叶绿素是农作物生长中重要的因素。叶绿素含量既表明作物生长的状况, 又表征了作物的生产能力。而叶绿素密度 (单位面积农作物的叶绿素含量)是估计农作物群体生产力的重要指标。对早播稻、晚播稻和玉米的多时相的群体光谱测量数据和相应的叶片叶绿素密度的测量数据进行了相关分析, 结果表明早播稻、晚播稻和玉米的群体光谱的反射率数据以及其导数光谱数据与叶绿素密度具有很好的相关性, 并且可以对这几种农作物建立统一的线性回归关系。利用这几种农作物的导数光谱在近红外波段 762nm处与叶绿素密度的高相关性, 选取样本建立了回归方程。并利用其余样本对估计方程进行检验, 结果表明估计的标准偏差为 0.2 72g/m², 估计精度约为 80.6 %。

The correlative relationship in the reflectance spectra, first derivative spectra of canopies and the chlorophyll content of early-planted rice, late-planted rice, and maize has been discussed. It shows that their correlative relationship is good, especially for the first derivative spectral data at the waveband 762 nm. Therefore, the same regression equation can be calculated for different crops. The linear regression equation has been built by using the first derivative spectral data of a part of samples at waveband 762 nm to estimate the chlorophyll content. Through the test of the other part of samples, it shows that the standard error is 0.272g/m², and the estimated accuracy is about 80%.