Effects of irrigation regime and nitrogen management on grain yield, quality and water productivity in rice

Increasing water scarcity necessitates the development of irrigated rice systems that require less water than traditional flooded rice. Effects of different water regimes on grain yield, quality and water productivity in rice under nitrogen management were studied using a variety of Liangyoupeijiu in a field. Cultivar Liangyoupeijiu was grown under traditional flooding (TF), alternately wetting and drying irrigation (AWD) and raised-bed cultivation (RBC) at four N rates (0-270 kg N ha -1 in 90 kg increments, expressed as N 0 , N 90 , N 180 and N 270 , respectively). Three water regimes treatments were arranged in a split plot design with three replications. Water regimes were the main plots, and four nitrogen levels were used as subplots. There were significant differences in rice grain yield, quality and water productivity under different water regimes with various nitrogen rates. AWD and RBC increased grain yield by 2.5% and 9.1%, improved water productivity by 28.9% and 32.2%, respectively, compared with that under TF. Milling quality traits such as brown rice rate (BRR) were improved significantly under AWD and RBC. Significant interactions between irrigation regimes and N rates were also observed in panicle number per square metre, Chalky percentage (CP) and chalkiness values (CN) of grain. The grain yield under N 180 was increased by 45.4% under TF, 65.2% under AWD and 38.4% under RBC, respectively, compared with that under N 0 . The results suggest that AWD and RBC would be better practices than TF in some areas in China where water is scarce.