is the cheapest and surest way of
overcoming the sourness. In addition to sweetening the soil by
overcoming the acids, lime aids the land in other ways: it quickens the
growth of helpful bacteria; it loosens stiff, heavy clay soils and
thereby fits them for easier tillage; it indirectly sets free the potash
and phosphoric acid so much needed by plants; and it increases the
capillarity of soils.

However, too much must not be expected of lime. Often a farmer's yield
is so increased after he has scattered lime over his fields that he
thinks that lime alone will keep his land fertile. This belief explains
the saying, "Lime enriches the father but beggars the son." The
continued use of lime without other fertilization will indeed leave poor
land for the son. Lime is just as necessary to plant growth as the
potash and nitrogen and phosphoric acid about which we hear so much, but
it cannot take the place of these plant foods. Its duty is to aid, not
to displace them.

We can tell by the taste when salads are too sour; it is more difficult
to find out whether land is sour. There are, however, some methods that
will help to determine the sourness of the soil.

In the first place, if land is unusually sour, you can determine this
fact by a simple test. Buy a pennyworth of blue litmus paper from a drug
store. Mix some of the suspected soil with a little water and bury the
litmus paper in the mixture. If the paper turns red the soil is sour.

In the second place, the leguminous crops are fond of lime. Clover and
vetch remove so much lime from the soil that they are often called lime
plants. If clover and vetch refuse to grow on land on which they
formerly flourished, it is generally, though not always, a sign that the
land needs lime.

In the third place, when water grasses and certain weeds spring up on
land, that land is usually acid, and lime will be helpful. Moreover,
fields adjoining land on which cranberries, raspberries, blackberries,
or gallberries are growing wild, may always be suspected of more or less
sourness.

Four forms of lime are used on land. These, each called by different
names, are as follows:

First, quicklime, which is also called burnt lime, caustic lime,
builders' lime, rock lime, and unslaked lime.

Second, air-slaked lime, which is also known as carbonate of lime,
agricultural lime, marl, and limestone.

Third, water-slaked, or hydrated, lime.

Fourth, land plaster, or gypsum. This form of l