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田间条件下,对皖稻52和宁粳3号在不同施氮水平(0、60、120、180、240和300 kg·hm-2)下的产量、氮素吸收、累积及利用率进行研究。结果表明,施氮量超过180 kg·hm-2后,水稻产量增加较少,超过240 kg·hm-2,水稻产量开始下降。当施氮量从60 kg·hm-2增加到300 kg·hm-2,皖稻52和宁粳3号的氮肥表观利用率(REN)分别为75.1%~49.4%和62.1%~50.2%;氮肥农学利用率(AEN)也随施氮量的增加而显著下降,为17.3~7.33 kg·kg-1和16.8~8.64 kg·kg-1。通过拟合水稻产量、经济效益与施氮量的回归方程计算,水稻皖稻52和宁粳3号的最大经济效益施氮量分别为178 kg·hm-2和190 kg·hm-2。此时,水稻可维持较高的产量和保持较高的氮肥利用率。
Under field conditions, the yield, nitrogen uptake, accumulation and utilization of Wandao 52 and Ningjing 3 at different N rates (0, 60, 120, 180, 240 and 300 kg · hm-2) . The results showed that when the nitrogen application rate exceeded 180 kg · hm-2, the rice yield increased less than 240 kg · hm-2, and the rice yield began to decline. The apparent nitrogen use efficiency (REN) of Wandao 52 and Ningjing 3 were 75.1% -49.4% and 62.1% -50.2%, respectively, when the nitrogen application rate increased from 60 kg · hm-2 to 300 kg · hm-2. ; Nitrogen utilization rate (AEN) also decreased significantly with the increase of nitrogen application rate, ranging from 17.3 to 7.33 kg · kg-1 and from 16.8 to 8.64 kg · kg-1. The maximum economic benefit of applying Wandao 52 and Ningjing 3 were 178 kg · hm-2 and 190 kg · hm-2, respectively, by fitting the regression equation of rice yield, economic benefit and nitrogen application rate. At this point, rice can maintain a higher yield and maintain high nitrogen use efficiency.