Evaluation of fertigation management impacts of surface drip irrigation on reducing nitrate leaching using numerical modeling

The objective of this study was to investigate the impacts of fertigation strategies on nitrate leaching and its uptake into maize plants. Field experimental data were employed to calibrate a numerical model (HYDRUS 2D/3D) for a surface drip irrigation system in a sandy clay loam soil. The calibrated model was used to simulate nitrate plant uptake and its leaching in different fertigation scenarios based on various fertigation durations and different start times of fertigation. Finally, nitrogen plant uptake was compared with maize N requirement during growth stages in two fertigation frequency scenarios. These simulations were also performed in sandy loam soil. The results show that, if fertigation is done at the end of irrigation, nitrate leaching in shorter fertigation duration will be less than the leaching in longer fertigation duration. However, in the case of fertigation at the beginning of irrigation, the nitrate leaching is higher if the fertigation duration is short, and vice versa. Furthermore, reducing the number of fertigation events in the sandy clay loam soil increases the nitrate plant uptake. However, in the sandy loam soil, a lesser number of fertigation events reduce nitrate uptake.