nference is fairly safe that a test would show that the soil
is sour.

_When Production Decreases._ It is not a matter of any moment to the
owner of a productive soil whether or not his soil would give an acid or
an alkaline reaction under test. Returns from his labor are
satisfactory. Some land in this class is not strictly alkaline. The man
most interested in the effects of lime applications is the one who is
not satisfied with yields. The tests for acidity have been so many
throughout our eastern and central states that the owner of land which
is not productive has reason for the presumption that its percentage of
lime is too low. There is danger of error, and a scientific test is
surer, but in most cases the land which has been reduced from a fertile
to an unproductive state has lost its alkaline nature.

_Naturally Thin Soils._ Nature may be prodigal in supplies of nearly all
the elements of plant food to land and yet skimp its supply of lime,
but naturally poor soils are quite surely in the acid class. The
exceptions in our humid region are not extensive. When improvement is
planned for, involving additions of organic matter and plant food, the
application of lime to correct acidity is the first requirement. If such
land could be given the characteristics of a limestone soil so far only
as the lime factor is concerned, the building up of fertility would be
relatively easy. Liming must form the foundation of a new order of
things. The ability to grow the clovers and to furnish rich vegetable
matter to the soil, which naturally is poor in humus, rests upon lime
application first, and then upon any supply of plant food that may
continue to be lacking.

CHAPTER V

TESTS FOR ACIDITY

_The Litmus Paper Test._ A method of testing soils for acidity, which
has been in use for many years, is the simple litmus paper method.
Because of its simplicity and fair degree of accuracy, the litmus paper
test is still used to a considerable extent in estimating the degree of
acidity of certain soils. The best manner of using litmus is to place a
strip of the blue paper in the bottom of a glass saucer, covering it
with filter paper or other paper which is neutral--that is, paper which
is neither acid nor alkaline.

A small quantity of the soil to be tested is moistened with rain or
distilled water and placed on this paper. If the acid is present the
blue paper will be changed to a reddish color, varying in intensity
acc