Investigation of EM38 accurassy for monitoring of soil salinity and its comparing with traditional method (Case study: Yazd-Ardakan plain)

Extent of soil salinity in vast areas of the country، verifies the necessity of advanced techniques and tools for monitoring of salinity at different scales farm، field، catchment and national scales. Electromagnetic induction (EM) is a technique that can be used for mapping of soil salinity in bareor cultivated land condition with no extensive field works and large soil samples. The main objective of this study is to evaluate the ability of EM38 device for soil salinity mapping of 5،000 hectares of the Yazd-Ardakan plain soils. For this purpose، soil samples were collected from descrete depths (0-15، 15-30، 30-60 and 60-100 cm) as well as vertical and horizontal readings of EM38in sampled locations. Electrical conductivities of soil saturated pastes (ECe) were measured in the laboratory and then، relationships between EM38 readings and ECe were analyzed. Results showed that the EM38 instrument can be recommended as a rapid، accurate (R2>0. 75)، and RMSE=0. 41) and relatively low cost technique for in-situ measurement of soil salinity. However، soil moisture should be considered as a major limitation for this technique.