INFLUENCE OF IRRIGATION ON YIELD, PROFILE MOISTURE USE, WATER-USE EFFICIENCY AND NET RETURN OF WINTER MAIZE (ZEA-MAYS) AND POTATO (SOLANUM-TUBEROSUM) INTERCROPPING

An experiment was conducted during 1987-90 with 5 irrigation treatment s based on irrigation water depth : cumulative pan evaporation (IW : C PE) ratios with sole crops of maize (Zea mays L.) and potato (Solanum tuberosum L.) and their intercropping. In maize alone, maize-equivalen t yield was maximum (5.38 tonnes/ha) at an IW : CPE ratio of 1.0, wher eas in sole potato and in its intercropping with maize a significant i ncrease(11.25 and 13.34 tonnes/ha respectively) was recorded up to an IW : CPE ratio of 1.2. Net return was maximum up to an IW : CPE ratio of 1.0 in sole crops of maize (Rs 6937/ha) and potato (Rs 12684/ha), w hereas in intercropping stands maximum (Rs 15398/ha) net return occurr ed at an IW : CPE ratio of 1.2 with 7 irrigations. Water-use efficienc y was maximum at an IW : CPE ratio of 0.8 in sole crops of maize and p otato, and at 0.6 in the mixed crops. Soil-moisture depletion was more (42.22 mm at 1.2 ratio) from the 0-60 cm layer in the intercropped th an that in pure crop of either maize (32.25 mm at 1.2 ratio) or potato (13.89 mm at 1.2 ratio).