Spatial heterogeneity of soil salinity in typical arid area based on electromagnetic induction

To research the spatial heterogeneity of soil salinity in arid areas for guiding the agriculture production, mobile electromagnetic induction (EM) survey with EM38 and EM31 was performed to measure apparent soil electrical conductivity (ECa). 27 calibration sites samples were selected for ECa measurements at the same time, then the EM interpretation model on soil salinity was established. The experimental results showed a good correlation between the soil salinity and the ECa data of H38 and H31 which were respectively measured by EM38 and EM31 in horizontal mode in the arid area (R=0.935). The soil salinity spatial distribution can be studied by ECa data combined with GIS and geo-statistics techniques. Two ways were introduced for research in the paper: one was that the soil salinity on EM survey sites was interpreted by the interpretation model, then the spatial distribution was studied by geo-statistics technique; the other was that the spatial distribution maps of H38 and H31 were studied by geo-statistics technique, then the soil salinity was calculated with the interpretation model by rater calculator. The precision test showed the former way had better accuracy, which the correlation between the measured values and the predicted values was better (R2: 0.888>0.873), and the standard error was less than the latter (0.414<0.426). The results indicate that the research on spatial heterogeneity of soil salinity with electromagnetic induction (EM) in arid areas is reliable, and has important significance for rapid survey on soil salinization, guidance of agriculture production and development of precise agriculture.