ABSTRACT

A narrow lip or soil bund along the outer edge is a valuable addition to rainfed terraces because it protects the terrace edge from damage by draft animals, and it prevents the planting of a row of crop whose harvesting will damage the edge. To reduce the damage from overland flow, the US Soil Conservation Service developed systems of contour plowing with the organization of surface drainage into grassed channels on a sub-watershed basis. Preparation of a seedbed for most cereals requires a bare soil with a loose tilth exposed to the heavy thunderstorms with which the tropical rainy seasons usually begin. Watershed boundaries rarely coincide with either farm boundaries or administrative divisions. The safe routing of runoff water, depends on the shape of the land and the location of the natural drainage lines; these lines may cross both farm and district boundaries.