Spatiotemporal Dynamics of Soil Salinity and Its Determinants in Songnen Plain

Abstract

【Objective】 Soil salinization is a dynamic process, affected by numerous factors. Understanding its spatiotemporal variation in a region and catchment is important for management. In this paper, we present the soil salinity dynamics and its determinants in Songnen Plain of Heilongjiang province. 【Method】 The calculation was based on remote sensing imagery of the region acquired from 2000—2020. We used correlation analysis and relative contribution rate analysis to map the spatiotemporal distribution of soil salinity in this region. 【Result】 On average, areas affected by salt in the region had decreased from 2000 to 2020, at a rate of 2.73 km2/a. But this is mainly due to the reduced soil salinization in some regions, as other regions actually had seen an increase in soil salinization. In particular, soil salinization in Qiqihar had increased because of the increase in cropped lands and GDP. Suihua also saw soil salinity rising due to increased plant areas and population. In contrast, soil salinity in Daqing and Harbin had decreased, due to the increase in surface water resources and decrease in evaporation for Daqing, and the change in cropped land and livestock industry for Harbin. 【Conclusion】 Change in soil salinization from 2000 to 2020 in Songnen Plain varied, with some areas seeing an increase and others witnessing a decline. In addition to climate change, other reasons underlying such variations in soil salinization include economic development, change in cropping systems and livestock industry. To ameliorate soil salinization and improve land quality, this region should consider improving irrigation and drainage facilities and controlling the groundwater depth not exceeding a critical level.

Keywords

• land salinization
• space-time change
• remote sensing interpretation
• songnen plain
• influence factors