Abstract:

This study was conducted to compare the yield and N use efficiency in two popular rice varieties under different N fertilizer rate. Japonica cultivar Liaoxing 1 and japonica hybrid cultivar Liaoyou 5238 were grown under seven N treatments in 2008. The results showed that the application of N fertilizer could improve the rice yield. However, the improving range decreased obviously with the increase of N fertilizer applied amount. When the nitrogen fertilizer was applied at 15kg N/667m2, both Liaoxing 1 and Liaoyou 5238 got the highest economic returns among the treatments, and the outputs reached 636.7kg/667m2 and 637.3kg/667m2, respectively. The total amount of nitrogen accumulation in rice increased, but the nitrogen physiological efficiency, agronomic efficiency, partial factor productivity, nitrogen dry matter production efficiency and nitrogen grain production efficiency reduced with the increase of N fertilizer application rate. We also found that Liaoyou 5238 had strong ability to absorb nitrogen and transform nitrogen to grain under lower N fertilizer applied amount treatments, and, even if less fertilizer was applied for Liaoyou 5238, it would get the same yield level to Liaoxing1.