Roadmap on tools and simulation models for agroforestry microclimate and water status. DigitAF EU project. Deliverable 2.8

The presence of trees in agroforestry systems has a substantial effect on the crop’s microclimate (Jacobs et al., 2022). Specifically, trees reduce the wind speed, the light availability and the crop temperature, and increase the relative humidity, all of which tend to reduce crop evapotranspiration (ET), which is the sum of soil evaporation and plant transpiration. Because of this, the crop water demand tends to be lower in agroforestry systems. However trees also compete with the crop for water. Trees intercept rainfall and only a fraction of precipitation reaches the ground below canopies. They also uptake large amount of water from the soil to ensure their transpiration, reducing the amount of water available for crops. The crop’s water status therefore depends on the balance between the reduced demand and the reduced availability of water. This balance is impacted by a large number of interacting factors, including tree and crop root architecture, soil depth and hydraulic properties, trees canopy structure, tree and crop phenology and climatic conditions. Because of this complexity, process-based models, taking into account many of these factors, are useful tools for improving our understanding and for optimizing agroforestry designs. 

In this roadmap we will first briefly review the current status of microclimate and water status
modelling in agroforestry systems, thereby identifying the knowledge gaps. Then, we describe the activities within DigitAF to address these knowledge gaps, as well as ongoing initiatives outside the project. Finally, we highlight future directions towards a better representation the crop and tree water status in agroforestry systems.