水稻、玉米、棉花的高光谱及其红边特征比较

Comparison of the Characteristics of Hyperspectra and the Red Edge in Rice, Corn and Cotton

测定了水稻、玉米、棉花 3种作物共 6个品种的冠层和主茎叶片不同生育期高光谱反射率及其对应叶片中叶绿素、类胡萝卜素含量 ,分析了它们的高光谱及其红边特征和红边参数与叶面积指数、地上生物量、鲜叶重及叶片色素含量的相关性。结果表明 :(1) 3种作物冠层高光谱反射率大小与其生育期有关。冠层和叶片光谱反射率最大值比较结果是 ,冠层光谱 :棉花 >玉米 >水稻 ;叶片光谱 :水稻 >棉花 >玉米。 (2 ) 3种作物冠层光谱的红边都具有“双峰”现象。红边幅值Dλr 和红边面积Sr 均呈增大、减少的变化规律 ,但红边位置λr 的变化范围和变化规律不同 ;冠层红边参数λr、Dλr、Sr 与其叶面积指数和鲜叶重之间都呈极显著相关 ,但与地上鲜生物量和地上干生物量相关性有差异 ;叶片叶绿素a、叶绿素b、总叶绿素及类胡萝卜素含量与其光谱红边位置λr 之间都呈极显著相关 ,但与红边参数Dλr、Sr

The hyperspectral reflectances of the canopy, and the leaves on the main stem of six varieties in three crops were measured at different stages. The contents of chlorophyll and carotenoid of canopies and leaves corresponding to the spectra were determined. The characteristics of their hyperspectra and their red edge, the correlation between their red edge parameters and the pigment contents, leaf area indices, above ground biomass and fresh leaf mass were analyzed. The results showed that the canopy hyperspectral reflectance of three crops had relation to their growing stages. The maximum value of canopy spectral reflectance was the biggest for cotton and the smallest for rice, and that of leaves spectral reflectance the biggest for rice and the smallest for corn. There were 'double peak' phenomena for the red edge of canopy spectra in three crops. There were 'increase' and 'decrease' change rules for the red edge slope Dλ r and red edge area S r of the canopy spectra for three crops, but the change extents and rules for their red edge position λ r were different. The leaf area indices and fresh leaf mass were very significantly correlated to the red edge parameters λ r, Dλ r and S r of their canopy spectra, but the correlation between above ground fresh biomass and above ground dry biomass was different. The contents of chlorophyll-a, chlorophyll-b, total chlorophyll and carotenoid of leaves were all significantly correlated to their red edge position λ r, but that of the correlations to the other red edge parameters were different.