Soil Inoculation
Categories:
ORGANIC MATTER
The belief that the right kind of bacteria may be
absent from the soil when a new legume is seeded, and that they should
be supplied directly to the soil, has failed in ready acceptance
because examples of success without such inoculation are not uncommon.
Even if the explanation of such success is not easy, the fact remains
that legumes new to a region usually fail to find and develop a supply
of bacteria adequate for
a full yield, and some of these legumes, of
which alfalfa is an example, make a nearly total failure when seeded
for the first time without soil inoculation. Experiment stations and
thousands of practical farmers have learned by field tests that the
difference between success and failure under otherwise similar
conditions often has been due to the introduction of the right bacteria
into the soil before the seeding was made.
Explanations offered for any phenomenon may later become embarrassing
in the light of new knowledge. We do not really need to know why an
occasional soil is supplied with the bacteria of a legume new to it. We
have learned that the bacteria of sweet clover serve alfalfa, and this
accounts for the inoculation of some regions in the east. We believe
that some bacteria are carried in the dust on the seed, and produce
partial inoculation. Other causes are more obscure. The cowpea trails
on the ground, and carries its bacteria more successfully than the
soybean. Most legumes require a soil artificially inoculated when
brought into a new region, failing otherwise in some degree to make
full growth.