Amount Of Lime Per Acre
from Right Use Of Lime In Soil Improvement
Soils Vary in Requirement. There is always the insistent question
respecting the amount of lime that should be used on a particular field.
Usually no definite reply can be safely made. The requirement of the
present, and probably of the next few years, should be met by one
application. The existing degree of acidity is an unknown quantity until
a careful test has been made. There are soils so sour that several tons
of fresh burned lime per acre would only meet present requirement, and
there are soils so soundly alkaline that they need none at all. This
uncertainty regarding amount required is responsible for much failure to
do anything, even when some acidity is indicated by general appearance.
A Working Basis. If land has once been productive and in later years
clover has ceased to grow and grass sods are thin, there is a strong
probability that liming will pay, and the experience of farmers on
normal soils, and the tests of experiment stations, justify the
estimate that two tons of fine stone, or one and a quarter tons of fresh
burned lime per acre, can be used with profit. This amount probably will
permit fertilizers and tillage to make their full return in heavy sods
that will provide humus. It is a reasonable expectation that the
application will serve through a crop rotation of four or five years.
If the soil was not very sour, the second application at the end of four
or five years may be reduced somewhat, and even a ton of stone given
once in the crop rotation may fully meet the requirement.
In the case of the normal soil that has ceased to grow clover, and does
grow plants that are acid-resistant, it is better practice to secure a
relatively low-priced supply of coarsely pulverized stone and apply
three or four tons per acre, and thus lengthen the interval between
applications to eight or 10 years. The fine material in the heavy
application will take care of present need, and the coarser particles
will disintegrate later on.
The quantities suggested may not be the most economical for the reader,
but their use cannot be attended by loss if a soil is sour, and there
is reason to believe that it is much better to use such quantities
without question than to defer liming for a year in the hope that some
more definite knowledge of a particular field's needs may be secured.
Small Amounts Per Acre. There is much experience as a basis for the
claim that a few hundred pounds of burned lime per acre may have marked
results. Fields that indicated an actual lime requirement of a ton of
fresh lime per acre have had a test of 500 pounds per acre made in
strips, and the clover later on was so superior to that which was
struggling to live in the untreated portion that the light application
appeared almost to be adequate. In such land there cannot be full
bacterial activity or continuing friendliness to plants unless the need
is met fully. A larger application would have paid better. It is the
soil rich in lime that can make the best response to tillage and
fertilization.
A Heavy Soil. When burned lime is not high in price, an application of
two tons per acre may be more profitable than a smaller one. A heavy
soil needs to be richer in lime than a light one for best results, and
physical condition also is improved by the larger quantity. A
correspondingly heavy coat of stone will give quite satisfactory
results, but effect upon the texture of the soil is less marked.
Sandy Soils. It is inadvisable to apply any large quantity of caustic
lime to a light soil. Such a soil does not need as high a percentage in
it as a heavy soil requires for good results, and caustic lime can
easily injure physical condition. Limestone is safe for use, and is to
be advised for all quite sandy land. Acidity rarely runs high in a light
soil, and the opinion is hazarded here that one ton of stone per acre
meets the needs of a light soil about as surely as two tons supply a
heavy soil. In case of each type of soil there are wide exceptions, and
yet these estimates form a basis for the judgment of the individual
farmer.
Next: Special Crop Demands
Previous: Methods Of Application
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