摘 要 ：以13个粳稻品种为材料, 设计5种氮肥用量, 研究高肥环境下氮肥用量对粳稻产量及其构成的影响, 并比较不同产量、结实率、每穗粒数、千粒重和穗数水平粳稻品种对氮肥的响应。结果如下: (1) 粳稻产量以施氮处理显著高于不施氮处理, 多数粳稻品种在施氮量为150~225 kg hm-2时产量最高; 每穗粒数和有效穗数随施氮量的增加而增加, 但当施氮量超过225 kg hm-2时反而下降, 而千粒重和结实率随施氮量的增加一直呈下降趋势。(2) 氮肥对不同产量水平、穗数水平粳稻品种的增产效应不同。不施氮时产量越低的粳稻品种对氮肥越敏感, 少量施用氮肥即起到较好的增产效果, 而不施氮时产量越高的粳稻品种对氮肥相对钝感, 氮肥施用量<75 kg hm-2时对其产量无明显促进作用。穗数<220×104穗 hm-2和>310×104穗 hm-2的粳稻品种的适宜施氮量低于穗数居中的粳稻品种。(3) 1980年以前育成的品种对氮肥的反应相对一致, 多数在施氮量225 kg hm-2时产量最高; 而1980年后育成的粳稻品种最高产时的N水平相对分散。
Abstract:Nitrogen is the most important nutrition in rice production, and its function is affected by cultivar, fertilizer application and soil condition. In resent years, paddy field in Yangzi River has a trend of becoming fertile. In order to identify the optimal nitrogen application amount in high-fertility paddy field and to study the cultivar difference in nitrogen requirement, we planted 13 japonica rice cultivars with 5 nitrogen application levels in a high-fertility paddy field in China National Rice Research Institute, Zhejiang province. The results were as follows: (1) Rice yield was significantly increased by nitrogen, most japonica rice cultivars reached their highest yield when nitrogen was applied at 150–225 kg ha-1. With the increase of nitrogen application amount, 1 000-grain weight and seed setting rate decreased, while grains per panicle and effective panicle number increased till nitrogen application amount reached 225 kg ha-1. (2) There existed cultivar difference in optimal nitrogen application amount. According to the cultivar yield characteristics in none-nitrogen application treatment, low-yielding japonica rice cultivars were sensitive to N fertilizer, their yield increased largely even when small amount N fertilizer was applied, while the yield of high-yielding cultivars changed little when applied N fertilizer < 75 kg ha-1; the optimal nitrogen application amount of cultivars with middle panicle number was larger than that with low (< 220×104 per hectare) and high (< 220×104 per hectare) panicle number. (3) Most of the cultivars released before 1980 had the highest yield when 225 kg ha-1 nitrogen was applied, while the nitrogen needed for the highest yield in cultivars released after 1980 was different.