No-till: better soil at less cost

One sure way of reducing soil degradation is to cut down on tillage. Numerous crops can be grown using the no-till approach, and many farmers who have done so will testify that it cuts costs and improves rain penetration in the soil. The soil also holds more water; in fact, no-till soils generally show drought stress two weeks later than tilled soils do.

There is, however, one important requirement for no-till farming: you need to grow a legume in rotation on the land. Soya bean is usually the preferred option.

The reason for this is that a leguminous crop such as soya bean captures nitrogen (N). Without it, there would not be enough N to maximise the conversion of carbon (C) in the crop residue to humus.

You can have tons of crop residue, but if there isn’t enough N in the soil, the residue will simply evaporate as carbon dioxide.

One ton of crop residue contains about 400kg of C, of which 140kg can be converted to humus. The balance is lost to the atmosphere through metabolism of the soil microbes.