Analyzing spatiotemporal characteristics of soil salinity in arid irrigated agro-ecosystems using integrated approaches

Soil salinization is one of the most common land degradation processes that impacts agricultural production, environmental health, and economic welfare. The first task in managing soil salinity is to understand its spatiotemporal characteristics, causal factors and influences, both over large regions and within individual fields. In this study, a typical irrigated agro-ecosystem located in the upper Yellow River basin, suffering from long-term soil salinization problems, was selected as the case study area. Field sampling experiments and investigations related to soil layer salt content, groundwater, irrigation and ground elevation were carried out at three scales (field scale, canal scale and regional scale) covering both croplands and natural vegetation patches during 2016 and 2017. Spatiotemporal characteristics of soil salinity were analyzed for the three scales based on sampling data, remote sensing, geostatistical analysis and model simulation. Results showed that, at the regional scale, the soil salinity distribution was dominated by topography and groundwater depth; at the canal scale, it was dominated by irrigation and cropping pattern; at the field scale, it was dominated by micro-topography and the uniformity of field irrigation. Scale-dependent soil salinity management strategies should be adopted to maintain agricultural production and the sustainability of natural ecosystems. It can be concluded that using integrated approaches including multi scale soil sampling, model simulation and other modern techniques is an effective way for thorough understanding and management of soil salinity.