Assessing Spatio-temporal Variations in Land Use/Land Cover and Soil Salinity and their Impact on Managing Dry Areas (Case Study: A Part of Sistan Basin, Southeast of Iran)

The negative effects of soil salinity on natural and human environments have turned such phenomenon into one of the serious threats to the sustainable management of arid and semi-arid areas. The present study aims to evaluate the spatial-temporal variations in land use/land cover and soil salinity in a part of Sistan basin located in the arid regions of southeastern Iran, which has been exposed to the phenomenon of soil salinity during the recent years. To this aim, land use/land cover and soil salinity maps were prepared for 1989 and 2019 using the measurements obtained from ground sampling and instruments such as remote sensing (RS) and geographic information system (GIS). Based on the results, the normalized average soil salinity was 0.322 during 1989, reaching 0.52 during 2019 with a growth of 0.188. In addition, comparing the trend of salinity increase and land use/land cover variations in the region indicates that such factors affect each other significantly. Further, the conversion of land use/land cover from irrigated agricultural uses and water bodies to bare lands, rainfed agriculture, and man-made areas has decreased the vegetation cover and water areas, leading to an increase in soil salinity due to the erosion created by the 120- day wind of Sistan and sedimentation of salt particles in the whole region. Chah-nimehs have not been able to fully compensate for the adverse effects generated by the destruction of habitats and drying up of a part of Hamun Lake and Hirmand River, despite their slight success in reducing the environmental obstacles.