【摘要】 临界氮稀释曲线可诊断植株氮营养状况,针对国内目前普遍存在的建模品种单一,可能造成模型普适性偏差的问题,以陕西关中平原主栽的6个冬小麦品种为研究对象,分别设置4个(0、105、210 kg·hm^-2和315 kg·hm^-2)施氮量水平,以两季4个冬小麦品种田间数据,建立了冬小麦花期前地上部干物质临界氮稀释曲线,曲线服从负幂指数函数;进一步通过另外2个冬小麦品种共计两季数据对模型进行了验证,验证结果表明,采用临界氮稀释曲线可以较好地区分独立样本中的氮营养亏缺和氮营养过剩数据。依据临界氮稀释曲线建立的氮营养指数和累计氮亏缺模型,可分别用于诊断植株的氮营养状况和量化氮素盈亏量,诊断结果表明施氮量为0 kg·hm^-2和105 kg·hm^-2条件下植株氮营养亏缺,210 kg·hm^-2和315 kg·hm^-2条件下小麦氮营养盈余,0～315 kg·hm^-2施氮量下的累计氮亏缺量-33.2～50.9 kg·hm^-2。通过建立氮营养指数与施氮量之间的线性关系,得出关中平原冬小麦适宜施氮量约为162 kg·hm^-2。更多还原

【Abstract】 The critical nitrogen concentration can be used to diagnose the crop nitrogen status. At present most domestic researchers only establish the curvefor a single variety. However, establishing a universal curve based on multiple varieties can significantly improve the application of the model. Six popular varieties of winter wheat and four nitrogen levels N₀（0）、N₁(105 kg·hm^-2)、N₂(210 kg·hm^-2)and N₃(315 kg·hm^-2)were applied in this study. The critical nitrogen dilution curveand the accumulated nitrogen deficit model were constructed based on the aboveground dry matter from re-growth to heading stages, and the results were compared with published N_c curves. The relation ship between maximum above ground dry matter and critical N concentration of winter wheat could be described in the form of negative power function. The nitrogen nutrition index and accumulated N deficit model were further derived from the critical nitrogen dilution curve, which can be used to evaluate the nitrogen nutrition status and quantify the N deficit of winter wheat, respectively. Results show that the nitrogen nutrition index increases with the N application rate. N₀ and N₁ nitrogen application rates showed nitrogen nutrition deficiencies, but nitrogen nutrition surplus was revealed in the N₂ and N₃ treatments. When nitrogen application rate was 0～315 kg·hm^-2, the accumulated N deficit(N_and) ranged from-33.2 kg·hm^-2 to 50.9 kg·hm^-2, and increased as winter wheat grew. Through the linear fitting between NNI and N application rates, a suitable N rate of about 162 kg·hm^-2 was obtained for winter wheat in Guanzhong Plain.更多还原