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为研究干旱区土壤盐分空间异质性,指导农业生产实践,运用大地电导率仪(EM38、EM31)对研究区域进行移动式磁感调查,获取表观电导率(ECa)。同时,通过27个校准点的采样和ECa测量,建立土壤盐分的电磁感应解译模型。干旱区土壤盐分质量分数与EM38、EM31水平模式读数(H38、H31)显示出良好的相关性(R=0.935),可以利用ECa结合GIS和地统计学知识研究土壤盐分的空间分布。采用两种方法进行研究:一种是先利用解译模型获取磁感调查点的土壤盐分质量分数,然后进行地统计分析研究其空间分布;另一种是先利用地统计分析研究H38和H31的空间分布,然后利用解译模型通过栅格运算计算盐分质量分数,精度检验显示前者预测值与实测值之间的相关性更好(R2,0.888>0.873);标准差较低(std.0.414<0.426),具有更高的预测精度。研究结果表明,基于电磁感应研究干旱区土壤盐分空间异质性是切实可行的,这对于土壤盐渍化的快速诊断,指导农业生产和促进精准农业的发展具有重要的意义。
In order to study the spatial heterogeneity of soil salinity in arid area and guide the practice of agricultural production, mobile magnetic induction investigation was conducted on the study area using the earth conductivity meter (EM38, EM31) to obtain the apparent conductivity (ECa). At the same time, through the sampling and ECa measurements of 27 calibration points, an electromagnetic induction interpretation model of soil salinity was established. The soil salinity quality scores in arid areas showed good correlation with the horizontal pattern readings (H38, H31) of EM38 and EM31 (R = 0.935), and the spatial distribution of soil salinity could be studied by using ECa combined with GIS and geostatistics. Two methods were used to study: one is to first use the interpretation model to obtain the soil salinity content of the magnetic induction point, and then carry out geostatistical analysis to study its spatial distribution; the other is to use the geostatistical analysis of H38 and H31 Spatial distribution, and then use the interpretation model to calculate the salt content by grid computing, the accuracy test shows that the former has a better correlation with the measured value (R2, 0.888> 0.873); the standard deviation is lower (std.0.414 < 0.426), with a higher prediction accuracy. The results show that it is practicable to study the spatial heterogeneity of soil salinity in arid regions based on electromagnetic induction, which is of great significance for the rapid diagnosis of soil salinization, the guidance of agricultural production and the development of precision agriculture.