Soil Conservation

Abstract

Tillage serves to improve soil conditions in relation to the water balance and crop growth, to incorporate crop residues, to control weeds and to prepare the seedbed. However, tillage significantly increases the risk of soil erosion. These problems have led to the development of conservation tillage techniques which typically rely on the maintenance of plant residues on the ground and in a substantial reduction in tillage operations. When conservation tillage is combined with the use of crop rotations is termed conservation agriculture. Conservation tillage requires the use of herbicides and specific direct drills for crop sowing. The transition from conventional to conservation tillage should be gradual as additional problems may arise (e.g. compaction) in some soil types. Sporadic tillage or controlled traffic could then be adopted. In tree orchards many options for soil management are available, from conventional tillage to the no-tillage with bare soil and herbicide applications. A particular case is that of rain fed tree orchards in Mediterranean areas, whereas the problems of no-till (gully erosion, reduced infiltration) can be partially alleviated by temporal cover crops that protect the soil during the rainy season and are killed in early spring to avoid competition for water with trees.