Fertility Value
Categories:
THE CLOVERS
Attempts have been made to express the actual value
of a good clover crop to the soil in terms of money. The number of
pounds of matter in the roots and stubble has been determined, and
analyses show the percentage of nitrogen, phosphoric acid, and potash
contained. The two crops harvested in the second year of its growth
likewise have their content of plant-food determined. If the total
amounts of nitrogen, phosphoric
acid, and potash have their values
fixed by multiplying the number of pounds of each ingredient of
plant-food by their respective market values, as is the practice in the
case of commercial fertilizers, a total valuation may be placed upon
the clover, roots and top, as a fertilizer. Such valuation is so
misleading that it affords no true guidance to the farmer. In the first
place, the phosphoric acid and potash were taken out of the soil, and
while some part of these materials may have been without immediate
value to another crop until used by the clover, no one knows how much
value was given to them by the action of the clover. Again, no one
knows what percentage of the nitrogen in the clover came from the air,
and how much was drawn from the soil's stores. The proportion varies
with the fertility of the land, the percentage of nitrogen taken from
the air being greater in the case of badly depleted soils.
A big factor of error is found in the valuations of the ingredients
found in the crop. All plant-food is worth to the farmer only what he
can get out of it. He may be able to use 50 pounds of nitrogen per acre
in the form of nitrate of soda, at 18 cents a pound, when growing a
certain crop, but could not afford to buy, at market price of organic
nitrogen, all the nitrogen found in the clover crop, and therefore it
does not have that value to him.
On the other hand, these estimates do not embrace the great benefit to
the physical condition of the soil that results from the incorporation
of a large amount of vegetable matter.
Discussion has been given to this phase of the question in the interest
of accuracy. Values are only relative. The practical farmer can
determine the estimate he should put upon clover only by noting its
effect upon yields in the crop-rotation upon his own farm. It is our
best means of getting nitrogen from the air, it provides a large amount
of organic matter, it feeds in subsoil as well as in top soil, bringing
up fertility and filling all the soil with roots that affect physical
condition favorably, and it provides a feed for livestock that gives a
rich manure.
Pleasant, W. Va.]