To reduce the harmful environmental effects of fertilizer application in irrigated agriculture, evaluating alternative fertigation management practices is essential in different irrigation systems. This study aims to evaluate the water movement and nutrient transport in the corn root zone under subsurface drip irrigation (SDI) using the HYDRUS-2D model in different irrigation and fertigation management practices. For this purpose, a 2-year field experiment was conducted in the growing seasons of 2018 and 2019. Three different irrigation levels, three fertilizer application frequencies, and two fertilizer injection times during each irrigation event were selected as different treatments. Irrigation levels included full irrigation (FI) and two deficit irrigations (DI) at 75% and 50% of the plant’s net requirement (DI₇₅ and DI₅₀). Three different fertigation frequencies including weekly, once every 2 weeks, and local recommendations in three splits were considered, and the fertilizer was injected at the end and middle of each fertigation event. HYDRUS (2D) was calibrated based on the conducted field experiments and the calibrated model was then utilized to simulate nitrate leaching and N uptake by corn in different treatments. The results indicated that the highest nitrate root uptake occurred in fertilizer application with three splits in all irrigation levels. N uptake in weekly and once every 2 weeks treatment in full irrigation was about 46% of the total applied fertilizer. However, reducing fertigation frequency to three splits increased N uptake to 59% in the studied fine-textured soil. As a result, it reduced the amount of residual nitrate in the soil at the end of the growing season which has high leaching potential. The findings of this study are significant in reducing the environmental effects of chemical fertilizer abuse and increasing the efficiency of fertilizer uptake by corn in SDI.

为了减少灌溉农业中施肥对环境的有害影响，评估不同灌溉系统的替代灌溉施肥管理实践至关重要。本研究旨在使用 HYDRUS-2D 模型在不同的灌溉和灌溉施肥管理实践中评估地下滴灌 (SDI) 下玉米根区的水分运动和养分输送。为此，在2018年和2019年的生长季进行了为期2年的田间试验，选择3种不同的灌溉水平、3种施肥频率以及每次灌溉期间的2次施肥次数作为不同的处理。灌溉水平包括完全灌溉(FI) 和两次赤字灌溉(DI)，分别为植物净需求的75% 和50%（DI ₇₅和DI ₅₀）。考虑了三种不同的灌溉施肥频率，包括每周一次、每两周一次和分三批当地建议，并在每次灌溉施肥事件结束和中间注射肥料。根据田间实验对HYDRUS (2D)进行校准，然后利用校准后的模型模拟不同处理下玉米的硝酸盐淋溶和氮素吸收。结果表明，在所有灌溉水平下，根系吸收硝酸盐的最高发生在施肥时，分三批。在充分灌溉的情况下，每周和每两周一次的氮吸收量约为施肥总量的46%。然而，在所研究的细质地土壤中，将灌溉施肥频率减少至三次，氮吸收量增加至 59%。因此，它减少了生长季节结束时土壤中残留硝酸盐的量，而土壤中的硝酸盐具有很高的淋滤潜力。这项研究的结果对于减少化肥滥用对环境的影响和提高SDI玉米对肥料的吸收效率具有重要意义。