为揭示中原黄泛区土壤盐分三维空间分布特点,以河南省封丘县为研究区域,综合应用土壤采样数据与遥感影像数据,利用光谱指数法与三维反距离权重法(IDW)对三维土壤盐分空间变异特征进行了解析与评价,显著提升了区域土壤盐分的三维预测精度。研究区域土壤电导率变异系数在0.218-0.324之间,属中等变异强度;各层土壤电导率的平均值在0.121-0.154ds·m-1之间,土壤盐分高值区主要分布在天然渠与黄河沿线区域,研究区盐渍土剖面类型属“底聚型”,即随着深度增加土壤盐分含量逐渐增大,呈现底土积盐的趋势;该研究表明应用以光谱指数数据为基础的三维IDW方法对区域土壤盐分三维特征进行解析可以达到较高精度。该研究为中原黄泛区盐渍障碍耕地的治理利用提供了可靠技术方法。
In order to illustrate the three-dimension spatial variability of soil salinity in central China flood area of the Yellow riv- er, integrated soil sampling data and remote sensing data, spectral indices and inverse distance weighting (IDW) method were applied to the estimation and simulation of three-dimension spatial distribution of soil salinity. The study was carried out in typi- cal central China flood area of the Yellow river in Fengqiu County, Henan Province, China. The electrical conductivity of the saturation extract (EC1. s ) of 505 soil samples collected at 101 points was measured. The results indicated that the coefficient of variation of soil salinity at each soil layer is from 0. 218 to 0. 324 and exhibited the moderate spatial variability. The average of soil electrical conductivity is from 0. 121 to 0. 154 ds . m-1. The 2 820 three-dimension spatial scattered data for soil electrical conductivity were taken at soil salinity mapping interpreted by spectral indices and soil electrical conductivity. Three-dimension IDW interpolation showed that a large area of high soil salinity mainly located in the region of Tianran canal and the along of the Yellow river. The shape of the soil salinity profile was downward flowed, revealing soil salinity increasing with depth in whole soil profile and soil salinity accumulated in the subsoil. The accuracy of the predictions was tested using 20 soil sampled points. The root mean square error (RMSE) of calibration for three-dimension distribution of soil salinity showed that the IDW method based on spectral indices was ideal. The research results can provide theoretical foundations to the management and utilization of salt-affected land in China flood area, especially in the Yellow river zone.