冬小麦冠层光谱红边特征分析

Red-edge characteristics of winter wheat canopy spectra

通过对不同N素营养水平冬小麦冠层光谱特性的田间试验研究，发现红边位移现象：在孕穗期前，红边随施N量增加向长波方向“红移”；孕穗期后“红移”现象基本消失，继而发生“蓝移”。红边参数中红边斜率（dλred）与叶片N累积量（TN．D）、叶绿素含量（CHL．T）、叶绿素密度（CHL．D）的相关关系通过显著性检验，红边面积（∑dλ680-760）和叶片全N含量（N％）的相关关系通过显著性检验，红边位置（λred）、红边斜率、红边面积与叶面积指数有着密切关系，均通过极显著性检验，一些红边参数可作为小麦农学参数估测的简便方法。

Winter wheat canopy spectral reflectance was field measured using spectrometer Field Spec at different nitrogen levels and time periods. Some red-edge parameters including wavelength （λred）,amplitude （dλred） and red-edge apex area （∑dλ680- 760）were analyzed for winter wheat leaf chlorophyll （CHL. T）, leaf nitrogen content（ N % ）, leaf area index （LAI） ,accumulated leaf nitrogen content（TN. D）, etc. It is found that red-edge positions move to long wavebands till booting stage and then fall back to short bands after booting. A significant correlation is found between dλred and TN. D, CHL. T, and CHL. D. Similar relation exists between ∑dλ,680 - 760 and N %. Red-edge parameters show strong correlation with LAI. It is thus concluded that some red-edge parameters form part of the best remote sensing descriptors.