本试验通过三年多点田间试验,研究了大豆施氮肥的增产效果。结果表明,不论高量或低量均有增产,但N_3增产最多、最稳、效益最好。施氮肥对地上部(株高、鲜重、叶面积系数等)生长有良好的促进作用,而氮用量、地上部生长量和产量之间无明显回归关系。氮肥对根部生长影响显著。施氮肥使根瘤量平均减少24.2％,使固氮酶活性平均降低61.25％。 In this experiment, more than three years of field trials to study the effects of soybean nitrogen fertilizer production. The results showed that no matter high or low yield increase, but N_3 yield the most, the most stable, the best benefit. Nitrogen fertilizer had a good effect on the growth of above-ground parts (plant height, fresh weight and leaf area coefficient), while there was no obvious regression relationship between nitrogen application, shoot growth and yield. Nitrogen fertilizer had a significant effect on root growth. Nitrogen fertilizer reduced nodulation by 24.2% on average, and decreased nitrogenase activity by 61.25% on average.