loss of nitrate of soda is explained by the fact
that this material is very readily soluble in the soil mois-
ture and that the soil has very little if any power to retain
or fix nitrogen in the nitrate form. Consequently, if the
soil is moist and the rainfall is sufficient to more than
saturate the soil the nitrate of soda is immediately dis-
solved and much of it is carried below the range of the
plant roots. Dried blood and sulphate of ammonia differ
from nitrate of soda in their behavior in the soil.
The nitrogen in these materials is not available for
plants until it is changed to the nitrate form through the
agency of various soil bacteria in the process known as ni-
trification. In its original form the nitrogen of dried
blood is not readily soluble in the soil water, and conse-
quently very little is lost in the leaching process until
nitrification occurs. In this change the organic nitrogen
of the blood is changed first to ammonia, then to the
nitrite and finally to the nitrate form, when it becomes as
readily soluble as the nitrate of soda and is leached out
as readily. Nitrification of the dried blood is a gradual
process, extending over a period of time which may be of
several weeks' duration, depending on soil conditions. Be-
cause of this, some of the nitrogen of dried blood, or for
that matter, any similar organic material, will remain in
the soil a considerably longer time and be available to th(
crop over a longer period, than nitrate of soda. This is
especially true where heavy rains occur after the latter
has been applied to the soil.
The behavior of sulphate of ammonia in the soil is dif-
ferent from either of the two materials already discussed.
While this substance is readily soluble in the soil water
the soil has the power of fixing or absorbing at least a
portion of the ammonia, thus preventing it from leaching
away. This takes place through chemical means and is
TABLE 5.-LOSS OF POTASH BY LEACHING
Tankl 1 Tank 3 Tank 4
Sept. 5 70 107.96 .64 1.20 106.6 1.11 .80 107.16 .74
Mar. 12 543 1 3.50 173.33 1.98 3.90 168.83 2.26 2.20 175.63 1.24
April 13 .....' 2.90 224.SG6 1.67 4.10 219.16 2.43 2.00 228.06 1.14
June 10 .... 54.43 9.60 215.26 4.27 8.40 210.76 3.83 5.40 222.66 2.37
July 16 ....... 11.80 257.89 5.48 4.30 260.89 2.04 3.90 273.19 1.75
Aug. 23 ....... 10.80 247.09 .1 ........ 0.89 ........ 273.19 .......
Oct. 21 72.57 11.10 308.56 4.49 12.20 321.26 4.68 5.10 340.66 1.86
April 1 .. 54.43 2 7.10 355.89 2.30 6.80 38.89 -2.11 6.60 388.49 1.94
July 14 54.4: 6.50 349.39 1.83 (.60 362.29 1.79 6.90 381.59 1.77
Aug. 9 ... ........ 403.82 ................ 416.72 ........ ........ 436.02 ........
Oct. 31 7257 10.10 466.29 2.50 17.00 472.29 4.08 3.20 505.39 .73
Jan 3 ...... 1.00 450.29 3.43 22.50 449.79 4.76 6.70 498.60 1.32
Jan. 24 ..7.50 442.79 1.6 14.70 435.09 3.27 10.90 487.79 2.18
Feb. 11 7.00 435.79 1.58 11.20 423.89 2.57 13.60 474.19 2.79
Mar. 6 54.43 1 .30 481.92 1.90 10.20 468.12 2.41 10.20 518.42 2.15
Aug. 8 ...... 54.43 13.40 522.95 2.78 11.0 511.35 2.39 5.50 567.35 1.06
Oct. 0 .. ........ 1 .80 503.15 3.70 6.20 505.15 1.21 ........ 567.35
Oct. 23 ...... 7257 ....... 503.15 ...... 505.15 ........ 3.0 563.45 .69
Dec. 21 ... 14.00 561.12 2.90 13.40 564.32 2.65 10.30 625.72 1.83
Jan. 6 ........ 12.40 548.72 1 2.21 11.40 552.92 2.02 8.40 617.32 1.34
Jn. 25 ....... ....... 13.4() 535.32 2.44 11.80 541.12 2.13 8.10 609.22 1.31
April 5 ........j 54.43 16.50 518.82 3.08 13.90 527.223 2.57 12.00 597.22 1.97
May 17 ...... ........- 9.00 5 573.25 1.85 1 5 1.65 ..... ........ 651.65
QI:AHTERLY BULLETIN 77
common to all soils. Very sandy soils can absorb only a
small amount of ammonia; loam and clay soils are able
to absorb much larger quantities, due mainly to the clay
content of these soils. Therefore, when sulphate of am-
monia is applied to the soil at least a part of the ammonia
is absorbed by this clay present and fixed in a form which
is not readily washed out. This ammonia must be changed.
through the agency of the nitrifying bacteria of the soil.
to the nitrate form. Then it gradually becomes available
to the plant and, of course, is then subject to leaching.
These facts account for the smaller loss of nitrogen as
noted in the table, from the soil receiving sulphate of am-
monia as compared with that receiving nitrate of soda.
It should be remembered that the three sources of ammo.
nia here discussed were used side by side, in the same equiv-
alent amounts, on the same type of soil and under identical
conditions so far as these could be brought about in the
experimental work. Accordingly, the behavior of each of
these materials in the soil as compared with the others
may be taken as strictly comparative not only in this ex-
periment but under all usual conditions where they dre
used. The actual amount of each which might be lost in
the drainage on different types of soil and under varied
conditions would in all probability differ more or less
from the results given in the table. However, the fact
that nitrate of soda, for instance, leaches through to a
much larger extent than sulphate of ammonia, would hold
true under all ordinary conditions. The important facts
brought to light in the experimental work here described
regarding these nitrogenous materials and which have a
practical application in grove fertilization are as follows:
Nitrogen, the most expensive ingredient of fertilizers un-
der normal conditions and usually the element most de-
ficient in Florida soils, is the element which is lost in the
largest amounts by leaching.
The various sources of nitrogen differ greatly in their
tendency to leach out of the soil, much more of the nitro-
gen of nitrate of soda than of sulphate of ammonia being
lost in this way.
The greatest losses take place when heavy rains occur
soon after an application of nitrogenous fertilizers.
These losses decrease to a great extent as the trees be-
come older and more of the soil becomes permeated with
SOILS ANI) FERTILIZERS
Loss of Potash
Table 5 shows that a considerable loss of potash has
taken place. The figures in the potash column represent
the average losses for three soil tanks. The losses for the
first two years are small, after which they increase consid-
erably. This would indicate that during the first period
part of the potash applied was absorbed by the soil, but
that after the second year the soil had reached its maxi-
mum capacity for holding the potash and became saturated,
so to speak, so that succeeding applications were not ab-
sorbed to any extent.
It is well known that practically all soils have some
power to retain soluble potash. Sandy soils exhibit this
capacity in the least degree, while heavy clay soils will ab-
sorb large amounts. The power of a soil to fix or absorb
potash depends largely upon the presence of certain
silicates which are associated with the clay present. When
absorbed by the soil, water-soluble potash assumes a form
which is not easily leached out by water but which is still
generally regarded as being more available to plants than
the potash combinations originally present. Since Florida
soils as a general rule contain very little clay their power
to absorb potash is limited. In the work here described it
was found that at the end of four years about 30 per cent
of the potash applied had leached out, the remaining 70
per cent being used by the trees or absorbed by the soil.
In bearing groves the loss by leaching would undoubtedly
be under rather than over the 30 per cent found here.
Loss of Phosphoric Acid
No table is included to show the loss of phosphoric acid
since this loss has been extremely small. At the end of
four years it was found that only .05 of one per cent of the
amount applied was lost in the drainage water. This in-
dicates that the soil is able to absorb large amounts of
soluble phosphoric acid. That this is true is shown by
the fact that the soil used contained 50 per cent more phos-
phoric acid at the end of five years than it did at the be-
ginning of the experiment.
QUARTERLY BULLETIN 79
TABLE 6.-INCREASE IN PHOSPHORIC ACID CONTENT
Dis. bone black
Basic slag ... ...
Dis. bone black_
Floats ... .......
F loats ..........
No fertilizer ......
........ 2859 2633
...... 3601 3002
........ 4532 3449
........ 4750 3037
........ 3701 3037
....... 4080 3449
...... 3513 3002
........ 3082 2633
....... 3720 3238
..... 3916 3177
....... 3659 3356
........ 3396 2895
....... 4372 3469
. :..... 4286 3794 |
....... 3861 3554
........ 3598 2059
.... .. 3472 2839
..... 3456 2839
...... 3516 2959
..-. 4210 3554
.. 4115 3794
.. 3609 3098
... 4524 3651
..... 3643 3033
...... 3901 3236
...... 3559 3236
..---1 3434 3037
..... 4145 3651
-.. 3530 3098
... 3197 2904
.... 4091 3035
..--.-. 4466 2795
...... 3270 2795
........ 3877 3035
.. 3507 3191
-.. 3529 2904
-..-- 3432 2997
.- 3510 2820
..... 3348 3348
-..- 3815 3142
........ 3716 3348
........ 3192 2860
... 3529 2997
SOILS ANI) FERTILIZERS
In studying the effect of the fertilizer used on the com-
position of the soil, especial attention was given to the
phosphoric acid. Work at the Experiment Station with
soil tanks has shown that the loss of phosphoric acid in the
drainage water where acid phosphate was used was so
small as to be negligible, and that practically all the phos-
phoric acid applied was retained by the soil. The work
with the grove soils confirmed these results.. Samples of
soil from the fertilized plots and from the middle of the
tree rows were taken from time to time to a depth of 9
inches, and determinations made of the phosphoric acid.
Work elsewhere has shown that the greater part of the
phosphoric acid absorbed by soils is retained in the upper
plowed soil, so in this work sampling to a depth of 9 inches
was considered sufficient. The difference between the
amount of phosphoric acid in the soil of the plot and that
in the corresponding middle would show the quantity fixed
by the soil. These results for the different plots are given
in Table 6. In order to make the results easily comparable
they have been calculated to pounds per acre. The figures
in the table represent in every instance the average of the
results obtained from three different samplings of soil,
the third being taken in July, 1915. The second column
from the right shows the increase in phosphoric acid
content, due to the absorption by the soil of the phosphate
fertilizer applied. It will be noted that these figures vary
considerably among themselves, even where the amount
and form of phosphoric acid applied has been identical.
This variation can be accounted for by the difficulty of
obtaining samples of soil which are perfectly representative
of the plots. However, it will be noted that those plots re-
llte plots. However, it will be noted that those plats re-
reiving the largest applications of fertilizer also show the
greatest amounts of phosphoric acid retained. Plot 4,
receiving four times the standard quantity of fertilizer,
shows the greatest fixation, an increase of 1713 pounds
per acre being noted. The source of the phosphoric acid
on this plot was acid phosphate. Plot 36, receiving the
same amount of actual phosphoric acid as plot 4, but in
the form of floats, shows a gain practically the same as
plot 4. Both these plots show an increase of over 50 per
cent. Although five different sources of phosphoric acid
were used on the' plots, the form in which it was used does
not appear to have had any influence on the power of the
soil to absorb this material, the water-soluble form being
retained as thoroughly as the insoluble forms.
Changes of Phosphoric Acid in Soil
it is believed that the figures in the last column of Table
6 throw some light on the question as to what forms the
phosphoric acid assume after being incorporated with the
soil. It is generally agreed upon among soil investigators
that the phosphoric acid of the soil exists mainly in three
forms, namely, the phosphates of lime, iron, and alumina.
It is generally considered that the last two forms are much
less available to plants than the first form. Indeed it is
held by many that the phosphates of iron and alumina
are but slightly available because of their practical in-
solubility in the soil water. Phosphate of lime, on the
other hand, dissolves slowly in the soil water containing
carbonic acid gas and other weak acids and is thus con-
sidered more available to plants. The fixation of soluble
phosphoric acid in the soil is explained by the fact that it
combines with one or more of the compounds of iron,
aluminum or'lime present and thus assumes an insoluble
form. It then becomes a matter of some practical impor
tance to know whether the phosphoric acid added to thc-
soil assumes the form of the insoluble iron and aluminum
phosphates or the more readily available phosphate of
lime. A method of treatment which it is believed wil!
distinguish between the different forms has been developed
by soil chemists and has been used to some extent. It de-
pends upon digesting the soil in a weak solution of nitric
acid. which will dissolve the phosphate of lime present but
which has no effect upon the phosphate of iron and
alumina. A given weight of soil was treated with fifth-
normal nitric acid (about 1.26 per cent acid) and the
amount of phosphoric acid dissolved out determined, this
dissolved phosphoric acid being regarded as coming en-
tirely from the phosphate of lime present. The soil samples
used were those on which the total phosphoric acid had
been determined as shown in the table. The results given
in the table represent the difference between the amounts
dissolved from the plot soils and those of the correspond-
ing middles, thus representing the increase in the acid
soluble phosphoric acid of the fertilized plots, and are
calculated d to pounds per acre.
SOILS AND FERTILIZERS
Some interesting facts are brought out by comparing
these results with the figures representing the increase
in total phosphoric acid. Those plots showing the greatest
increase in total phosphoric acid also show the greatest
increase in acid-soluble. Plot 4 again shows the greatest
increase, followed by plot 36. The average increase in
acid-soluble phosphoric acid for all the plots (omitting
plot 43) is 494 pounds, as compared with an average in-
crease in total of 586 pounds. Assuming that the acid
used dissolved out only phosphate of lime and no iron or
aluminum phosphate, these figures indicate that about
80 percent of the increase in phosphoric acid content in
the plots has been fixed in the form of phosphate of lime.
TABLE 7.-NITROGEN CONTENT OF PLOT SOILS
Plot Nitrogen Nitrogen Plot Nitrogen Nitrogen
in Plot in Middle I in Plot in Middle
1 1140 780 25 1350 1020
2 1170 990 26 1080 930
3 1080 1050 27 1110 1080
4 810 1140 28 1140 1140
5 870 1140 29 1290 1140
6 1170 1050 30) 1020 1080
7 114( 990 31 1230 930
8 114(0 780 32 1440 1020
9 1080 840 33 1200 1050
10 990 1110 34 1140 1050
11 1170 990 35 1170 1140
12 1140 1020 36 1230 1050
13 1410 1020 37 1320 1050
14 1440 990 38 1410 1140
15 1410 1110 39 1080 1050
16 1230 840 40 1110 1050
17 1170 960 41 1230 810
18 1260 1080 42 1380 1140
19 1260 1080 43 900 990
20 1230 990 44 1230 1290
21 1320 990 45 1920 1290
22 1350 1080 46 720 990
23 1260 1080 47 780 1140
24 1440 960 | 48 720 810
Table 7 gives the amount of nitrogen in pounds per
acre to a deplh of 9 inches. The soil samples taken from
the plots and from the middles at the end of the experi-
ment in 1918. One fact brought out here is the consider-
ably smaller amount of nitrogen in the clean culture plots,
46, 47 and 48, as compared with the remaining forty-five
plots. The average amount of nitrogen in these three
plots is 740 pounds per acre, as compared with an average
for the others of 1220 pounds an acre, indicating a loss
of 480 pounds or 39 per cent. This loss must be attributed
largely to the effects of the continuous cultivation. This
practice leads to more rapid nitrification of the organic
nitrogen of the soil, changing the insoluble nitrogen to the
soluble nitrogen form which is easily leached out. This loss
of organic matter also means a decrease in the capacity of
the soil for holding moisture and soluble fertilizers added
The average of the forty-eight soils taken from the
middles is 1030 pounds of nitrogen per acre. It is interest-
ing to compare this figure with the average of fifteen sam-
plings taken at the beginning of the experiment in 1909.
These samples were taken at various places over the field
and probably give a fair average of the nitrogen content
at that time. The amount of nitrogen found in this way
was 1080 pounds per acre. This is so close to the average
for the middles (1030 pounds) at the end of the ex-
periment that it is reasonable to assume that the unfertil-
ized soil between the tree rows neither gained nor lost in
nitrogen during the ten years. In other words, the loss of
nitrogen through leaching was counterbalanced by the ad-
dition of nitrogen by means of the leguminous cover crop.
The fertilized plots have gained slightly in nitrogen as
compared with the soils from the middle of the rows.
Omilting the clean culture plots and the no fertilizer plot,
the average is 1220 pounds per acre, a gain over the
middles of 190 pounds.
Potash in Grove Soil
The amount of potash present in the different plots at
the end of the experiment in 1918 is given in Table 8.
The results are calculated in pounds per acre to a depth of
9 inches, and represent the total amount of potash in
the soil at that depth. The unfertilized middles were
also sampled, and potash determined in seven of these
soils. The average of these seven soils amounts to 1140
pounds per acre. By comparing this figure with those for
the various plots, the increase in the latter due to the
potash in the fertilizer may be determined. It will be
noted that all the fertilized plots show an increase over the
unfertilized soil, thus indicating that this soil was able to
retain at least a portion of the soluble potash applied. The
average increase for the forty-seven plots amounts to
84 SOILS AND FERTILIZERS
660 pounds per acre, or an increase of over 50 per cent for
the ten years of the experiment.
A large portion of the potash in the plot soils is held in
a very insoluble form, probably largely as feldspar. Treat-
ment of these soils with strong hydrochloric acid dissolved
on the average only 15 per cent of the total potash present.
TABLE 8.-POTASH CONTENT OF PLOT SOILS AT END OF
EXPERIMENT IN 1918
Plot P otash
1 .. .... 16 20
5 ..... 1740
14 ... 1950
23 ... .... 1440
24 ...... .. 2040
IlUfertilized soil 1140
.... ....... 1620
... .......... 1440
....... ..... 1950
.......... .. 1530
. ...... 1440
.. 1 0S
.......... .. 1830
... ........... 1620
.... ... .. | 1530
Effect of Fertilizers on Growth
The effect of the. various fertilizer treatments used in
producing growth was measured each year by taking the
diameter of the tree trunks. Table 9 gives the average
measurements of the trees in the various plots at the end
of the experiment. The measurements are given in thirty-
seconds of an inch. These figures were obtained by sub-
tracting the original diameter of the tree when set out from
the final measurement at the end of 1918. In each case
they are the average of the ten trees in each plot, and give
the actual increase made by the trees. Similar measure-
ments were taken every year during the continuation of
the experiment. The standing of the different plots from
year to year, beginning with 1910 is shown'in Table 10.
In Table 9 the plots are arranged in the order of the
increase in growth made at the end of the ten years, the
plot making the largest increase being placed at the head
of the list. This table brings out the fact that in this ex-
periment a number of sources of materials have proven
almost equally valuable in producing growth and that sev-
eral have had an injurious effect. Among the fertilizers
used on the plots making the most growth no single source
has any remarkable superiority over others used, although
there is a considerable variation in the effect of the differ-
ent materials. The results of this work emphasize the fact
that the citrus grower need not be restricted in his choice
of fertilizers to one particular material, but that there are
a number of sources of the three essential elements which
can be used to advantage. It should be stated that the soil
on which this experiment was located was somewhat above
the average in fertility, especially in phosphoric acid
content. This fact has served to minimize differences
which might otherwise have developed between the fertil-
izers used and especially the sources of phosphoric acid.
The behavior of plot 43, which received no fertilizer during
the time the experiment continued brings out the fact that
the soil was unusually well supplied with plant food.
However, a study of the table brings out the fact that the
plots making the best growth have received the standard
mixture of sulphate of ammonia, acid phosphate and high
grade sulphate of potash. Of the best 16 plots, all but one
have received acid phosphate as the source of phosphoric
acid. The one exception is plot number 25, receiving
steamed bone and ranking twelfth in the list. All but
SOILS AND FERTILIZERS
TABLE 9.-GAIN IN DIAMETER OF TREES FOR 10 YEARS
Plot Gain Fertilizer Treatment
2 T13 Standard.
1 138 One-half standard.
12 136 Standard and air-slaked lime.
13 134 Standard. Mulched.
47 133 Nitrogen from dried blood. Clean culture.
4(i 132 Standard. Clean culture.
16 130 Nitrogen, nitrate of soda, %/2 sulphate of ammonia.
45 130 Standard. Mulched.
31 128 Standard.
48 127 Nitrogen from nitrate of soda. Clean culture.
37 127 Potash from low-grade sulphate.
25 127 Phosphoric acid from steamed bone.
22 j 1260 Nitrogen, 1 cottonseed meal. % sulphate of ammonia.
S 125 j Phosphoric acid and potash decreased by one-half.
30 124 Acid phosphate, nitrate of soda, hardwood ashes.
41 124 Standard.
(; 123 lPhosphoric acid and I)otash increased by one-half.
:3; 123 Phosphoric acid from floats. (4 times amt.) Cot-
35 122 Phosphoric acid from floats. (4 times amt.)
9 321 Phosphoric acid and nitrogen decreased by one-half.
38 120 Potash from muriate.
44 118 Standard.
21 114 Nitrogen from cottonseed meal. Ground limestone.
23 114 Nitrogen, % cottonseed meal, %1 nitrate of soda.
3 114 Twice standard.
20 113 Nitrogen from cottonseed meal.
21 112 Phosphoric acid from steamed bone. (2 times amt.)
:12 112 Phosphoric acid from dissolved bone black.
34 111 Phosphoric acid from floats. (2 times amt.)
42 111 Potash from nitrate of potash. Balance nitrogen,
nitrate of soda.
1) 110 Nitrogen, 1/ nitrate of soda, 1i dried blood.
11 110 Standard and ground limestone.
24 110 Phosphoric acid from dissolved bone black.
15 100 Nitrogen from nitrate of soda.
27 109 Phosphoric acid from Thomas slag. Nitrate of soda.
7 108 Nitrogen and potash increased by one-half.
33 107 Phosphoric acid from floats.
18 106 Nitrogen, % sulphate of ammonia, 1/2 dried blood.
29 105 7/2 percent potash in June. 7%/2 in October. 3 in
40 104 Potash from kainit.
14 103 Standard.
10 102 Nitrogen and potash decreased by one-half.
43 101 No fertilizer.
28 96 Phosphoric acid from Thomas slag. (2 times amt.)
Nitrate of soda.
17 90 Nitrogen from dried blood.
39 88 Standard. Ground limestone.
5 75 Phosphoric acid and nitrogen increased by one-half.
4 65 6 Four times standard.
two plots in these sixteen have received high grade sul-
phate of potash as the source of potash. The two excep-
tions are plot number 37 receiving low grade sulphate of
potash and plot number 30 receiving hard wood ashes, and
ranking eleventh and fifteenth, respectively. Of the five
different sources of nitrogen used, all are represented in
the best 10 plots. Sulphate of ammonia, nitrate of soda,
and the nitrogen of steamed bone have all produced good
growth. It will be noted that plot number 2, receiving the
standard mixture, stands at the head of the list. As stated
elsewhere, this standard mixture consisted of sulphate of
ammonia, acid phosphate, and high grade sulphate of
potash. This mixture was applied at the rate of 2 pounds
per tree three times per, year. The amount was increased
as the trees increased in size, the application finally being
at the rate of 6 pounds three times per year.
Plot number 1, receiving one-half the standard amount,
or at the beginning 1 pound per tree three times per
year, shows practically the same increase in growth as
plot 2. Plot number 3, receiving twice the standard amount,
or 4 pounds per tree at the beginning, ranks twenty-fifth,
while plot number 4, receiving four times the standard
amount or 8 pounds per tree ranks at the foot, having made
less growth than any of the plots. The standing of this
series of four plots brings out the fact that in this experi-
ment plot 1 was receiving about the optimum amount of
fertilizer which it would pay to apply to trees of this age,
and that plot number 2 received the maximum amount
which could be applied without inducing injury. The fact
that plots 2 and 1 made practically the same amount of
growth indicates that the former was receiving more fertil-
izer than the trees could profitably use, although not enough
to injure them in any way. The appearance of these two
plots was very similar, the eye not being able to detect
any difference in size, character of growth, or appearance
of the leaves. Plot number 3, receiving twice the standard
amount of fertilizer, has developed considerable injury.
This injury was shown soon after the beginning of the
experiment, was quite severe for several years, but finally
became much less apparent. This would indicate that 4
pounds per tree three times per year was about the maxi-
mum amount of fertilizer which could be applied to young
trees and not kill them outright. The injury was severe
during the first few years but the trees managed to survive
SOILS AND FERTILIZERS
TABLE 10.-RANK OF PLOTS
Rank 1910 1911 1912 191? 1914
1 46 46 46 47 2
2 30 47 47 46 1
3 45 35 35 36 47
4 41 41 41 37 46
5 29 44 48 13 13
6 24 36 2 41 36
7 26 48 36 48 41
8 5 37 37 12 12
9 13 43 22 22 37
10 35 16 44 2 45
11 31 22 30 35 48
12 22 2 43 30 22
13 23 8 42 31 30
14 43 42 12 45 44
15 47 6 13 38 21
16 19 30 1 44 38
17 36 45 38 34 43
18 42 26 20 8 35
19 17 25 31 26 8
20 80 38 8 43 9
21 21 12 16 21 29
22 49 11 34 3 2 31
23 37 19 26 25 23
24 14 34 6 23 16
25 15 31 29 42 32
26 8 33 33 20 42
27 27 39 23 32 25
28 44 20 11 6 24
29 32 24 32 28 20
30 34 29 19 1 11
31 6 1 45 33 6
32 38 7 25 9 39
33 35 13 7 11 34
34 4 27 21 39 33
35 3 9 39 24 26
36 25 32 9 19 15
37 16 14 24 7 7
38 10 23 14 3 3
39 18 21 27 10 19
40 40 3 3 15 10
41 11 5 28 18 14
42 21 28 10 14 40
43 9 17 40 27 17
44 12 10 15 40 27
45 28 40 17 16 18
46 2 15 5 5 28
47 1 18 18 17 5
48 7 4 4 4
1 1915 1916 1917 1918
2 2" 2 2
47 1 1 1
1 46 47 12
13 13 48 13
12 12 12 47
48 47 13 46
36 48 25 16
37 45 46 45
46 25 8 31
22 37 31 48
30 22 37 37
41 36 9 25
25 30 36 22
35 31 11 8
31 41 35 30
21 8 6 41
44 35 22 6
38 11 30 36
45 9 44 35
11 (6 45 9
( 16 16 3S
43 21 20 44
9 26 24 21
29 29 23 23
23 38 32 3
8 32 29 20
16 23 26 26
32 44 21 32
34 20 38 34
26 24 42 42
24 3 3 19
15 34 19 11
20 19 15 24
42 43 10 15
28 28 14 27
10 42 34 7
3 15 27 33
33 27 33 18
39 33 43 29
19 7 18 40
27 10 7 14
7 14 40 10
14 18 41 43
40 40 28 28
18 39 17 17
5 17 39 39
17 5 5 5
4 4 4 4
and finally to overcome the injurious effects. The be-
havior of this plot in thus overcoming the injurious
effects of too much fertilizer is shown in Table 10. It will
be noted that in 1911 and 1912 this plot ranked number
forty in the list. In 1913 and 1914 it rose to thirty-
eighth; in 1915 to thirty-seventh; in 1916 and 1917 to
thirty-first; and in 1918 to twenty-fifth. This rise in
rank indicates that as the trees became older they were
better able to withstand the effects produced by too much
fertilizer. The early injury, however, resulted in a per-
manent stunting of the trees. At the end of the experi-
ment they were about three-fourths as large as the trees
of plots 1 and 2.
Plot 4 shows the maximum injury from the use of too
much fertilizer. These trees were stunted from the be-
ginning and have made very little growth. By the winter
of 1912 half of the trees in this plot were dead and had to
be replaced by others. In the spring of 1913 the excessive
applications were discontinued and from that time on
only one pound per tree was used three times per year.
The new trees used to replace those killed by the fertilizer
have failed to make much growth. At the end of the
experiment this plot was less than one-fourth the size of
plots 1 and 2 and consisted of almost worthless trees which
will probably never amount to much.
The behavior of plots number 5, 6 and 7 is interesting
in this connection, because of its bearing on the question as
to which of the fertilizing elements used was chiefly re-
sponsible for the injury produced. In this series of three
plots two of the elements were increased by one-half, the
third being used in the standard amount. In the mixture
applied to plot 6 the acid phosphate and high grade sul-
phate potash used was one and one-half times the amount
used in the standard mixture, the sulphate of ammonia
remaining the same as in the latter. Plot 7 received 1
times the nitrogen and potash of the standard and plot
5 received 11 times the nitrogen and phosphoric acid of
the standard. It will be noted that the least amount of
growth was made by plot 5 which ranks forty-seventh in
the list. This plot showed all the signs of severe injury
caused by too much fertilizer. In the table showing the
rank of the plots by years plot 5 stood forty-first in 1911
and dropped still lower from year to year. until for the last
three years it stood next to the lowest.
SOILS AND FERTILIZERS
Plot 7, where the nitrogen and potash were increased,
has made a better growth than plot 5 but not as much
as plot 6. The latter shows no injury from the increased
phosphoric acid and potash used. The trees in plot 7
show some injury caused by too much fertilizer but the
injury is not quite so marked as in plot 5. The behavior
of these three plots brings out the fact that excessive
quantities of nitrogen are much more injurious than
similar quantities of phosphoric acid and potash and that
increased ratios of nitrogen and potash are less inju-
rious than similar increases of nitrogen and phosphoric
The mulched plots and the plots which received clean
cultivation the entire year are among the best in the
grove. This treatment has been of benefit in two ways:
by conserving moisture and supplying additional nitrogen.
The cultivation through the year has led to increased
nitrification of the organic matter of the soil thus liberating
a supply of available nitrogen in addition to that supplied
in the fertilizer. Determinations on several occasions
during the early years of the experiment have shown that
these plots contained more nitrates in the soil than was
found in the soil of adjacent plots. The soil on which the
plots were located was naturally a rather dry soil so that
the continuous cultivation and the mulch of dry leaves and
weeds have aided in conserving moisture during dry
periods. Table 10 shows that the clean culture plots made
more growth than any others during the early years of the
experiment but that after 1913 they did not do quite so
well. This would indicate that for young trees continuous
clean cultivation is of benefit in promoting good vigorous
growth, but after a few years it is possible to cultivate too
much. Determinations made at the end of the experiment
show that the soil of the clean culture plots has lost about
18 per cent of the organic matter due to the continuous
cultivation as compared with the soil of adjacent plots.
PRACTICABILITY OF FERTILIZATION OF CITRUS
From "Citrus Leaves," California
SERTILIZER experiments planned and executed by
various members of the Citrus Experiment Station
staff and several individual growers on four different
citrus growing centers through five separate field trials
over a period of some fifteen years, have enabled R. S.
Vaile, of the station, to give growers eleven definite re-
commendations resulting from the work.
Location of Experiments
The five field trials were conducted at Rubidoux, near
Riverside, begun in 1907; Arlington, begun in 1915 and
closed February, 1920; Ontario, begun in 1915 and closed
in February, 1921; Chula Vista, begun in 1915 and closed
December, 1920, and at Naranjo, where the trials begun
in March, 1915. and continued until December of 1920.
Several Conclusions Reached
The basic conclusion resulting from this extended work,
is that citrus groves in Southern California must be fertil-
ized if they are to be profitable. "But little definite in-
formation was obtained concerning either the specific kinds
and amounts of fertilizer or the time and method of ap-
plication, from which the greatest returns may be ex-
pected," states Mr. R. S. Vaile in his report. "Certain
points of emphasis are consistently shown by each of these
experiments," he advises, and points out the following
1. There is a positive value to be derived from fertil-
izing citrus trees on any of the soils involved in these
trials, as measured by increased crop yield.
2. This value seems to be associated primarily with
the use of nitrogen.
3. No definite value can be attached to the use of
potash or phosphoric acid in any of the trials reported,
either when used in conjunction with nitrogen or when
SOILS AND FERTILIZERS
4. Lime, when applied as ground limestone, has not
been of value in the trials reported except at Chula Vista
on the Kimball sandy loam soil.
5. Bulky organic material has been of large importance
in citrus fertilization.
6. Specific fertilizing materials have given different
results in different locations, so much so that findings
from one set of field trials should not be too liberally in-
terpreted for any other set of conditions.
7. Trials with fruit trees are generally designed to
measure the effect of contrasting systems of orlchIrd min-
agement and can not furnish exact answers to specific
questions concerning the economy of any certain kind,
amount, or method of application of fertilizer.
8. The field trials and orchard surveys reported upon
indicate clearly that fertilization is required for the eco-
nomical production of citrus fruits under usual Southern
California conditions. That the application of fertilizer
is often delayed too long after the planting of an orchard
and that larger applications might be used with profit, are
points that are also indicated.
9. Groves that have been allowed to deteriorate through
lack of fertilizer may be greatly improved by the use of
nitrogenous fertilizer materials. Where deterioration is
manifested by typical mottle leaf and attendant character-
istics, it appears that a correction of this particular
trouble is not found in the use of commercial fertilizers,
particularly inorganic fertilizers.
10. Covering the ground with a straw mulch, thus
eliminating the necessity for any tillage operations, may
be expected greatly to improve run-down citrus groves.
This method of culture is likely to be limited in effective-
ness to a period of two or three years, following which
ordinary tillage should again be resorted to. This system
of management is not well adapted to clay loam soils.
11. The use of winter green-manure crops has been
followed by conflicting results, in different trials. In one
case a marked increase in yield and an improvement in tree
condition resulted; in a second case there was a slight
decrease in yield; in a third case the results seemed to be
negative. The failure of the cover crop to always produce
increased yields can be apparently accounted for in some
cases, but has inot been in other cases.
So far as the average grower of citrus fruits is con-
verned, the most valuable deductions resulting from this
long and tedious experimentation are the unqualified
conclusions that fertilization is required for economical
production; that the value of both potash and phosphoric
acid have been apparently greatly overestimated of late by
some growers; that nitrogenous fertilizers will greatly aid
in the rejuvenation of run-down groves; that straw
mulches, by eliminating the necessity of tillage operations
also assist in this rejuvenation and that the use of winter
green-manure crops is not yet proven to be a definite
factor in fertilization, either positively or negatively.
In April, 1907. field trials were laid out at Rubidoux to
test the effect of various fertilizers on oranges and lemons.
Twenty major plots were used, each containing 6 Wash-
ington Navel orange trees, 6 Valencia orange trees, 6
Eureka lemon trees, 6 Valencia orange trees, all budded
on sweet orange root stocks, and planted 20 feet apart
in squares. giving 108 trees per acre.
Table one shows the plot arrangement and fertilizers
used. The applications in detail were:
Plot A, nitrate of soda, blood, bone and sulfate of potash
(known as complete commercial fertilizer); plot B, no
fertilizer; plot C, dried blood; plot D, sulfate of potash;
plot E, steamed bone; plot F, stable manure; plot G, ni-
trate of soda, blood and bone; plot H, nitrate of soda;
plot I, muriate of potash (sulfate of potash 1920-1921);
plot J, superphosphate; plot K, steamed bone and sulfate
of potash; plot L, nitrate of soda, blood, and sulfate of
potash; plot M, no fertilizer; plot N, superphosphate and
blood to equal nitrogen in bone plots (blood was added in
1914); plot O, stable manure and rock phosphate; plot
P, steamed bone; plot Q, nitrate of soda, blood, super-
phosphate and sulfate of potash; plot R, sulfate of potash;
plot S, dried blood; plot T, unfertilized. Plot TT and V
contain trees on sweet orange stock, Eureka lemons,
Valencia and navel oranges, and were treated with manure
9)4 SOILS AN)D lFETILIZERS
TABLE 1.-RUBIDOUX TRIALS
Total Yield in Pounds Per Tree, Averaged for Each Plot. Nine
Seasons with Oranges, 1912-1920, Inclusive. Six Seasons
with Lemons, 1915-1920, Inclusive.*
E D C B A Plot
216 36 342 36 441 Navel
387 90 576 36 432 Valencia
169 i 52 i 400 i 75 340 Eureka
173 21 396 19 209 Lisbon
J 1 H G F Plot
72 36 252 387 378 Navel
279 153 234 414 837 Valencia
318 162 I 121 269 529 Eureka
256 196 171 230 1 726 Lisbon
0 N I I, K Plot
378 153 90 40 252 Navel
756 378 225 486 576 Valencia
503 305 i186 268 341 Eureka
800 350 180 487 36C Lisbon
V T S R Q P Plot
423 108 522 99 603 198 Navel
648 261 756 252 630 468 Valencia
630 99 500 173 530 409 Eureka
39 608 I 92 714 I 535 i Lishon
*In December, 1911. and January, 1913, the lemon yields were
seriously affected by frost, so that no data are submitted prior
to the 1914-15 season.
TABLE 2.-RUBIDOUX TRIALS
Yields by Plots in Pounds Per Tree (1). Average for Year by
1912-1914 1915-1917 1918-1920
Plot Age 5, 6, 7 Age 8, 9, 10 Age 11,12,13
Navel Val. Navel Val. Navel Val.
A 36 53 67 75 39 17
B 11 9 0 3 0 1
0 34 72 63 104 24 49
D 13 12 0 17 0 1
E 41 47 31 65 0 17
F 31 53 65 128 27 98
G 29 55 70 71 30 12
H 40 59 34 17 9 1
I 11 27 0 23 0 2
J 13 33 12 49 0 10
K 31 45 45 116 2 30
L 29 57 77 77 27 26
M 20 33 10 38 0 2
N 28 36 21 66 1 24
0 28 57 73 124 24 72
P 22 44 44 91 1 16
Q 34 52 122 130 44 24
R 24 40 9 38 0 6
S 49 56 108 135 17 62
T 27 40 9 42 0 6
U 58 95 173 146 63 138
V 36 47 75 83 30 88
(1)-Lemon yields are not included in this
frost injury during the first three-year period.
table because of
The trees were first fertilized in 1907, when small appli-
cations were made. The amounts were increased until in
1914 when the following annual applications were decided
1.34 pounds actual nitrogen per tree
2.70 pounds actual phosphoric acid per tree
1.35 pounds actual potash per tree
which means approximately 25 pounds per tree of 5-10-5
formula fertilizer on the complete fertilizer plots A and Q.
10 pounds per tree of dried blood on C and S
9 pounds per tree of nitrate of soda on H
14 pounds per tree of steamed bone on E, K, P
21/2 pounds per tree of sulfate of potash on D. I, R
13 pounds per tree of superphosphate on J
10 cubic feet per tree of manure on F and 0
8 cubic feet of manure per tree on U and V.
SOILS ANI) FERTILIZERS
Accompanying tables No. 1 and No. 2 clearly indicate
the exact yield returns in pounds and percentage of good
TABLE 3.-RUBIDOUX TRIALS
Summary of Yields by Groups of Plots.
Average Annual Yield Per Tree in Three-year Periods.
11912-1914 11915-1917 11918-1920
Group -- Treatment
NavelVal. 1NavelVal. NavelVal.
U, V ........... 27 71 124 115 46 113 Cover crop and
F. 0 ............ 20 55 69 126 26 85 Manure
S ............ 42 64 86 120 20 50 Dried blood.
S............... 40 59 34 17 9 1 Nitrate of sodai.
A, Q ............ 35 52 94 102 42 20 Complete.
G. L ........... 29 56 74 74 28 19 Two elements with
E, K, P'........ 31 45 40 91 1 21 Steamed bome.
D, I, It....... 16 26 3 26 0 3 Potash.
J .................... 13 33 12 49 0 10 Superpholsphlatt.
B, M, T........ 19 27 6 28 0 3 Unfertilized.
Eureka Lisbon Eureka Lisbon Eurieka Lislon
U, V ......................... ...... 184 .... 124
F, 0 ........................I .... .... 139 115 33 115
C, S .................. ... .... 126 99 23 68
H ........................... ... .... 40 56 0 1
A, Q ...................... .... 134 128 9 26
G, L ........................ ... .... 85 98 4 2(;
E, K, P .................. .... .... I 89 90 3 31
D, I, R .................... .... .... 40 33 3
J ............................. . .... 99 34 7
B. M, T ................. . .... 37 25 2
Other data besides yields may be of value in comparing
the effects of different treatments. The accompanying
table No. 4 gives a comparison of fruit quality for the year
1914 and for the navel crop of 1921.
Space will not permit of an exhaustive survey of the
others trials. The above tables and charts give a graphic
insight into the methods employed and the general results
obtained from the Rubidoux experiment. The general
conclusions drawn at the beginning of this article are
based on all experiments, and represent the sum total of
all deductions made. Fertilization investigation is a long,
comparatively expensive and not highly satisfactory en-
Thle net results to the grower of the years and money
expended in carrying out these experiments cannot be
measured by any existing standards. The average grower
is not in a position to carry on such extensive work and he
naturally must rely upon state and federal organizations
to protect his interests. Thousands of dollars hlave been
invested in either worthless or over-valued fertilizers dur-
ing the last few years, and the grower must have some
authentic source of information for his guidance. Many
become dissatisfied with the apparently slow progress made
by official state representatives, but it must be borne in
mind that such experiments as these in question necessarily
require many months of careful study and application,
and those responsible for the work deserve great credit.
TABLE 4.-RUBIDOUX TRIALS
Grade and Size of Fruit.
GROUPS OF PLOTS
j% Fancy& Choice % Best Sizes
S1914 1921 1914 1921
IT. V ........................ ...... ....... 60 80 48 54
1, 0 ........... ............. .............. 76 75 36 52
C. S ...................... 3...... 7.......8 40 34
H --......-..................................... 73 26 35 26
A, Q ......................................... . . ... 74 6( 44 22
G ...................... .. ............... 78 47 39 39
D I, ...... .............-................... 74 ...* 36 ...*
J ............................. ............... 72 ...* 43 .
B, M T ....................................... 71 ....* 33 ..*
*Not sufficient fruit to grade or size.
SOILS AND FERTILIZERS
THE FERTILIZING OF COTTON
Queensland Cotton Journal
NE of the boy competitors, J. Spoor, Mundubbera,
raises the above important question, and at this stage
we feel that we cannot do better than quote from the
"Georgia Experiment Station Bulletin," which gave the re-
sults of four years nitrogen test, using cottonseed meal, ni-
trate of soda, and sulphate of ammonia as sources of ni-
It will be noticed that while the yields for the four
years are low, sulphate of ammonia made the best aver-
age for three years. The tables for the fourth year show
the yield from the use of cottonseed meal and sulphate of
ammonia to be the same. I believe this can be accounted
for by the inequality of the soil. One of the cottonseed
meal plots was more fertile than any other plot.
The nitrate of soda and sulphate of ammonia for-
mulas were made to carry precisely the same number of
pounds of phosphoric acid, potash and nitrogen as was in
the cotton meal formula.
Each formula was drilled in a deep furrow and bedded
on before planting. Each plot was the same size, consist-
ing of an equal number of rows, and repeated until all
the rows were fertilized. Each year there was left as a
check, four rows in each acre not fertilized. Calculating
the cost of the nitrogen of each formula at the market
price, it is ascertained that nitrogen in cottenseed meal
costs 20 cents per pound, nitrate of soda 153/4 cents per
pound, and sulphate or ammonia 15 cents per pound. It
will be seen from this experiment running through four
years, while nitrogen from sulphate of ammonia costs
less than the nitrogen in cottonseed meal and nitrate of
soda, it made the most and the cheapest cotton.
Pounds Cottonseed Per Acre
Average for 1)09 1910 1911 1912 years.
Cottonmeal plot.... 1380 1246( 1334 1277 1309
Nitrate of Soda .... 1427 1269 1357 1257 1327
Sulfate of Ammonia 1502 1297 1416 1277 1372
Check plot not fer-
tilized ........ 889 963 940
Judging from the results I am warranted in recom-
mending sulphate of ammonia as a better source of nitro-
gen for cotton than either cottonseed meal or nitrate of
soda. I am also led to say that the cotton farmers could
save a large amount of hard earned money if they would
exchange their seed for meals and hulls and feed the meal
and hulls to cattle and apply the resulting manure to their
land, and buy sulphate of ammonia to supply the neces-
Mr. J. C. Brunnich, F.I.C., in his booklet, "Complete
Fertilizers for Farm and Orchard," supplies some valuable
formula which might be more adapted to Queensland con-
ditions than the foregoing. He says:-
Cotton does best on deep, sandy loams, or even on fairly
heavy clay, if it contains plenty of lime and a fair amount
of humus. When grown in rotation with other crops, more
particularly leguminous crops, only light dressing with
artificial fertilizers is required.
Apply per acre:-2 cwt. of supcrphosph ate or basic
superphosphate or bonemeal; 1/ cwt. of sulphate of potash:
1 to 11/ cwt. of dried blood or nitrate of soda.
Or-2 cwt. Thomas' phosphate or basic superphosphate
or rock phosphate; 1/2 cwt. sulphate of potash; 1/ cwt.
Or-3 to 4 cwt. of meatworks manure (with blood i.
1 cwt. sulphate of potash;
Or-From 3 to 6 cwt. of mixed fertilizer cottaining
8 to 10 per cent. phosphoric acid, 21/, to 3 per cent. of nitro-
gen, and 4 per cent. of potash.
In localities where the crop is susceptible to blight the
following mixture should be tried:-2 cwt. Thomas' phos-
phate or basic superphosphate or rock phosphate; 1 to b/.
cwt. Kainit; 1 to 11/2 cwt. of nitrate of soda or dried blood.
E. B. Ferris, Director of the South Mississippi Experi-
ment Station at Poplarville, Mississippi, announces that
while unfertilized plots during the past year averaged
1,239 pounds of seed cotton per acre, 500 pounds of
fertilizer per acre produced 1,800 pounds; 1,000 pounds of
fertilizer per acre produced 1,850; 1,500 pounds, 2,030,
and 2,000 pounds, 2,050 pounds of seed cotton per acre.
100 SOILS AND FERTILIZERS
Valuing the cotton at 8 cents per pound of seed cotton, and
acid phosphate at $18.00 per ton, nitrate of soda at $60.00
per ton, and potash at $50.00, the net increase from these
several applications of fertilizers by plots, beginning with
that on which 500 pounds was used, was $32.88; 1,000
pounds per acre was $28.32; 1,500 pounds per acre, $34.16;
2,000 pounds, $27.20. The fertilizer applied analyzed
In the case of similar tests with corn, using the same
fertilizer exactly, the plot on which no fertilizer was used
produced a yield of 1,238 pounds of slip-shucked ears per
acre; on the fertilized plots 500 pounds produced 3,010
pounds of corn; 1,500 pounds, 3,670; and 2,000 pounds,
3,710 pounds of corn per acre. Valuing the corn at It/
cents per pound for slip-shucked ears, which is a little
better than a dollar a bushel, the only plot showing a net
increase over the unfertilized plot was where 500 pounds of
fertilizer was used. The application of the larger anmoums
showed a loss ranging from $1.67 to $13.81.