Effect of irrigation regimes on nutrient uptake and nitrate leaching in maize (Zea mays L.) production at Birr-Farm, Upper Blue Nile, Ethiopia

Sustainably managed irrigation water is essential to agriculture. In order to identify the best irrigation strategies for maximizing agricultural productivity and environmental health, this study examines the effects of various irrigation depths on nutrient uptake, nitrate leaching, and maize yield. The study was carried out at Birfarm, in the Jabitehnan District, Amhara, Ethiopia, throughout the irrigation periods of 2022/23 and 2023/24. The experiment used a (RCBD) with three replications testing five application depths to apply irrigation (50 %, 75 %, 100 %, 125 % and 150 % ETc). ANOVA was performed to determine the influences of irrigation levels on nutrient uptake and nitrate leaching. Irrigation levels significantly impacted N, P and K uptake. Maximum nutrient uptake occurred at 150 % ETc with higher nutrient uptake observed in the second experimental season. Irrigation levels significantly affected nitrate leaching, with the highest leaching at 150 % ETc. Excessive irrigation increased nitrate leaching, aligning with findings from other studies. Maize yield, thousand grain weight (TGW) and above-ground biomass yield (ABY) were significantly influenced by irrigation depth. Optimal irrigation (100 % ETc) produced the maximum yield of 6.08 and 5.83 tha^-1, the maximum thousand grain weight of 682.51 g and 685.12 g, and the highest above-ground biomass yield of 31.41 and 32.74 tha^-1 in the second and first experiments, respectively, while excessive and deficit irrigation reduced yield. The study highlights the importance of optimizing irrigation depth for nutrient uptake, nitrate leaching and maize yield. While increased irrigation improved nutrient uptake and yield, excessive irrigation led to higher nitrate leaching, emphasizing the need for balanced irrigation practices to enhance productivity and environmental sustainability. Farmers should implement 100%ETc to enhance productivity, ensure efficient nutrient utilization, and protect the environment from the adverse effects of nitrate leaching.