Analysis of spatial-temporal variation of the saline-sodic soil in the west of Jilin Province from 1989 to 2019 and influencing factors

• Soil salinization in the west of Jilin province for a long term was monitored. • Meteorological conditions are the most relevant and important factors in soil salinization. • The implementation of government policies reversed the saline soil expansion. • Salinized soil was mainly converted to grassland and cropland. Soil salinization is a serious land degradation phenomenon that significantly affects regional economies and agricultural development. Since the 1980s, the state of soil salinization has been constantly changing due to various climatic conditions, human activities, and the application of soil improvement measures. In this study, the Landsat-5 TM and Landsat-8 OLI satellites, launched in 1984 and 2013, respectively, were used to track changes in soil electrical conductivity (EC), a key indicator of soil salinity. A remote-sensing inversion model for the EC of saline-sodic soil was established (R = 0.5), and the soil EC in western Jilin Province from 1989 to 2019 was inverted. Then, the temporal and spatial variation characteristics of the soil salinization degree were counted, and the related variables and influencing factors were analyzed. The results are in good agreement with the conclusion that meteorological conditions are the most relevant and important factors in soil salinization. The area of saline soil increased continuously in the natural state (from 1989 to 1999), and the implementation of government policies (1999 to 2019) reversed the saline soil expansion, converting large areas of saline soil to grassland and cropland. This study is the first to quantitatively analyze the degree of soil salinization and its influencing factors in western Jilin Province from 1989 to 2019; this work also successfully predicted and monitored the variation in soil salinization. This provides data support for the study of the dominant elements in soil salinization changes and the rational development of land.