杂交稻施氮水平效应研究

The Effect of Nitrogen on Grain Yield of Hydrid Rice

历经３ａ设置不同施Ｎ水平试验，结果表明：杂交稻的吸Ｎ量随施Ｎ水平的提高而呈曲线增加，但Ｎ肥回收率和生产干物质及稻谷的效率随施Ｎ水平的提高而降低。干物质积累量、稻谷产量与施Ｎ量呈抛物线型相关。试点施Ｎ１３０～１４４ｋｇ／ｈｍ２可保持较高的Ｎ肥回收率和生产效率，取得最高的产量和经济效益。提出杂交稻主要生育期叶片含Ｎ率的高产诊断指标为分蘖期４．３％～４．５％，苞分化期３．７％～４．１％，齐穗期２．８％～２．９％，黄熟期１．４％～１．５％。

The experiment was conducted in Longhai ,Fujian,China during 1991-1993.Results showed that the relationship between nitrogen absorbed by rice plant and amount of nitrogen fertilizer applied appeared as a curve;The nitrogen use efficiency of rice plant was decreased when the amount of nitrogen applied increased;However,both of the accumulation of dry weight and grain yield of hybrid rice showed as parabola related to the rate of nitrogen applied;The optimum rate of nitrogen for hybrid rice in Longhai was about 130-144 kg N/hm2;The nitrogen contain in leaf at different growing stages was an important index for obtaining higher grain yield of hybrid rice.Those indexes were 43%-45%,37%-41%,28%-29% and 14%-15% at tillering,panicle initiation,heading and maturing stage,respectively.