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作 者 ：张秀芝 易琼 朱平 何萍 杨利 范先鹏 熊桂云

期 刊 ：植物营养与肥料学报 2011年 17卷 4期 页码：782-788

关键词：氮肥量级；SPAD值；氮肥利用率；氮平衡；

Keywords:Nitrogen application level, SPAD value, N fertilizer use efficiency, N balance,

摘 要 ：通过田间试验，以不同氮肥量级为参照，结合关键生育期叶片叶绿素含量（SPAD值）指导氮肥施用，以探明潜江地区水稻关键生育期的氮肥适宜用量。结果表明，在施N 90～180kg/hm2间水稻产量差异不显著，当超过N 180 kg/hm2，产量降低。根据水稻产量（y）和施氮量（x）拟合得出一元二次关系式：y = -0.0728x2 + 22.335x + 6811.5，R2 = 0.9442。结合当年水稻价格肥料投入费用等计算出水稻的经济效益（Y）和施氮量（X）之间的函数式：y = -0.134x2 + 37.097x + 12533-M，R2 = 0.9331；由此得出经济效益最大时水稻的施氮量是N 138 kg/hm2。该施氮量下水稻的氮肥表观利用率，农学利用率和氮肥偏生产力可保持在40.9%，11.5 kg/ kg和63.2 kg/ kg，与完全依据SPAD值指导关键生育期的氮肥施用量相近似（N 140 kg/hm2），保证了水稻最大的经济效益，同时也保持了较高的氮肥利用率，降低氮素表观损失。

Abstract:Field experiments were conducted to explore the optimum N application rate based on agronomic responses to different N application rates, and the leaf SPAD values at the critical growth stages were measured for guiding the N management practices in the Qianjiang region. The results indicate that there are no significant differences in grain yield when N application rates range from 90 to 180 kg/hm2, while grain yield is decreased when N rate is over 180 kg/hm2. The equation between grain yield of rice and N application rate is established: y=-0.0728x2+22.335x+6811.5，R2=0.9442. Then the economic optimum nitrogen rate (EONR), 138 kg/ha, is evaluated in the study area by the equation between economic benefit of rice and N application rate (y=-0.134x2+37.097x+12533-M，R2 = 0.9331) based on the input of N fertilizer and output of grain yield, and the N recovery efficiency, agronomic efficiency and N partial factor productivity are 40.9%，11.5 kg/kg and 63.2 kg/kg, respectively. The produced N application rate (140 kg/ha) guided by SPAD values at the critical growth stages is matched perfectly with EONR under the maximum economic benefit, higher nitrogen use efficiency and low nitrogen apparent loss.

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