关中冬小麦叶片氮素含量高光谱遥感监测模型

Monitoring Model of Leaf Nitrogen Content of Winter Wheat in Guanzhong District by Hyperspectral Remote Sensing

为给黄土高原大范围的冬小麦氮素营养遥感监测提供理论依据,通过田间试验,研究了冬小麦叶片氮素含量遥感监测的最佳生育时期、最敏感波段及其他最优光谱参量。结果表明,灌浆期是利用高光谱遥感监测冬小麦叶片氮素营养状况的最佳生育时期;在拔节、抽穗和灌浆期680nm波段光谱反射率R680均能较好地反映冬小麦叶片氮素含量,基于光谱位置以及叶面积指数的光谱参量也能较好地反映冬小麦叶片氮素含量。拔节期、抽穗期和灌浆期分别以680nm波段光谱反射率R680、绿峰反射率Rg和植被指数(SDr-SDb)/(SDr+SDb)对小麦叶片氮素含量的拟合效果最佳,其回归方程分别为Y=27.54-280.247 X+1456.245 X2、Y=8.632 X-0.24和Y=25.83 X1.012。

Hyperspectral remote sensing is a new approach for quick,nondestructive and reliable monitoring of crop nitrogen nutrition.A field winter wheat nitrogen nutrition monitoring experiment for hyperspectral remote sensing with different nitrogen application treatments was conducted in Guanzhong district,Shaanxi to explore the best growth period,sensitive waveband and other spectral parameters of hyperspectral remote sensing to diagnosis leaf nitrogen content of winter wheat.The results showed that grain filling stage was the most appropriate stage for diagnosis wheat leaf nitrogen content by hyperspectral remote sensing and the waveband of R680 could be used to leaf nitrogen content at jointing,heading and grain filling stage of wheat growth.The index based on position of the spectrum and leaf area can also predict leaf nitrogen content of winter wheat precisely.The best wheat leaf nitrogen content regression equation based on spectral reflectance of 680 nm waveband at jointing stage was Y=27.54-280.247X＋1456.245X2,R2=0.832;and the best wheat leaf nitrogen content regression equation based on spectral reflectance of green peak at heading stage was Y=8.632X-0.24,R2=0.882;the best wheat leaf nitrogen content regression equation based on vegetation index of（SDr-SDb）/（SDr＋SDb） at grain filling stage was Y=25.83X1.012,R2=0.860.