There are many treatises available that deal with the soil, its
composition and its treatment. No attempt will be made here to go
exhaustively into that subject. There are a few fundamental factors,
however, which the potential owner should know regarding soil treatment,
for that is the base upon which he will build his income-producing
operations.
The particles of soil have had their genesis in rock. The rock has become
disintegrated and decomposed through natural processes. The action of the
weather is the most important factor in creating soil. Water falling on
rock not only wears it away mechanically, but through certain mild acid
elements which it acquires, disintegrates the binding materials that hold
rock segments together. In addition, there is the action of frost and
freezing, too, making the moisture in rock expand and contract and thereby
causing the breaking down of the segments. With this action is coupled
that of hot suns which cause expansion and breaking up of the rock as it
becomes heated and cooled under atmospheric influence.
A great deal of the soil surface in many sections of the country is the
result of glacial action. These glaciers not only eroded the surface,
thereby creating millions of rock particles, but they also carried large
deposits of the rock particles to more distant areas and deposited them
over a subsoil that may be totally different in character from the surface
soil thus deposited.
How Tillable Soil Is Made.—The action of plants themselves has a great
effect in adding to our supply of tillable soil. Seeds of plants or seeds
of trees become established in some slightly weathered rock areas and
begin to grow. The roots penetrate wherever there is any loose soil, and
partly by their pressure and partly through the acidity accompanying
decomposing plant tissue, complete a further breaking down of the rock.
There is a continuous process of destruction of rocks and leveling off of
mountains and hills to fill the valleys below.
Many groups of deep-rooted plants tend to increase the depth of the
surface soil by growth of the roots in the subsoil and by creating therein
a condition approaching that which already exists on the surface. The
action of earth worms and similar forms of life in bringing subsoil to
the top and in opening channels through which water and surface air can
penetrate constitutes another continually operating force in the creation
of a productive soil. A deeper layer of productive soil can also be
created through a plan of consistently deeper plowing, bringing up with
each annual plowing operation a small portion of subsoil which, when mixed
with the surface soil, tends to become like it.
(Courtesy New Jersey Department of Conservation and Development)
Soil is created from rock by nature’s weathering processes and by plant growth.
At the bottom may be seen solid rock; just above are disintegrating rock fragments, and at the top, the soil.
Every type of real soil contains all the elements of plant growth. This
plant food results from a breaking down of soil particles and the setting
free of chemical elements which, either singly or in combination, serve as
food for plants.
Whatever the type of soil may be, it will be found that certain crops will
make better growth in it than others. As a general rule, it may be said
that the only way to determine which plants will grow best on a given soil
is by the trial-and-error method. However, by observation of the growth on
similar types of soil we can learn something of a soil’s crop
adaptability. There are some crops that will grow in almost any soil and
there are others that need an exactness of texture, moisture and plant
food which makes them highly specialized products. The operator must learn
how to work in harmony with the peculiarities of his own soil before he
can hope to get the best results.
In acquiring a tract for the growing of plants of any kind it is desirable
to get a soil type that will meet the requirements of most plants. As a
general rule, this type contains enough clay to be retentive of moisture,
enough sand to be easily worked and is generally suitable for bacterial
growth. In other words, what is commonly called a loam is the ideal type
for general agricultural and horticultural purposes. This may be a heavy
loam, in which clay predominates, or a so-called light loam, in which sand
particles predominate. An examination of a handful of soil by a person
experienced in farming will indicate its nature and its adaptability to
ordinary crop production.
Essential Elements of Plant Food.—Countless scientific experiments in
plant growth show that potassium, lime, phosphorus, magnesium, iron,
sulphur, nitrogen, carbon, oxygen and hydrogen are essential to normal
development. The carbon, hydrogen and oxygen elements make up nearly 99
per cent of the entire composition of the plant and are derived from the
atmosphere. All of the other elements are derived from the soil except in
the case of peas, beans, clovers and other legumes which secure most of
their nitrogen from the air.
The mineral elements are not needed in large amounts but well-balanced
plant growth is strictly dependent upon their presence in available form.
Of these elements, those most likely to be deficient either in total
amount or in availability are nitrogen, phosphorus, potassium and calcium.
It is entirely feasible and economical to apply concentrated chemical
fertilizers containing the first three elements so that their lack will
not constitute a limit to size of crops harvested. In many cases it is
necessary to apply chemical fertilizers to get satisfactory yields, even
where natural manures are available and can be applied as well.
In addition to supplying essential plant food, nitrogen, phosphorus and
potassium perform specific functions in plant growth. The application of
nitrogen in one of its readily available forms (e.g., nitrate of soda and
sulphate of ammonia) will stimulate vegetative growth. If too much of this
one element is applied, leaf and branch development may occur at the
expense of the crop. Good results follow the use of nitrogen on grass sods
and on leafy vegetables like spinach. On the other hand, corn, peas, beans
and other seed-forming crops need to have the nitrogen balanced with
phosphorus. Potatoes, in common with other tuber and root crops, will
utilize plenty of potassium in the development of starch.
Sources of Plant Food.—Chemical fertilizers can be purchased at supply
stores in ready mixed condition and of analyses that will meet general
crop needs. A good formula for such a general purpose fertilizer is 4 to 5
per cent nitrogen, 7 to 9 per cent phosphoric acid and 7 to 10 per cent
potash to the ton. It is known that such a mixture will supply the food
needs of a large variety of plants in balanced amounts. Highly
concentrated mixtures are now on the market providing double the amount of
plant food in the example quoted, costing nearly twice as much but
effecting a saving by cutting in half the material handled to get the same
result. Care should be taken, in using these highly concentrated
fertilizers, to avoid contact with tender roots. A mixture for general
farm and garden purposes may contain the following ingredients:
| 100 | pounds nitrate of soda |
| 230 | pounds sulphate of ammonia |
| 250 | pounds animal tankage (7 per cent nitrogen) |
| 1,140 | pounds superphosphate (16 per cent phosphoric acid) |
| 280 | pounds muriate of potash (50 per cent potash) |
| 2,000 | pounds. |
This mixture will have a formula of 4-9-7 (4 per cent nitrogen, 9 per cent
phosphoric acid and 7 per cent potassium). The individual who wishes to
mix his own fertilizer may do so by purchasing the finely ground
ingredients separately, and by means of a shovel, integrate them all into
a mixture. Home mixing will not be found profitable where small amounts of
fertilizer are used. Those who practice home mixing for the first time
should realize that most combinations of ingredients will “set” or harden
if not used immediately, necessitating the breaking up and pulverizing of
the mass. When it is broken up after curing, no further difficulty should
be experienced with “setting” if the mixture is kept in a dry place. The
advantages of home mixing for the large user lie in lower cost per ton of
plant food as a rule; confidence in the quality of the ingredients which
he should purchase on the basis of guaranteed analysis; and the setting up
of a mixture which study of his soil and the plant requirements has
convinced him is best suited for his individual case.
Chemical Soil Analysis Not Helpful.—There is a mistaken notion that it
is necessary to analyze soils chemically in order to fertilize them
intelligently. Such an analysis of a reasonably fertile soil will show the
presence of the essential elements of plant food, though perhaps not all
in sufficient amounts, to produce ordinary crops for centuries to come.
Only a small amount of the elements become available for root absorption
each year and a chemical analysis will not bring out this most important
factor—availability. The use of a few simple tests, mainly of a physical
nature by a competent soils specialist, will prove of some assistance in
the treatment of the soil. Such tests will show the presence of adequate
amounts of humus, and indicate the acidity content. The soil texture will
give some index of its crop adaptability and thereby serve as a basis for
fertilizing treatment that will meet the needs of both soil and crop. The
practical man will not expect any considerable aid from a highly technical
and costly chemical analysis of his soil.
Another factor that militates against worth-while benefits of chemical
soil analysis is the great variation in soil types frequently occurring in
the same field. To attempt to draw a representative sample by mixing soil
from several areas might result in a specimen that would not be really
typical of any area. For the purpose of ordinary physical examination and
testing for acidity, representative soil samples should be taken from
several parts of the same soil type, mixed together and a composite sample
for testing drawn from the mixture, weighing not less than a pound in each
case. If the soil is quite apparently variable it may be necessary to draw
two or more composite samples from the same area. Very helpful service in
intelligent soil treatment may be secured from the county agricultural
agent and the state college of agriculture in the county or state of
residence.
Legumes as Soil Improvers.—A means of soil improvement that is well
understood by progressive farmers is the use of legumes to improve the
soil. The legumes include a large family of plants of which the bean, the
pea and the clovers are outstanding examples. Such plants have on their
roots nodules which house nitrogen-gathering bacteria. These bacteria
absorb nitrogen from the air in the soil and, in the ordinary process of
growth, death and decay, make this nitrogen available to the host plants,
leaving a residue in the soil for the roots of plants that are to follow.
Thus this group of plants, known as legumes, have been used for
generations as a method of increasing the nitrogen content of soils.
Nitrogen, incidentally, is the most costly element to buy in commercial
fertilizers. The soil-improving benefits of legumes may be secured by
growing them either for harvest as a source of animal food or for plowing
under as a means of utilizing them entirely for the development of soil
fertility.
In reading of the studies of soil fertility that were made by George
Washington at Mount Vernon, we learn of the improvement that he made in
the relatively poor soils of that area by growing plants of the legume
family. The actual reason why such improvement was brought about was not
known in Washington’s time, but the results were apparent. Today, the
value of legumes as soil builders is well recognized and we understand
much more definitely than Washington did the reasons for their being so
helpful in increasing crop production.
Many soil areas do not contain the particular type of bacteria necessary
to the fixation of atmospheric nitrogen by legumes. This is frequently the
cause of failure in growing alfalfa, soybeans, cowpeas and less well known
members of the legume family. Each legume has its own type of
nodule-forming bacteria. In order to assure the presence of the proper
bacterial family, means often must be employed to add them to the soil
where the specific crop is to be grown. This may be accomplished by adding
soil from an area where the legume does well to the new area, or the seed
may be inoculated with commercial cultures before seeding. Either method
is effective. If soil is used it should be drilled in or spread on a
cloudy day to prevent the destructive action of the sun’s rays on the
exposed minute forms of plant life we call bacteria.
If it is not known that the legume to be planted has been grown
successfully in a given field within the previous several years, the
precaution of adding the proper bacteria should be taken. In some
sections, such legumes as red, alsike, crimson and white clovers have been
grown for many years and the bacteria for these plants are well
distributed. There, inoculation is not necessary for these crops, but it
probably should be practiced if other legumes such as alfalfa, cowpeas or
soybeans are to be grown on land for the first time.
The Value of Humus.—In addition to the chemical elements of plant food,
all productive soils contain decaying vegetable matter, generally
classified under the term “humus.” Humus serves as a source of
acid-generating material which further breaks down soil particles and,
most important of all, serves as a food for millions of microscopic plants
which develop and die quite beyond the scope of human vision. These
constitute a type of bacteria which are distinctly beneficial and
essential to human life since they make possible the growth of larger
plants that serve as human food.
Green plants, straw or leaves, when plowed under or spaded in the soil,
are attacked by bacterial agencies which gradually turn these products
into humus. The same process occurs when a “compost” is set up. This is
made of leaves, manure, soil, straw and other materials thrown into a
heap and allowed to decay. Such compost is excellent for placing around
plants when setting them out, since it holds moisture, supplies fertility
and creates optimum conditions for young root growth. Under practical
field conditions, humus may be added to soils by spreading animal manures,
followed by plowing them down, or by the growing of heavy green crops such
as wheat, rye, cowpeas or vetch and turning the entire mass under with the
plow when they are at their height.
Lime and Its Application.—Reference has been made to the fact that
calcium is an essential plant food and is frequently deficient in soils.
As a matter of fact, the great majority of soils are deficient in calcium
and their productiveness is inhibited thereby. Lime supplies calcium and
also magnesium as food for plants. Its application accomplishes many other
desirable things such as correcting soil acidity. The growth of beneficial
bacteria is greatly stimulated in a soil that has had its acidity
neutralized by the application of lime. This product, therefore, creates a
more congenial condition for the growth of bacteria, which, in turn, make
for better crop production. Lime is also beneficial through furnishing the
element calcium with which other plant foods combine chemically and
thereby become soluble in the soil water. Unless plant foods are in a
state of solution, they cannot be absorbed by plant roots. Lime is a
potent force in creating chemical reactions in the soil, resulting in the
stimulation of growth through increased absorption of essential elements
in solution.
Lime also benefits soils of a clayey nature through its ability to cement
together the fine clay particles and in that way create air spaces so
greatly needed in tight clay soils. Lime is beneficial, too, in the case
of soils which have a large proportion of sand or large particles, and
serves as an agent in creating a better condition of tilth and of moisture
retention.
It makes little difference in what form lime is applied. It may be
purchased and applied in the form of ground limestone, a rock rich in
calcium which has been mechanically ground to a very great degree of
fineness. It can also be applied in the form of hydrated lime. This is
obtained by heating ground limestone and slaking it by adding water. A
common example of this is the slaking of lime for whitewashing purposes.
Another good source of lime is finely ground shells of oysters or other
forms of sea life which collect the calcium from sea water and deposit it
in their shells.
Adjusting the Water Content of Soils.—Aside from the supplying of water
by irrigation, a rather costly process under most conditions, the water
resources of most soils can be greatly increased by adding to their humus
content. Humus, which, it has been pointed out, is decaying vegetable
matter, serves as a sponge for the absorption of soil water and for
underground water supplies. Therefore, the more humus that can be plowed
into the soil, other conditions being equal, the greater is the ability of
the plants growing in that soil to withstand drouth. As soils are
cultivated, the tendency is for the humus to become “burned out” and to
have a reduced moisture-holding capacity. To overcome this tendency, it is
necessary to add vegetable matter to the soil whenever it is possible.
Incidentally, the incorporation of large quantities of humus in the soil
creates a condition of acidity which may call for the application of lime
as a corrective.
There are many acres of land which contain too much water in the area that
roots should penetrate to permit of optimum plant growth. Roots of most
plants will not penetrate where there is an excess of water, and air
cannot circulate where moisture is superabundant. Usually these conditions
exist where the soil is of a clayey nature. The abundance of water may be
caused by the inability of surface water to percolate through the soil. It
may take so long, due to the nature of the soil, for this water to pass
through the lower depths of subsoil that the roots of plants are destroyed
by lack of oxygen. In such cases the application of lime, increasing the
humus content, and deeper plowing will be found helpful. Occasionally, the
discharge of dynamite or blasting powder in the area, if it appears to be
in the form of a pocket, will break up the hard pan subsoil and permit the
water to escape. Less dependence is now being placed on this means of
correcting a wet condition of the soil than was the case some years ago.
A similar condition of overabundant water in soil may be due to the
presence of springs or to a high water table. Little can be done to
correct a condition where the water table itself is so close to the
surface as to inhibit plant growth and this is assuredly one of the
factors to be looked into before a tract is purchased. Where the surplus
water is evidently being supplied by a spring, an underdrain made of tile
pipe, 3 or 4 inches in diameter, can be laid as a means of conducting the
water into a ditch or adjoining drain. In laying such a drain, it should
be placed above the area where the wet soil surface is most evident. If
such a drain is laid 18 inches to 3 feet deep above the wet area, it will
cut off the water seeping down underground and carry it away. Good results
cannot be secured if the drain is laid directly in the area of extreme
wetness or if it does not cut off the flow of water before it reaches the
area that is consistently too wet for plant growth.
From what has been said in this brief description of soil treatment and
soil improvement, it is evident that one must live with his soil for some
time in order to understand it and to be able intelligently to correct its
deficiencies, overcome its weaknesses and make it capable of supporting
plants which are desirable from the owner’s point of view. In the great
majority of cases, the improvement process, while a slow one, is far from
hopeless and almost any soil that is not extremely sandy or clayey can be
so intelligently treated as to make it productive.
Cultivation.—Any discussion of soil treatment is not complete without
mention of cultivation. Intelligent cultivation is an essential factor in
securing adequate crops. It is interesting to recall that the word
“manure,” which has come to mean fertilization or fertilizer, is derived
from the Latin word “manus” meaning “hand” and implying “manipulation”
of the soil, which we now call cultivation. Cultivation has been most
frequently practiced as a method of destroying weeds, thereby making all
of the available plant food subject to absorption by the roots of the
desired plants and not by the intruders we call weeds. Cultivation does
more than destroy weeds, however. It opens up the soil so that air
containing atmospheric nitrogen can penetrate it and so that the bacteria
requiring air for their best growth may have it available. Furthermore,
cultivation conserves moisture and is more essential during dry periods in
the growing season than at any other time.
We know that in entering the soil the rain water follows certain channels
in and around the soil particles on its way to the subsoil. When the rain
has ceased and the top layer of soil becomes dry, the tendency is for the
water to work up through these same channels to the surface, where it
evaporates. Cultivation, by breaking up these channels, or capillary
tubes, checks the escape of moisture into the air. It creates a blanket of
dry surface soil which insulates the soil moisture from the air above. The
tendency of soil moisture to reestablish capillary methods of escape makes
recultivation necessary from time to time in dry weather. Care must, of
course, be taken that the cultivation is not harmful to roots of growing
plants. If these roots are disturbed or destroyed through cultivation,
more harm than good may result because of the damage to the root systems.
Farm Power and Equipment.—Where the land area to be cultivated is
larger than the family garden some type of equipment for working the land,
propelled by horse or motor, will be found desirable and in larger areas
essential. One or more horses may be used where there are stabling
facilities and where arrangements can be made for the daily care and
feeding that these animals require. A horse suitable for work purposes may
be obtained for less than $200. The price will, of course, depend upon the
age and physical soundness of the animal, but should not exceed $150 for a
physically sound animal under ten years old. A person unskilled in the
assessing of animal values should obtain the services of a veterinarian or
an experienced horseman in making a selection. A horse for this purpose
should be of quiet, tractable disposition, bred and broken for work
purposes. The cost of caring for a horse for one year will approximate
$125, including feed and bedding, but without labor charge.
Leather harness costing $25 to $50 will be required and in addition tools,
including a plow, a harrow, and a cultivator costing about $15 each. Other
special equipment such as a mower will cost considerably more, depending
upon the type used.
If the members of the family are fond of animals and willing to assume the
responsibility for their daily care, the horse will be found an efficient
and useful source of power for tilling the land. In this connection it
should be pointed out that flies breed with great rapidity in the strawy
manure of the stable, and such wastes should be spread upon the land
almost daily or treated to prevent fly-breeding.
Tractor Power.—Just as large tractors have supplanted horses and
horse-drawn equipment on thousands of farms in the United States, the
so-called garden tractor has become increasingly popular for the tilling
of small acreages. The tractor requires “feed” only when it is working, is
not subject to the ills that beset animals, and may be used for
twenty-four hours a day if necessary. It makes an appeal to the
mechanically minded members of the household and, if properly cared for,
will give economical and lasting service.
The usual type of garden tractor consists of two large wheels with lugs on
them to give traction and is driven by a one- or two-cylinder motor. A
plow, a cultivator, or mower may be attached to the drawbar, the operator
walking behind and regulating the speed and guiding the outfit by handles
provided for the purpose. Earlier types of these machines were not always
satisfactory owing to construction weaknesses and occasionally balky
motors. Those now on the market, however, are greatly improved, require
less attention, and rival their big brothers, the powerful farm tractors,
in dependability.
There are a number of types and makes of garden tractors now on the
market, ranging in price from $175 or less to $400, the cost depending
largely upon the size and capacity of the motor. In selecting a
satisfactory garden tractor attention should be directed to the simplicity
and power of the motor, the type of bearings, the method of lubrication of
all moving parts, the working speed and the economy of fuel. Bearings
ought to be of standard, long-wearing type since these are subject to hard
service. Two speeds are desirable, a slow one for heavy duty and a faster
one for lighter work. The tractor should operate all day on about 2
gallons of gasoline and a quart of oil. In addition to power applied at
the drawbar where special tools are attached, a pulley will be found a
desirable accessory for operating belt machinery such as small feed mills,
pumps, and cream separators. The rating of the motor should be not less
than 3 horsepower at the drawbar for the ordinary tasks it will be called
upon to perform.
All types of attachments are available for the garden tractor. These
include plows, disks, harrows, cultivators, mowers, fertilizer
distributors, planters, sowers and seeding accessories. The prices of
these vary according to make and quality. Levers are provided for
adjusting the depth of plowing, cultivating and seeding. Some of the large
type garden tractors are equipped with a seat on a sulky attached to the
machine so that the operator can ride and have complete control over speed
and the type of work he wishes to do. A modern garden tractor will be
found very useful in taking care of a lawn or garden. In the case of
larger areas under cultivation, but not of field size, this type of
machine is rapidly gaining popularity for performing efficiently and
economically the numerous jobs that are to be done on every small farm.
Do’s
Select a soil type that is inherently productive, fertile, retentive of moisture and easily cultivated.
Supplement soil fertility by adding chemical fertilizers either singly or in combination.
Buy mixed fertilizers on the basis of guaranteed analyses.
Use legumes (peas, beans, etc.) to add nitrogen to soils and increase humus content.
Add specific bacteria for the production of various legumes.
Use manure and green crops to supply humus.
Apply lime when soil test shows need for it as plant food and general soil improver.
Practice methods that make soils absorptive of moisture and permit escape of excess water.
Cultivate the soil to check escape of moisture and to kill weeds.
Use a horse or garden tractor for cultivation of areas larger than the family garden.
Don’ts
Don’t buy land that is continually wet and swampy.
Don’t expect to produce satisfactory crops on soils that are extremely
heavy or clayey or so sandy as to quickly lose moisture and fertility.
Don’t try to produce crops without maintaining the humus supply in the soil.
Don’t neglect cultivation as a means of conserving moisture, destroying weeds and stimulating root growth.