棉花冠层反射光谱与叶片氮含量定量关系研究

Relationships between Leaf Nitrogen Content and Canopy Reflected Spectral in Cotton

对可见光波段至短波红外波段（350～2500nm）棉花田间冠层光谱反射率与叶片含氮量间的关系进行了相关分析。结果表明，350～732、733～940和1970～2477nm波段的光谱反射率与叶片含氮量极显著相关；940～1176nm波段的光谱反射率与叶片含氮量显著相关。以上波段为叶片全氮敏感波段。通过分析叶片含氮量与高光谱特征参数关系，得出吸收谷特征参数Depth1154和PRI（570，530nm）可以用来预测盛花期叶片含氮量，其中Depth1154的复相关系数最高达到0．7473，为运用遥感技术大面积、迅速、无破坏地来预测棉花生长状况以提供可能。

The field spectra reflectance data at key growth stages of cotton were analyzed. It indicated that the spectral reflectance of wave band bad significant correlation to leaf nitrogen content at 350 - 732,733 - 940 nm and 1 970- 2 477 nm. The proper spectral reflectance should be established for donating the spectral reflectance and leaf nitrogen content at different growth stages. Quantitative relationships of leaf nitrogen content and relevant quality traits to canopy reflectance was analyzed. The hyperspectral parameters were investigated in the experiments. The results showed that leaf nitrogen content could be predicted by depth 1 154 and PRI（570,530 nm） during flowering and full- blossoming. The quantitative relationships between leaf nitrogen concentration and depth of absorption valley （ VD1154） of canopy were significant different from an average R2 of 0. 7473. These results provided a theoretical basis and technical approach for monitoring of plant nitrogen status and precision management of nitrogen fertilization in cotton production.