吐鲁番盆地葡萄园土壤重金属铅含量高光谱估算

Hyperspectral Estimation of Heavy Metal Pb Concentration in Vineyard Soil in Turpan Basin

土壤重金属铅污染作为现代工矿业发展的产物,已逐渐入侵到农业生产和农产品中。高光谱技术由于具有宏观、快速、高效的特点已成为土壤重金属监测的重要手段。以新疆吐鲁番盆地葡萄园土壤Pb元素为研究对象,分析土壤原始光谱在内的15种光谱变换下的土壤光谱反射率数据与土壤Pb含量的关系,构建土壤Pb含量偏最小二乘回归(PLSR)模型和地理加权重回归(GWR)模型,对比分析并探讨运用土壤高光谱估算葡萄园土壤Pb含量的可行性。结果表明:土壤原始光谱反射率通过光谱变换能有效增强葡萄园土壤Pb元素的光谱特征及模型估算精度,其中,平方根二阶微分(SRSD)变换的PLSR模型和GWR模型估算能力最优。采用GWR模型比PLSR模型更好的解释葡萄园土壤重金属Pb含量高光谱估算。从模型稳定性和精确性来看,在平方根二阶微分变换中GWR模型R^(2)从PLSR模型的0.262提高至0.866,平方根误差减少了1.009。采用GWR模型可有效提高估算葡萄园土壤Pb含量的精度,为中国葡萄园基地土壤重金属污染以及土壤环境安全研究提供有益借鉴。

As a product of the development of modern industry and mining,soil heavy metal lead pollution has gradually invaded agricultural production and agricultural products.Hyperspectral technology has become an important method for monitoring heavy metals in soil due to its macroscopic,rapid and efficient characteristics.This study takes the Pb element of vineyard soil in Xinjiang Turpan Basin as the research object,analyzes the relationship between soil spectral reflectance data and soil Pb content under 15 spectral transformations including the original soil spectrum,and constructs a partial least square regression of soil Pb content(PLSR)model and geographic weighted re-regression(GWR)model,comparative analysis and discussion of the feasibility of using soil hyperspectral to estimate the vineyard soil Pb content.The results show that the original spectral reflectance of the soil can effectively enhance the spectral characteristics of the vineyard soil Pb element and the estimation accuracy of the model through spectral transformation.Among them,the SRSD transformation PLSR model and GWR model have the best estimation capabilities.The GWR model is better than the PLSR model to explain the hyperspectral estimation of the heavy metal Pb content in vineyard soil.From the perspective of model stability and accuracy,in the SRSD differential transformation,the GWR model R^(2) is increased from 0.262 of the PLSR model to 0.866,and the RMSE is reduced by 1.009.Using GWR model can effectively improve the accuracy of estimating the Pb content of vineyard soil.This study provides a useful reference for the study of soil heavy metal pollution and soil environmental safety in Chinese vineyard bases.