Soil salinization mapping across different sandy land-cover types in the Shiyang River Basin: A remote sensing and multiple linear regression approach

Abstract

Soil salinization has a critical impact on land in arid and semi-arid regions. Consequently, mapping and monitoring saline soils have been the subject of growing attention for many scientists due to the irregular spectral reflectivity related to geographic locations and landscape characteristics, which are challenging for policy-makers to improve and sustain the ecological balance. This study applied geoinformation techniques combined with multiple linear regression modeling to map soil salinity over different land-cover types in the Shiyang River Basin. Based on field knowledge and area accessibility, eighty samples were collected, then Kennard-Stone (K–S) algorithm was used for sample partition, 70% for training, and 30% for validation. Variance Inflation Factor (VIF) was applied to identify multicollinearity and adjust the model covariates to ensure proper specification and functioning. Mobile sand, water channels, built-up, and mountainous areas were masked. The results revealed the model's high performance with a coefficient of determination R2 of 0.898, a probability level of 95%, a Root Mean Square Error (RMSE) of 1.653, a Ratio of the Performance to the Interquartile range (RPIQ) of 4.182, and standard error of Electric conductivity (EC) laboratory measurements to the standard error of the predicted EC (SE Lab/SE Pred) of 1.048. Overall, an area of 13834.59 km2, accounting for 33.54% of the entire study region, is under salinization threat. The basin's lower reach is the most affected, with 9576.25 km2, accounting for 57.64% of the eco-region, and 4258.34 km2, around 32.12% of land in the middle reach, suffering from soil salinization. 80.46% of farmland in the lower reach and 35.99% in the middle reach are saline soils. Around 98.9% of Gobi in the lower reach and 91.55% in the middle reach suffer from soil salinization, 96.62% of rangeland in the lower reach and 44.62% in the middle are under salinization risk. Generally, the highest salinity values were recorded in the intermontane basins, followed by the Gobi regions, rangeland, a significant part of cropland in the lower reach, and a small part of cropland in the middle reach. This research establishes a scientific foundation for soil salinization scenarios monitoring under arid climates; hence the outcome results are crucial for complementary landscape planning, ecological restoration projects, and water resources allocation in the Shiyang River Basin.