THE LONG TERM EFFECT OF NO-TILL

By Jim Kensella, Lexington, IL

After the transition period which may require three to six years depending on the soil and conditions, many benefits to both soil and the environment will begin to accrue with a well managed continuous no-till system.

With increasing years without tillage the soil structure and tilth will improve and the organic matter will begin to increase. Earthworm populations will increase dramatically in most soils and the microbial activity should also increase substantially. Soybeans or other legumes are important in a no-till rotation to provide high protein residue to feed the increase biological activity. As the micro and macro porosity of the soil improves with time in no-till, water infiltration will increase dramatically. Nutrient availability will usually increase with time in a continuous no-till system. The immobile nutrients such as P, K, and Ca will be less likely to be moved by the force of erosion. Nitrogen availability should increase because of increasing organic matter, and greater in season microbial mineralization.

Annual weed pressure will generally decrease while perennial and winter annual weed pressure will increase over time without tillage. A shift in weed control materials and timing may be required, but this usually does not result in more active ingredients per acre than on a typical tilled farm.

In general, diseases shift from more of a hot/dry soil borne type complex, to a more cool/wet residue borne complex. Crop rotation and/or genetic rotation is recommended for continuous no-till.

Insect potential may also shift in a continuous no-till system. Some residue or weed attracting insects such as cutworm or corn bore may increase but other insects such as corn rootworm may decrease in severity. Rodents may become a greater problem but nematodes appear to be less adapted to continuous no-till.

If managed properly, a switch to continuous no-till farming has many more benefits than liabilities. By improving the efficiency of crop production while reducing the negative impacts to the environment. Farming without tillage appears to be developing as a mega trend in world wide agriculture.