用冠层反射光谱预测小麦叶片糖氮量及糖氮比

在不同土壤水氮条件下，研究了小麦中后期叶片碳氮状况及其比例与冠层光谱反射特征的关系。结果表明，叶片可溶性糖含量和积累量均随比值指数R(660, 460)的增加而降低，呈极显著负指数相关，而与其他植被指数相关不显著；叶片氮含量和氮积累量分别与比值指数R(950, 710)和R(950, 560)呈极显著正直线相关。发现小麦叶片糖氮比

Monitoring Soluble Sugar, Total Nitrogen & Its Ratio in Wheat Leaves with Canopy Spectral Reflectance

The research was conducted to determine the relationships of sugar and nitrogen status and its ratio in wheat leaves to canopy spectral reflectance under different nitrogen and water supply levels. The results showed that there were negative exponential relationships of soluble sugar content and accumulation to ratio index R(660,460), but no significant relationships with other vegetation indices; and there were positive linear relationships of leaf nitrogen content and accumulation to ratio index R(950,710) and R(950,560) in wheat leaves. In addition, green soil-adjusted vegetation index (GSAVI) was found to be parabolically related with sugar to nitrogen ratio (S/N) in wheat leaves, with the RMSE of 0.11 for model testing, although no significant correlations were found between S/N and other vegetation indices, such as ratio index, normalized index and difference index. The present results indicate that the GSAVI should be a good indicator to evaluate leaf S/N ratio in wheat.