Manuring The Soil
In the early days of our history, when the soil was new and rich, we
were not compelled to use large amounts of manures and fertilizers. Yet
our histories speak of an Indian named Squanto who came into one of the
New England colonies and showed the first settlers how, by putting a
fish in each hill of corn, they could obtain larger yields.
If people in those days, with new and fertile soils, could use manures
profitably, how much more ought we to use them in our time, when soils
have lost their virgin fertility, and when the plant food in the soil
has been exhausted by years and years of cropping!
To sell year after year all the produce grown on land is a sure way to
ruin it. If, for example, the richest land is planted every year in
corn, and no stable or farmyard manure or other fertilizer returned to
the soil, the land so treated will of course soon become too poor to
grow any crop. If, on the other hand, clover or alfalfa or corn or
cotton-seed meal is fed to stock, and the manure from the stock returned
to the soil, the land will be kept rich. Hence those farmers who do not
sell such raw products as cotton, corn, wheat, oats, and clover, but who
market articles made from these raw products, find it easier to keep
their land fertile. For illustration: if instead of selling hay, farmers
feed it to sheep and sell meat and wool; if instead of selling cotton
seed, they feed its meal to cows, and sell milk and butter; if instead
of selling stover, they feed it to beef cattle, they get a good price
for products and in addition have all the manure needed to keep their
land productive and increase its value each year.
1, clay subsoil; 2, same, with fertilizer; 3, same, with humus]
If we wish to keep up the fertility of our lands we should not allow
anything to be lost from our farms. All the manures, straw, roots,
stubble, healthy vines--in fact everything decomposable--should be
plowed under or used as a top-dressing. Especial care should be taken in
storing manure. It should be watchfully protected from sun and rain. If
a farmer has no shed under which to keep his manure, he should scatter
it on his fields as fast as it is made.
In left top pot, no plant food; in left bottom pot, plant food scanty;
in both right pots, all elements of plant food present]
He should understand also that liquid manure is of more value than
solid, because that important plant food, nitrogen, is found almost
wholly in the liquid portion. Some of the phosphoric acid and
considerable amounts of the potash are also found in the liquid manure.
Hence economy requires that none of this escape either by leakage or by
fermentation. Sometimes one can detect the smell of ammonia in the
stable. This ammonia is formed by the decomposition of the liquid
manure, and its loss should be checked by sprinkling some floats, acid
phosphate, or muck over the stable floor.
Many farmers find it desirable to buy fertilizers to use with the manure
made on the farm. In this case it is helpful to understand the
composition, source, and availability of the various substances
composing commercial fertilizers. The three most valuable things in
commercial fertilizers are nitrogen, potash, and phosphoric acid.
The nitrogen is obtained from (1) nitrate of soda mined in Chile, (2)
ammonium sulphate, a by-product of the gas works, (3) dried blood and
other by-products of the slaughter-houses, and (4) cotton-seed meal.
Nitrate of soda is soluble in water and may therefore be washed away
before being used by plants. For this reason it should be applied in
small quantities and at intervals of a few weeks.
Potash is obtained in Germany, where it is found in several forms. It is
put on the market as muriate of potash, sulphate of potash, kainite,
which contains salt as an impurity, and in other impure forms. Potash is
found also in _unleached_ wood ashes.
Phosphoric acid is found in various rocks of Tennessee, Florida, and
South Carolina, and also to a large extent in bones. The rocks or bones
are usually treated with sulphuric acid. This treatment changes the
phosphoric acid into a form ready for plant use.
These three kinds of plant food are ordinarily all that we need to
supply. In some cases, however, lime has to be added. Besides being a
plant food itself, lime helps most soils by improving the structure of
the grains; by sweetening the soil, thereby aiding the little living
germs called _bacteria_; by hastening the decay of organic matter; and
by setting free the potash that is locked up in the soil.
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