h 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