氮肥对水稻产量和氮肥利用率的影响

探讨不同氮肥水平对常规稻和杂交粳稻产量和氮肥利用率的影响。试验于2008年在大田条件下进行，以辽星1号和辽优5238为供试材料，研究了不同氮肥水平处理下供试品种产量及氮肥利用率的变化。结果表明，水稻产量随施氮量的增加而增加，但增产幅度明显下降。氮肥施用量为15kgN/667m2，辽星1号和辽优5238的产量分别为636.7 kg/667m2和637.3 kg/667m2，达到较高的经济效益。随着氮肥施用量的增加，水稻吸收氮素的总量提高，氮素生理利用率、农学利用率、氮肥偏生产力、氮素干物质生产率和氮素稻谷生产率随之降低。在低氮水平下，辽优5238有较强的氮素吸收能力以及向籽粒转化运输的能力，并且同一产量水平下，辽优5238比辽星1号更省肥。

Effect of N Fertilizer on the Yield and Nitrogen Use Efficiency in Rice

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.