Response of aerobic rice (Oryza sativa) to different irrigation regimes and nitrogen levels in western Odisha

A field experiment was conducted during the summer seasons of 2013 and 2014 at Chiplima, Odisha, to deter- mine the effect of irrigation regimes and nitrogen (N) levels on yield, field water-use efficiency (FWUE) and eco- nomics of APO cv. of aerobic rice (Oryza sativa L.). The treatments consisted of 4 irrigation regimes (irrigation at 3, 5, 7 and 9 days intervals) in the main-plots and 4 levels of nitrogen (0, 40, 60 and 80 kg N/ha) in the sub-plots, replicated thrice. The pooled mean results revealed that maximum grain yield (3.44 t/ha) and benefit: cost ratio (1.40) were obtained when irrigation was provided at 3-day interval. However, the both the parameters obtained with irrigation being provided at 5-day interval were at par with their maximum values. The field water-use effi- ciency was the maximum with irrigation at 7-day interval (36.01 kg/ha-cm) which was at par with irrigation at 5-day interval (34.48 kg/ha-cm). With regards to N level, application of 80kg N/ha recorded significantly higher grain yield (3.58 t/ha), FWUE (40.55 kg/ha-cm) and benefit: cost ratio (1.48) than that of other N levels. Thus, economi- cally higher grain yield, FWUE and benefit: cost ratio were obtained when crop was irrigated at 5-day interval and fertilized with 80 kg N/ha.