ABSTRACT
Land is tilled to put the soil into proper physical condition for the germination of seeds and growth of crop roots, to incorporate green manures and other residues into soil, to mix manures, composts, and fertilizers into soil, and to control weeds. Tillage also helps in aeration and in drying and warming of soil. Shallow tillage can create a dust mulch that aids in water conservation. Tillage will shred and bury weeds or cut them at the soil surface so that the weeds are destroyed. Tillage has effects on control of pests other than weeds. Aeration of soil after tillage may aid in control of diseases. Tillage can bury disease-infested organic matter into the soil where diseases will die from unfavorable habits or be outcompeted by other soil-born organisms. Tillage exposes soil-borne insects to adverse conditions where they are vulnerable to predators, freezing, and desiccation. Tillage will bury insects from the surface of soil into the zones of the soil where it is impossible for the pests to survive.
