在五个施肥水平下，探讨了6个品种氮肥的农学利用率、稻谷产量以及米质的差异。研究表明，随着施氮量的增加，产量升高。不同施肥水平下，对氮肥的农学利用率不同，75、150kg/hm2施肥水平下较高。随着施氮量的增加，氮肥的农学利用率下降。因此，降低施肥量可以提高氮肥的农学利用率。不同品种在不同的氮肥水平下表现也不相同：协优57在75kg/hm2施肥水平下的农学利用率最高，达14.6Kg稻谷/kg氮；氮肥农学利用率高的品种也需在适宜的施肥水平下才能体现。试验还得出：在不同的产量目标下，可选择不同的品种，以达到目标。而无论在何产量目标下，以选择协优9019风险最小。因为它的平均氮肥农学利用率较高。多产稻和汕优63是较耐低肥的品种。从改善米质来讲，150kg/hm2的施氮量较为有利。

Research on the difference of the fertilizer-N agronomic use efficiency (AEN), grain yield and the rice quality by using six varieties under five levers of N-fertilized. Results showed that the grain yield was improving with the amount of the N-fertilized increasing. Under the different levers of N-fertilized, the AEN were difference. The AEN was decreasing with the amount of the N-fertilized increasing. But, different varieties have a different result under the different levers of N-fertilized. The AEN of the Xieyou 57 was the highest under the lever of 75 Kg N-fertilized. At the difference yield objects, the object could be achieved by using the difference varieties. But, the risk of Xieyou 9019 was the lest. Because its average AEN was the highest. Duochandao and the Shanyou63 were the varieties, which could endure the lower lever of N-fertilized. At the amount of 150Kg N-fertilized, the rice quality could be improved.