Checking the Waste | Page 6

produced
to supply the demand.
So we can see that it is absolutely necessary that the soil be properly
cared for if we are to continue to increase and prosper, for as Secretary
Wilson has said, "Upon the fertility of the soil depends the whole
business of agriculture."
The soil is exhausted in two ways: (1) By erosion, or the carrying away
of the entire soil itself. (2) By so using the soil that one or more of its
principal elements are worn out. We shall consider this form of soil
exhaustion first, because it more directly concerns the work of every
farmer.
By a fertile soil is meant one that has an abundance of plant food in the
proper proportions. The soil contains all the elements that are needed to
support life, but they are in an inorganic form, that is, they are lifeless.
Plants alone can take these inorganic substances from the soil, and
change them into starch, sugar, fats, and protein. All animals, including
man, must get these substances through plants, or through other
animals that have already absorbed them from plants.
The soil contains ten elements that are absorbed or assimilated by
plants. These are: (1) lime, (2) magnesia, (3) iron, (4) sulphur, all of

which are found in most plants in very small proportions, and are
present in most soils in quantities far beyond the needs of crops for
ages to come; (5) carbon, which is obtained by plants through their
leaves directly from the air and the sunshine; (6) hydrogen and (7)
oxygen, which are taken from the water in the soil and carried to the
leaves, where they also help to take the carbon from the atmosphere.
With none of these elements, then, does the farmer need to concern
himself in regions where the water supply is abundant, as they are, and
will continue to be, plentifully supplied by nature. But the other three,
(8) nitrogen, (9) potassium, and (10) phosphorus, are needed by plants
in large quantities, and are taken from the soil far more rapidly than
nature can replace them.
All these elements are necessary to plant life, but some plants require a
large amount of one element, others a small proportion of that, but a
large amount of some of the others. No two varieties of plants require
exactly the same proportions, so it is easy to see that the plant that takes
out of the soil any one element makes the soil less capable each year of
producing a good crop of the same kind.
In the early days of farming in this country, it was the custom to grow a
single crop, which had been found to give good results, year after year
in the same field. In Virginia and other near-by states nearly all the best
land was given every year to the cultivation of tobacco, which exhausts
the soil rapidly. In the states farther north other crops were planted in
the same way. As a result, some of the most fertile soil in Virginia, the
Carolinas, Massachusetts, and other eastern states has been so
exhausted that it is no longer worth cultivating. Everywhere throughout
the New England states are to be found these worn-out farms, and,
while they were never so fertile as the lands of the Mississippi Valley,
each one was rich enough to support a family in comfort, with
something left to sell; but because they were required to produce the
same crops, and so take the same element from the soil, year after year,
they have become so lacking in one of the essential elements that they
are unfit for cultivation, and have been abandoned.
It is wisdom and good business policy for farmers to study carefully

this question of plant food and to learn what each crop is taking from
the soil, so that it may be replaced. It has been found by long and
careful experiments, that when land has been "single cropped," as this
abuse of the land is called, for a long time, the soil has been almost
entirely deprived of its nitrogen. As you know, nitrogen is one of the
elements of the air, so that there is a never-ending supply, but most
plants are unable to take it from the air, and until the last few years the
task of replacing nitrogen in the soil was considered impossible. Recent
discoveries, however, have shown that there are two ways in which it
may be done. By means of electricity, nitrogen may be directly
combined with the other elements of the soil. The other method is
nature's own plan, and so is easier and cheaper. It has been found that
while most plants exhaust the nitrogen from the soil, one class of plants,
the legumes, of which beans, peas, clover, and