Implications of no-tillage versus soil preparation on sustainability of agricultural production

The key problem of tropical agriculture is the steady decline in soil fertility, which is closely correlated to duration of soil use. This is due primarily to soil erosion and the loss of organic matter associated with conventional tillage practices, that leave the soil base and unprotected in times of heavy rainfall and heat. The implications of soil preparation on soil erosion and the sustainability of agricultural production was studied with special reference to experience and projects carried out in Paraguay, Brazil and Argentina under tropical and subtropical conditions. Scientific data show that under tropical and subtropical conditions, tillage generally has a detrimental effect on chemical, physical and biological soil properties. Investigations also show that erosion damage is enhanced when the soil is bare. Water infiltration rates are increased and consequently erosion is reduced when mulch covers the soil in a no-tillage system. Tillage also. releases considerable amounts of CO2 into the atmosphere contributing to global warming. In order, to achieve sustainable agriculture in the tropics and avoid global warming, soil tillage has to be reduced to a minimum or avoided completely and the soil has to stay as long as possible covered with mulches, sod and growing crops. No-tillage in mulches of previous crops or green manures in combination with adequate crop rotations is the production system of the future if sustainable agriculture is to be achieved.