Ecohydrological benefits of soil mulching across rainfall regimes

Soil mulching is a cropland management practice that provides several benefits for the soil and the plant, especially in rainfed systems. Soil mulching tends to enhance plant growth by reducing soil evaporation and potentially increasing transpiration, but its effectiveness varies widely across climate conditions, especially rainfall regimes and mulching materials. Our goal is to investigate how soil mulching can be managed across different rainfall regimes to enhance crop health and yield and how it can be used to limit the impact of climate changes. We use a process-based model to link the dynamics of soil and mulching moisture to crop growth and apply it to field observations for different mulching materials. We then analyze the soil mulching effectiveness under different rainfall regimes and mulching layer thicknesses. For most rainfall scenarios, the mulching reduces soil evaporation and increases plant transpiration. However, particularly for climates characterized by rainfall with low frequency but high intensity, soil mulching might contribute negatively to plant transpiration, especially for a mulching layer thickness smaller than 5 cm. We also show that soil mulching is particularly beneficial during a dry spell, a phenomenon that is projected to occur more frequently in many climatic zones. The analysis helps better understand the role of soil mulching on transpiration and crop growth and provides important information for improving soil mulching management depending on the site-specific rainfall regime and available mulching material.