Modeling root zone soil moisture dynamics under the influence of shallow groundwater table by considering capillary rise

Moisture uptake by crops from shallow groundwater tables (SGT) plays a crucial role in modeling field-level hydrological processes. Capillary rise from the SGT is a key factor in soil-water-plant interactions. A non-linear root uptake numerical model has been developed to simulate soil moisture variation in the crop root zone (CRZ). The model uses an empirical capillary rise model as the upward flux at the lower boundary of the soil profile to assess the influence of SGT on soil moisture dynamics. Field data from Lysimeter experiments on Wheat, Pea, and Maize were used to evaluate the model’s performance in predicting moisture uptake. The model showed good agreement with experimental results, simulating soil moisture profiles and moisture status at different depths in the CRZ. The performance indicators, including R2 (0.66–0.84), NSE (0.68–0.85), and MBE (0.04 to −0.05), remained within acceptable limits, demonstrating the model’s reliability. Simulations incorporating capillary rise aligned well with observed data, while predictions without capillary rise showed poor agreement. The results demonstrate the effectiveness of this model in predicting moisture uptake in CRZ with an SGT, providing a valuable tool for optimizing surface irrigation and enhancing crop yield.