WATER-USE PATTERN AND PRODUCTIVITY OF RAIN-FED YELLOW SARSON (BRASSICA-RAPA L VAR GLAUCA) IN RELATION TO TILLAGE AND MULCHING

Field experiments were conducted during 1983-1989 to 1990-1991 on a sa ndy loam (Typical ochraqualf) soil of eastern India, to determine the effects of four mulch types: (no mulch; soil dust mulch; green mulch a t 20 mg ha(-1); and rice straw mulch 5 mg ha(-1)); and three tillage t reatments (two, four and six ploughings to 100 mm depth) on profile wa ter conservation, grain yield and water use efficiency (W-ue) of rainf ed yellow sarson (Brassica rapa L, var glauca). Green and dry straw mu lches conserved 15% and 13.7% more water than the no mulch treatment i n the top 500 mm of the soil profile. As compared with the no mulch co ndition, grain yield was increased by 47%, 43% and 16% respectively un der green, straw and soil dust mulching, Besides vegetative mulches, s oil dust mulch also increased the W-ue, of the crop. Grain yield and W -ue were not significantly changed by an increase in the number of plo ughings from two to six.