The Effect of Gravel Mulch on soil Evaporation and Resistance: Experimental Findings and Modeling

Gravel mulch has emerged as a highly effective strategy for reducing evaporation in arid region. However, the accuracy of models in simulating evaporation under mulch conditions and the mechanisms by which mulch influences evaporation resistance remain poorly understood. This study aimed to investigate the effects of gravel mulch on the evaporation processes and evaporation resistance across different soil textures.

Soil evaporation was observed in a column experiment using various mulch proportions (T1(0), T2, (25 ± 6%), T3(50 ± 4%), T4 (75 ± 4%), and T5 (97 ± 3%)). And the Hydrus-1D model was used to simulate the evaporation process, obtain the surface soil water content.

The findings indicated that soils covered with gravel exhibited significantly lower evaporation rates compared to bare soil, with the effect being particularly pronounced in finer-textured soils. The evaporation coefficient ‘a’ decreased with increasing gravel mulch proportion, demonstrating the mulch’s effectiveness. The Hydrus-1D model had a good performance in simulating water transport and cumulative evaporation flux under these conditions (R² > 0.7). While gravel mulch increased total evaporation resistance, it reduced soil surface resistance, with mulch resistance being the primary contributor to the overall increase in evaporation resistance.

Gravel mulch had a greater impact on finer-textured soils, suggesting a need for texture-specific application strategies for managing gravel mulch effectively. This study confirms the performance of gravel mulch in reducing evaporation, with important implications for agriculture and water conservation practices in arid region.