露天煤矿排土场地表的光谱特征和土壤参数分析

Characteristics of Soil Spectral Reflectance and Estimation of Soil Parameters in Fuxin Opencast Coal Mine

以辽宁海州煤矿露天排土场为研究对象,分析了地表土壤光谱特征以及反射光谱与地表土壤参数的相关性。土壤反射光谱分析结果表明:不同排土年限光谱反射率随排土年限的增长而降低;不同土质中灰土和混合土的水分吸收谷表征不明显,红壤土、黄土和红砂土光谱反射率以红壤土为最高,以下依次为黄土和红砂土。土壤反射光谱与土壤参数相关性分析结果表明:有机质含量与反射光谱相关性最高处的相关系数为-0.76,其他参数与反射光谱相关系数较低。建立土壤有机质含量预测模型(建模R2C=0.7374,模型检验R2V=0.6824)满足检测要求。分析了1910和1943nm处光谱反射率与土壤含水量之间的关系,结果表明由于排土场土壤的多样性和复杂性,土壤全样本光谱反射率与土壤含水量之间呈非线性相关,分别依年代、土质分组后,土壤光谱反射率与土壤含水量均呈线性相关。

The surface soil samples of Fuxin opencast coal overburden dumps were collected in the field and the spectral reflectance and characteristic parameters of the soil samples,such as moisture content,pH,electrical conductivity（EC）,available potassium（K＋）content,and soil organic matter content（SOM）,were measured.The Analysis results indicated that the curves of the soil spectral reflectance decreased with increasing the laid years.The possible reasons were the influences of soil texture and color.Although the valleys of the spectral reflectance appeared at 1 420,1 910 and 2 210 nm,they were not conspicuous on the lime soil and mixture soil reflectance curves at 1 420 and 2 210 nm.With discussing the spectral reflectance of different types of soil texture,it＇s easy to find that the reflectance of fine grained soil was higher than the rough grained soil.Correlations between soil spectral reflectance and soil parameters were analyzed.The results showed that there was a positive relation between reflectance and pH,and correlation coefficient decreased with the wavelength increasing There was no relationship between spectral reflectance and EC,and negative relations were observed between spectral reflectance and soil parameters,K＋ and SOM,respectively.A high correlation coefficient was found between spectral reflectance and SOM,and the highest correlation coefficient reached-0.76.The exponential correlation was found between sol spectral reflectance and soil moisture content to analyze all samples.According to different years and textures,more detail was described about the correlation between spectral reflectance of characteristic wavelength（1 910 and 1 943 nm）and soil moisture content.Meanwhile,the linear correlations were found under different conditions and higher correlation coefficients were obtained.In order to estimate SOM,five wavelengths（1 350,1 602,1 862,2 160 and 2 227 nm）were selected based on principal component analysis to build a multiple linear regression model.The multiple correlation coefficient of calibration model（R2C）was 0.737 4,and the multiple correlation coefficient of validation（R2V）was 0.682 4.It indicated that the model was able to meet the needs of monitoring SOM in Fuxin opencast coal mine.