Abstract:Aiming at the problem of soil salinization in salinized irrigation areas,taking Wulate Irrigation Area in the lower reaches of the Hetao Irrigation District, Inner Mongolia as the research area,through the combination of field test and indoor test analysis, the redundancy analysis method was used to explore the correlation between salt segregation elements and total salt, pH value, and nutrients in the root layer soil (0~20cm, 20~40cm) in spring and autumn on the salinized improved cultivated land and wasteland,and its change characteristics and quantitative relationship were clarified, and the salt migration of 1m soil between the improved cultivated land and the wasteland in the experimental area was estimated. The results showed that the anions of the improved farmland and wasteland soil were mainly Cl-, accounting for 45.27% and 58.78% of the total anions, respectively, and the cations were mainly Na+, accounting for 60.67% and 53.94% of the total cations respectively. The total salt content of wasteland exceeded 7.0g/kg on average, and the degree of soil salinization was relatively serious. Redundancy analysis showed that SO2-4, Cl- and Ca2+ played the leading role in improving the total salt content of cultivated soil, and Cl-, Mg2+ and Na+ played the leading role in the total salt content of wasteland soil. The change of soil pH value was mainly related to HCO-3. Improved cultivated land had a significant negative correlation between available phosphorus and Na+ (P<0.05), wasteland available potassium had a significant positive correlation with K+ (P<0.05), and available phosphorus had a significant negative correlation with Na+ (P<0.05). In the first two ranking axes, the cumulative proportion of changes in the relationship between the cultivated land research object and the environment was 71.38% and 71.65%, respectively. The cumulative proportions of changes in the relationship between wasteland research objects and the environment were 89.02% and 89.16%, respectively, reflecting the linear relationship between the research objects and environmental variables of the improved cultivated land and wasteland. In cultivated land, Na+ had the most important impact on total salt, pH value, and soil nutrients, followed by Ca2+;in wasteland, Na+ had the most important impact on total salt, pH value, and soil nutrients, followed by K+. In one growth cycle of crops, the amount of salt accumulated in 1m of wasteland soil was 939.842kg/hm2. Groundwater replenishment brought salt into the soil, accounting for 70.06% of the salt accumulation. The salt transferred from the cultivated land groundwater to the wasteland during the irrigation period was concentrated in the 60~100cm soil and accounted for 22.83% of the salt accumulation. The amount of salt that the cultivated land penetrated into the wasteland was 7.11% of the salt accumulation.