中文摘要：

基于3年的大田试验，选择代表性的中蛋白小麦品种（扬麦16）和低蛋白小麦品种（宁麦13），分别构建了小麦地上部干物质临界氮浓度（Ncnc）稀释曲线模型、氮营养指数（NNI）模型和氮亏缺（N_and）模型．结果表明：小麦地上部干物质临界氮浓度稀释曲线模型具有明确的生物学意义，小麦临界氮浓度与地上部最大干物质（DM）符合幂函数关系（扬麦16为Ncnc=4．65DM^-0.44；宁麦13为N_cnc=4．33DM^0.45）；小麦地上部氮营养指数模型可以准确诊断氮素营养状况；小麦地上部氮亏缺模型可以定量调控氮肥管理措施．利用2007--2008年的独立试验资料对小麦地上部干物质临界氮浓度稀释模型、氮营养指数模型和氮亏缺模型进行检验和测试，结果表明模型的准确性较高，普适性较强．本文所构建模型可以直接用于诊断调控小麦氮素营养，为小麦生产中精确施肥管理提供了较好的技术途径和理论基础．

英文摘要：

Based on three-year field experiments, three models of critical nitrogen concentration di- lution curve, nitrogen nutrition index, and accumulative nitrogen deficit were constructed for the aboveground dry matter in medium protein wheat variety Yangmai 16 and low protein wheat variety Ningmai 13, respectively. The critical nitrogen concentration dilution curve model had specific bio- logical meaning, i.e. , there existed a negative power function correlation between shoot maximum dry matter （ DM ） and critical nitrogen concentration （ N_cnc ） （ Yangmai 16 ： N_cnc = 4. 65DM^-0.45 ; Ningmai 13 ： N_cnc =4.33DM^-0.45 ）, the nitrogen nutrition index model could be used for accurate di- agnosis of wheat plant nitrogen status, and the accumulative nitrogen deficit model could be used for quantitative regulation of nitrogen fertilizer management. The tests of the derived equations with in- dependent experiment data （2007-2008） showed higher accuracy and reliable prediction, sugges- ting that the present models could be used for the diagnosis and regulation of wheat nitrogen nutri- tion, providing a key technical approach to precise fertilization management in wheat production.