本文以杂交水稻为对象,研究其对不同氮素水平的反应,及对氮素吸收利用的内在规律,探求省肥高产的途径。一、试验设计与方法试验共进行三年。1977年在浠水县十月大队进行田间试验,采用L_8(4×2~4)设计,氮肥用量为主因子,分四个水平,即每亩施纯氮3斤、10斤、17斤、24斤。其它因子为氮肥用期、用法及磷、钾肥用量均为两水平。小区面积150尺~2,重复3次,随机区组排列。1979年采用氮肥用量单因子土培试验设计,每盆用硫铵4 (低氮)、8 (中氮)、 In this paper, the hybrid rice as an object, to study its response to different levels of nitrogen, and nitrogen absorption and utilization of the inherent law, to explore ways to save fertilizer and high yield. First, the experimental design and method of testing a total of three years. 1977 in Xishui County October field trials, using L_8 (4 × 2 ~ 4) design, the amount of nitrogen as the main factor, divided into four levels, that is, per acre applied nitrogen 3 pounds, 10 pounds, 17 pounds, 24 pounds. Other factors for the period of nitrogen fertilizer, usage and phosphorus, potassium fertilizer levels are two levels. Area of ​​150 feet ~ 2, repeated 3 times, random block arrangement. In 1979, nitrogen fertilizer was used to design single factor soil culture experiment. Each pot was treated with 4 (low nitrogen), 8 (medium nitrogen)