AMOUNT OF LIME PER ACRE
_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.
CHAPTER VIII
SPECIAL CROP DEMANDS
_Lime-Loving Crops._ There are plants which are acid-resistant, giving a
good return for fertilization and care when the soil is sour. There are
a few kinds of cultivated plants that seem to prefer an acid soil, and
to resent lime applications. Most staple crops prefer an alkaline soil,
or at least one that has no large requirement, and there are plants that
thrive best only in land rich in lime. Not all such plants require more
as a component part of their structure, but do have a high percentage in
their ash.
_Liming for Alfalfa._ When all other conditions are right, alfalfa
thrives or fails according as a soil is rich in lime or is distinctly
deficient. It is entirely possible to get fair yields of this legume for
a short time from land that is not fully alkaline, but full yields and
ability to last for a term of years depend upon a liberal lime supply.
Alfalfa is at home only in a naturally calcareous soil, or one that has
been given some of the characteristics of such land by free use of
lime. In the case of neutral or slightly acid ground it is good practice
to mix four tons of limestone per acre thoroughly with the soil. Such
treatment gives greater permanence to the seeding, enabling the plants
to compete successfully with the wild grasses and other weeds that are
the chief obstacle to success in the humid climate of our Mississippi
valley and eastern states. When this amount of stone is used, the finest
grade may not be preferred to material having a considerable percentage
of slightly coarser grains.
[Illustration: Remarkable Effect of Lime on Sweet Clover at the Ohio
Experiment Station]
[Illustration: Sweet Clover Thrives When Lime and Manure Are Supplied,
Ohio Experiment Station]
_Red Clover._ When land is in excellent tilth, it may grow red clover
satisfactorily while showing a decided lime deficiency. On the other
hand, much slightly acid land fails to grow clover, and an application
of lime is followed by heavy growths. Red clover is most at home in
calcareous soils, and lack of lime is a leading cause of clover failure
in this country. Other causes may be important ones in the absence of
lime and be overcome when it is present.
_Alsike Clover._ Most legumes like lime, and alsike clover is not an
exception, but is far more acid-resistant than the red. It is less
valuable, both for soil improvement and for forage, having an inferior
root system, but has proved a boon to farmers in areas that have been
losing the power to grow red clover. The custom of mixing red and alsike
seed has become widespread, and distinctly acid soils are marked in the
clover flowering season by the profusion of the distinctive alsike bloom
to the exclusion of the red. While there is acid-resistant power, this
clover responds to liming.
_Crimson Clover._ Among lime-loving plants crimson clover has a rightful
place, but it makes fairly good growth where the lack of lime is marked.
_Bluegrass._ The heaviest bluegrass sods are found where lime is
abundant in the soil. This most valuable pasture grass may withstand the
encroachments of weeds for a long time when lime is not abundant, if
plant food is not in scant supply, but dependable sods of this grass are
made only in an alkaline soil. Heavy liming of an acid soil pays when a
seeding to permanent pasture is made, and old sods on land unfit for
tillage may be given a new life by a dressing.
_Crops Favored by Lime._ Nearly all staple farm crops respond to
applications given acid soils. Corn, oats, timothy, potatoes and many
other crops have considerable power of resistance to acids, but give
increased yields when lime is present. Liming is not recommended for
potatoes because it furnishes conditions favorable to a disease which
attacks this crop. When clover is wanted in a crop rotation with
potatoes, it is advisable to apply the lime immediately after the potato
crop has been grown, and to use limestone rather than burned lime. Most
kinds of vegetables thrive best in an alkaline soil.
INDEX
Page
Air-slaked lime, composition and relative value of, 31, 57
Agricultural lime, composition and relative value of, 58, 76
Amount of lime per acre, 82
Basic slag, 76
Burning lime, methods of, 49
Calcium, 29
carbonate, 30
hydroxide, 30
oxide, 29
Carbon dioxide, 30
Causes of soil acidity, 10, 12, 13, 14
Caustic lime affects physical condition, 44, 46
acts on humus, 44, 47
frees inert plant food, 44
compared with limestone, 45
irrational use of, 44
may injure a sandy soil, 66, 85
right use of, 48
Caustic magnesian lime on sandy land, 66
Chemical changes produce acidity, 13
Clover, 17, 19, 87
Composition of limestone, 24, 30, 31, 46
Distribution of lime, 70, 78
Distributors, 80, 81
Dolomite, 30, 67
Equivalents in value, 69
Extent of soil acidity, 6, 11
Fineness of limestone, 39, 73
Frear, Dr. Wm., 50
Fresh burned lime, 44
composition and relative value of, 29, 31, 45, 69, 71
Gas lime, 62
Ground limestone, composition and relative value of, 30, 33, 69, 72
Hydrated lime, composition and relative value of 30, 31, 53, 71
Indications of soil acidity, 5, 15, 17, 18
Irrational use of lime, 9, 44
Land plaster, 76
Leaching, 12, 38
Lime for alfalfa, 86
alsike clover, 87
bluegrass, 88
crimson clover, 88
potatoes, 89
red clover, 87
most staple crops, 88
in fertilizers, 77
is unstable, 10
necessary content variable, 5
on sandy soils, 85
Limestone burned to effect distribution, 34
land, value of, 4, 6
varies in composition, 33
Litmus paper test, 20
Low-priced pulverizers, 35
Lump lime and hydrate compared, 71
limestone compared, 72
Magnesian lime, 64
limestone, 66
Magnesium, 30, 64
Marl, composition and relative value of, 59, 76
New York experiment station, 42
Old heaps of burned lime, 58
Oyster shells, composition and relative value of, 61, 75
Redtop, 18
Relative values of lime, 68, 71, 72
Removal of lime in crops, 14
Slaking lime, 53
Small applications may pay, 84
Soil acidity, cause of, 10, 12, 13, 14
extent of, 6, 11
indications of, 5, 15, 17, 18
tests for, 20, 21
Soils vary in lime requirement, 82
Sorrel and plantain, 15
Spreading farm-burned lime, 70, 80
Storing lime in the soil, 38
Storing limestone, 73
Source of lime, as:
agricultural lime, 58, 76
air-slaked lime, 31, 57
fresh-burned lime, 29, 31, 44
gas lime, 62
ground lime, 31
ground limestone, 30, 33
hydrated or slaked lime, 31, 53
magnesian limestone, 30
marl, 59
oyster shells, 61, 75
wood ashes, 61, 75
Source of lime in soils, 10, 24
Technical terms, 28
Tests for soil acidity, 20, 21
Thin soils usually acid, 18
Timber as an index, 7, 15
Timothy, 17, 88
Truog, Prof. E., 21
Truog test, 21
Value of lime after magnesium removal, 62
Voorhees, Dr. E. B., 62
Warding off soil acidity, 7
When production decreases, 18
Wood ashes, composition and relative value of, 25, 61, 75
End of Project Gutenberg's Right Use of Lime in Soil Improvement, by Alva Agee