Simulation of Soil Moisture Dynamics Using Root Water Uptake Models under Stage-Specific Stress Conditions

Accurate representation of root water uptake processes is critical for simulating soil water dynamics under crop water stress, particularly when stress coincides with variable rainfall events. HYDRUS provide a useful framework for evaluating plant–soil interactions under contrasting moisture conditions by simulating different modes of root water uptake, such as compensated and non-compensated uptake.

An experimental study was conducted to examine soil–plant water dynamics under water stress occurring at different crop growth stages. The study focused on three distinct stress scenarios: (a) no water stress, (b) water stress during the vegetative phase, and (c) water stress during the flowering stage. Field measurements included soil water potential at 10 cm depth and root traits, specifically root length and root biomass, to characterize plant water availability and rooting behavior under contrasting moisture conditions.

The HYDRUS-1D model was applied to simulate soil water content dynamics using both compensated and non-compensated root water uptake formulations. Root length and biomass data were used to define root distribution functions in the model. Simulated soil water potential patterns were compared qualitatively across growth stages and root water uptake approaches. The results indicated that the compensated root water uptake model better represented soil moisture depletion and redistribution patterns under stress conditions, particularly when rainfall events occurred during flowering and grain filling stages. Overall, the study highlights the importance of incorporating compensation mechanisms in root water uptake models to improve the simulation of soil water dynamics under stage-specific crop water stress.