通过水稻冠层光谱变化特征可直接或者间接反映耕地重金属污染状况。研究在光谱分析的基础上,采用植被指数(包括NDVI、DVI、SR、VOG、mSR705、SIPI)和相关分析相结合的方法提取与土壤中Cd、Pb、Zn相关的水稻冠层光谱敏感参数,通过最小二乘拟合建立土壤重金属全量反演模型。结果显示Cd、Pb与大部分植被指数存在显著负相关,基于NDVI(R1000,R670)的二次拟合模型能够有效地预测Cd全量,Pb估算模型以基于DVI(R1030-R670)的线性模型为最佳,表明重金属污染下的水稻冠层光谱变化特征能够获取土壤重金属含量信息,可监测耕地土壤重金属污染状况。
Spectral characteristics of rice canopy can directly or indirectly reflect the status of heavy metal pollution in farmland.On the basis of spectral analysis,this study combined the vegetation index (NDVI,DVI,SR,VOG,mSR705,SIPI) with correlation analysis to extract the spectral sensitivity parameters of rice canopy of Cd,Pb andZn in the soil,and then established the soil heavy metal total quantitative inversion model by the least squares fitting.Results showed that Cd,Pb and most of the spectral parameters are significantly negative correlation.The quadratic fitting model based on NDVI(R1000,R670) can effectively predict the Cd content,and the linear model based on DVI(R1030-R670)can effectively predicted the Pb content.