The Tree-Crop Interface: Soil Moisture Relations

Understanding the soil moisture dynamics and evapotranspiration (ET) patterns in the tree-crop interface is crucial for effective design and management of agroforestry systems, particularly in water-limited environments. In this chapter, we conducted a comprehensive analysis of soil moisture conditions, ET, and their key influencing factors in agroforestry. Subsequently, we developed an integrated ET and soil water balance model to unravel the underlying mechanisms governing soil moisture dynamics. Furthermore, we investigated the soil moisture conditions and ET relationships in an apple tree-cocksfoot agroforestry system established in the Loess Plateau of China. Our findings indicate that the ET and soil water balance coupling model successfully captured the intricate water cycling processes within agroforestry systems. This model holds promise for evaluating water utilization efficiency and informing the design and management of agroforestry systems across diverse environmental contexts. We emphasize the significance of appropriate field management practices, such as maintaining low coverage of understorey crop species, to mitigate the potential negative impacts of interspecific competition on tree performance in agroforestry under water-limited environments. We encourage the adoption of agroforestry systems incorporating well-managed understorey crops to enhance water productivity while providing valuable ecological services.