Effect of irrigation levels on yield, water-use efficiency and economics of winter maize (Zea mays)-based intercropping systems

A field experiment was conducted during winter season of 2002-03 and 2003-04 at Pusa in Bihar to study the effect of four irrigation levels, based on Irrigation water (IW): cumulative pan evaporation (CPE) ratio and four in- tercropping systems. The plant height, leaf-area index, yield attributes except number of cobslplant and grain yield of maize increased significantly with increase in IW:CPE ratio. Application of five irrigations each of 6 cm depth gave the maximum maize-equivalent yield, and net return1Re of investment. lntercroping of maize (Zea mays L.) reduced the maize yield but significant reduction was recorded only in french bean (Phaseolus vulgaris L.) and toria (Brassica campustris L. var. toria) intercropping system. However, water-use efficiency (WUE) de- creased with increase in IW:CPE ratio and was maximum at IW:CPE 0.6. Among the intercrops, maximum WUE (on the basis of maize-equivalent yield) was obtained with maize + potato (Solanum tuberosum L.) (561.89 kg1 ha-cm) and minimum with maize + toria (256.0 kglha-cm). All the intercrops with maize recorded significantly higher maize-equivalent yield than sole cropping of maize. Maize + potato recorded the highest (123.48 and 140.07 qlha) maize-equivalent yield and net return, whereas, sole cropping of maize recorded the maximum net return per rupee of investment. Among intercropping systems, maize+potato generated the highest net return (Rs 28,781 and 35,661), followed by maize + rajmash.