高土壤肥力环境下不同类型粳稻品种产量对氮肥用量的响应

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。

Response of Grain Yield of Different Japonica Rice Cultivars to Amount of Nitrogen Application in High-Fertility Paddy Field

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.