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.