Title: Climate warming and intensive agricultural activity coupling alleviates surface accumulation of soil salinity in the whole-profile of cultivated land in North China
Abstract: Soil salinisation under global climate warming has become a critical challenge worldwide. Intensive agricultural activities contribute to the uncertainty of soil salinity distribution. This study focused on cultivated land in North China, where 519 whole-profile soil samples (0-120 cm, collected at 20 cm intervals) were systematically collected and analysed. Based on these data, an integrated assessment framework was developed to accurately determine the spatial distribution patterns of whole-profile soil salinity. Furthermore, the effects of climate, topography, soil properties and cultivation practices on soil salinity were explored, with the response mechanism of whole-profile soil salinity in cultivated land to the coupled effects of climate warming and intensive agricultural activities being quantitatively revealed. The results indicated the following. (1) The spatial distribution of whole-profile soil salinity followed a northwest-low to southeast-high pattern. Based on vertical differentiation characteristics, four types of salinity distribution profiles were identified: surface aggregation profile (SAP), bottom aggregation profile (BAP), uniform distribution profile (UDP) and vibration distribution profile (VDP), with UDP (36.14 %) and BAP (33.04 %) predominating. (2) The ratio of evaporation to precipitation, elevation, slope, soil texture, soil pH and cultivation practices significantly affected whole-profile soil salinity, while cultivation practices primarily influenced salinity distribution in the 0-40 cm soil layer. (3) The structural equation model (SEM) results indicated that climate (Direct Path Coefficient, DPC = 0.19 to 0.36) and soil properties (DPC = 0.39 to 0.65) positively affected soil salinity, whereas topography (DPC = − 0.54 to − 0.69) had a negative effect. The influence of cultivation factors on soil salinity shifted from a negative effect to a positive effect at a depth of 40 cm (DPC = − 0.23 to 0.14). Overall, intensive agricultural activities did not lead to surface soil salinity accumulation. Instead, irrigation counteracted the salinity accumulation effect that was intensified by climate warming, effectively reducing surface soil salinity in the cultivated land profile. This study underscores the importance of a whole-profile perspective in managing soil salinity under the combined influence of climate warming and intensive agricultural activities. The findings provide valuable data support for mitigating soil salinisation in major grain-producing regions.
Keywords: Soil salinity ;Whole-profile; Cultivated land; Response mechanism; Structural equation model (SEM)
DOI: https://doi.org/10.1016/j.jenvman.2025.127811
