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通过辽宁锦州地区春玉米不同生育时期的土壤水分控制试验,利用ASD Field Spec Pro FR分光辐射计观测不同生长状况的玉米冠层高光谱反射率,分析光谱反射率变化特征,建立光谱参数对土壤水分的反演模型。结果表明:玉米在七叶-拔节期受到干旱胁迫后,750~1400 nm波段冠层光谱反射率、红边幅值、红边面积均出现降低,350~750、1400~2300 nm反射率出现升高趋势;750~1400 nm、红边幅值、红边面积对土壤干旱胁迫的响应时间较短,且存在异于正常灌溉处理的光谱特征;反演方法中,逐步回归方法利用高光谱反射率反演土壤含水量的误差小于一阶导数光谱,反演10 cm土壤含水量的效果好于30 cm。
Through the soil moisture control experiment of spring maize at different growth stages in Jinzhou, Liaoning Province, the hyperspectral reflectance of corn canopy was measured by ASD Field Spec Pro FR spectrophotometer. The change of spectral reflectance was analyzed, and the spectral parameters of soil moisture Inversion model. The results showed that the canopy spectral reflectance, red edge amplitude and red edge area of 750 ~ 1400 nm band of corn declined after drought stress in the seven-leaf stage and jointing stage, and the reflectance of 350-750 and 1400 ~ 2300 nm appeared rising The response time of 750 ~ 1400 nm, red edge amplitude and red edge area to soil drought stress was short, and the spectral characteristics were different from those of normal irrigation. In the inversion method, the stepwise regression method used the hyperspectral reflectance The error in inverting the soil water content is less than the first derivative spectrum, and the effect of 10 cm soil moisture inversion is better than 30 cm.