Soil cations and texture are crucial in forming smooth water and salt transport channels between cultivated land and salinized wasteland

Dry drainage is typically associated with groundwater and evapotranspiration as primary mechanisms, which ignores the horizontal water flow from cultivated land to salinized wasteland. Meanwhile, soil water flow is dominated by soil pore structure. Unlike previous studies that solely assessed the salt-holding effect of salt wastelands based on soil salt content, this study integrates cationic concentration ratios, which collectively influence soil pore structure. To explore the drivers of horizontal water flow from cultivated land to salinized wasteland, we chose typical fields as the experimental site in the Yichang Irrigation Subarea of the Hetao Irrigation District, China. Ten observation points were established to measure parameters including soil water and salt cation distribution, particle size composition, clay dispersion and pore size within the 0-100 cm soil depth. The results showed that soil texture in cultivated land became coarser as proximity to the salinized wasteland increased. The subsoil layer of cultivated land exhibited the highest degree of coarseness, approximately five times greater than the surface soil layer. In cultivated soil, the 0-70 cm layer had lower water content than salinized wasteland, while the 80-100 cm soil layer in cultivated soil exhibited higher water content. The water content difference between the upper and lower depths in cultivated land gradually decreased with decreasing elevation. Cultivated soils maintained low and consistent EC1:5 values below 10 dS m(-1), whereas salinized wasteland soils (0-20 cm) peaked at > 40 dS m(-1). At the cultivated land-wasteland interface, the 10-20 cm soil layer had elevated K+/Na+ levels. Cultivated soils showed higher K+/Na+ ratios and Ca2+ concentrations exceeding Na+ levels. The highest Mg2+/Na+ ratio was at 0-50 cm near the cultivated boundary. In the soil profile at the cultivated land-wasteland interface, maximum soil suspension turbidity occurred at around 50-100 cm soil depth. Given the diversity of local environment, the soil structure variability and corresponding driving mechanisms identified in this study may not universally apply, and it's crucial to explore region-specific mechanisms.