Sustainable Irrigation and Fertilization Strategies for Maize in Arid Regions: Insights from Numerical Modeling and Simulation

Climate change and increasing socio-economic pres-sures are intensifying the demand on water resources, particu-larly in arid and semi-arid regions like Burkina Faso. Effective water and fertilizer management are crucial to sustain agri-cultural productivity while minimizing environmental impacts. This study employs HYDRUS 2D to model the coupled transport of water, solutes, and heat in a sandy-textured soil under drip irrigation for maize cultivation. Four irrigation scenarios were evaluated with respect to the crop evapotranspiration (ETc, mm/day): 50% ETc, 75% ETc, 100% ETc, and 150% ETc, reflecting deficit, normal, and excessive water supply conditions. Results show that deficit irrigation treatments (50% ETc and 75% ETc) with daily water application significantly reduce nitrogen losses from fertilizers (NPK and urea) beyond the soil column. This is attributed to a reduced wetting front, which limits nitrogen leaching and enhances nitrogen retention within the root density zone, thus improving nutrient availability for plants. For fully irrigated (100% ETc) and excess (150% ETc) scenarios, substantial water and nitrogen losses were observed, with over half of the inputs leached beyond the soil profile. To mitigate these losses, optimized irrigation schedules were proposed: 72-hour intervals during the initial growth phase and 48-hour intervals during the remaining growth stages for 100% ETc, and 72-hour intervals during the first three growth stages followed by 48 hours in the late-harvest phase for 150% ETc. Overall, the study highlights that deficit irrigation strategies not only conserve water but also maintain adequate nitrogen levels within the root zone, offering a sustainable approach to resource management in water-limited environments.