Abstract: In this paper, the relationship between the EM38 earth conductivity measurement and soil (1:5) conductivity solution was analyzed, and the prediction models were developed by taking soil solution conductivity as a dependent variable and earth conductivity as an independent variable. In order to ensure the credibility of the models, the credibility of EM data was analyzed. Through correlation analysis between EM_h and EM_v, the results revealed that the standard mode was consistent with the EM measurement in vertical mode and was capable of reflecting soil salt content, so the data were applicable. An ideal prediction model should be selected in predicting soil salt content. The values of EM38 measurement of earth conductivity could be used to predict soil salt content and analyze the spatial variation of soil salinity. Results showed that the spatial variation of soil salinity in the study area was the salt accumulation in topsoil and zonal. Results showed that the angle of salt zone between the shallow soil layer (0-30 cm) and the moderate (30-60 cm), deep (60-90 cm) and bottom (90-120 cm) soil layers was larger than 5°, but within 3° between it and other soil layers. Especially, the zonal trend of soil salt content in shallow soil layer was consistent with that of vegetation and fitted the change features of landforms in the study area.

Key words: EM38, soil salinity, conductivity, zonality, spatial variability