水稻、玉米、棉花的高光譜及其紅邊特徵比較

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(subscript r) and red edge area S(subscript r) of the canopy spectra for three crops, but the change extents and rules for their red edge position λ(subscript r) were different. The leaf area indices and fresh leaf mass were very significantly correlated to the red edge parameters λ(subscript r), Dλ(subscript r) and S(subscript 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(subscript r), but that of the correlations to the other red edge parameters were different.