【Objective】The mulched sand field system in arid and semi-arid regions of Northwest China has long been used for crop cultivation, where a surface gravel layer plays a critical role in moisture conservation and soil protection. However, over continuous cultivation periods exceeding 30 years, the degradation of these sand fields has become increasingly evident, yet the weathering behavior of the gravel cover under water-rock interaction and its potential contribution to soil nutrient replenishment remain poorly understood.【Method】To address this knowledge gap, this study selected a degraded sand field that had been under continuous cultivation for more than 30 years and was currently in a fallow phase. Gravel samples within the major particle size ranges present in the field were collected and analyzed to investigate their physical and chemical weathering responses to repeated dry-wet cycles. Furthermore, the study sought to reveal the regulatory mechanisms by which element leaching from the weathered gravel influences the nutrient status of the underlying plough layer soil.【Result】The results of this investigation are summarized as follows. (1) The gravel used for mulching in the studied sand field is predominantly composed of silicate minerals, which possess a certain intrinsic weathering potential and a notable capacity for nutrient release. Under the influence of dry-wet cycling, the slightly alkaline water environment in the field imposed only a limited chemical weathering effect on the gravel, whereas physical weathering played a dominant role. The water-rock interaction significantly accelerated gravel mass loss and enhanced the gravel’s water absorption efficiency, with all observed differences being statistically significant (P < 0.05). Among the different particle size fractions examined, the fine-grained gravel with a size range of 5 to 10 mm exhibited the most sensitive response to the imposed dry-wet cycles. This fraction achieved the highest mass loss rate, recorded at 2.09%, and the highest water absorption rate, reaching 1.70%. Compared with the control group (no dry-wet cycles or water-rock interaction), these values represent substantial increases of 242.11% and 23.10%, respectively. (2) No significant transformation or conversion among secondary minerals was detected throughout the experimental period. However, chlorite showed the most pronounced loss in the fine-grained gravel fraction, decreasing by 10% due to the combined effects of thermal stress induced by temperature fluctuations and the leaching action of infiltrating water. Accompanying the loss of pore-filling, magnesium-rich chlorite, various elements in the plough layer soil exhibited different degrees of enrichment. The sequence of element release from the gravel into the soil, ranked from highest to lowest relative release intensity, was ranked by ability as follows: Mg > Ca > Fe > Mn > K > Zn. (3) Correlation analyses and principal component analysis (PCA) further confirmed that the physical weathering characteristics of the gravel, including mass loss and water absorption rate, were significantly correlated with the content of rock-forming elements in the soil (P < 0.05). This finding demonstrates that water-rock interaction under dry-wet cycles has a pronounced influence on gravel fragmentation and also significantly modulates the elemental composition of the soil.【Conclusion】In conclusion, the dry-wet cycling process serves as an effective accelerator for the weathering of mulching gravel in degraded sand fields. The elemental leaching accompanying gravel fragmentation plays an important role in supplementing soil nutrients in the plough layer. Notably, the fine-grained gravel fraction exhibits the strongest nutrient release capacity among all tested particle sizes. These results suggest that the surface gravel layer in degraded sand fields possesses a certain potential for resource utilization in terms of nutrient supply. This study provides a new and valuable perspective for improving the soil environment of mulched sand fields, mitigating the ongoing degradation of such fields, and facilitating their future reclamation.