This experiment aimed to assess the impact of deficit irrigation on both the quantitative and qualitative yield of forage maize hybrids. The study was structured as a split-plot design, utilizing a randomized complete block design with three replications, at the Agricultural Research Station of Gorgan in the years 2021 and 2022. Deficit irrigation was implemented at four different levels as the main plots, which comprised 100%, 75%, 50%, and 25% of the water requirement. These main plots were further subdivided into subplots, consisting of four hybrid varieties, namely SC703, SC704, ZP548, and BK50. The results showed that the highest total biomass (47,939 kg ha⁻¹) was obtained under 100% water requirement (control) and SC704 hybrid. The reduction in total biomass for the treatments at 75%, 50%, and 25% of the water requirement, when compared to the control treatment, amounted to 3160 kg ha⁻¹ (7%), 21,354.5 kg ha⁻¹ (47.4%), and 35,582.8 kg ha⁻¹ (79.1%), respectively. Deficit irrigation significantly affected qualitative traits except for neutral detergent fiber (NDF) at the level of 1% and increased all quality traits. Accordingly, the highest percentage of crude protein (CP), NDF and acid detergent fiber (ADF) was obtained by hybrid SC703 with 50% water requirement (by 9.20%), hybrid BK50 under 25% water requirement (by 30.73%), and BK50 with 75% water requirement (by 44.03%). The highest water use efficiency (WUE) was observed in 75% of the water requirement (7.79 kg m⁻³). Considering the significant reduction in water consumption (1795 m³ ha⁻¹) achieved with this treatment, it is advisable to recommend irrigation at 75% of the water requirement alongside the cultivation of the SC703 hybrid for forage production in the northern region of Iran.

本试验旨在评估亏缺灌溉对饲用玉米杂交种产量和质量产量的影响。该研究采用裂区设计，采用随机完整区组设计，于 2021 年和 2022 年在戈尔甘农业研究站进行了 3 次重复。在四个不同级别作为主要地块实施了赤字灌溉，其中包括需水量的 100%、75%、50% 和 25%。这些主小区进一步细分为子小区，由四个杂交品种组成，即 SC703、SC704、ZP548 和 BK50。结果表明，在100%需水（对照）和SC704杂交条件下获得了最高的总生物量（47,939 kg ha ^{-1 ）。}与对照处理相比，需水量分别为 75%、50% 和 25% 的处理的总生物量减少量分别为 3160 kg ha ⁻¹ (7%)、21,354.5 kg ha ⁻¹ (47.4%) ) 和 35,582.8 kg ha ^-1 (79.1%)。亏缺灌溉显着影响了除中性洗涤纤维（NDF）以外的品质性状（1%），并增加了所有品质性状。因此，粗蛋白（CP）、NDF和酸性洗涤纤维（ADF）的百分比最高的是需水量50%的杂种SC703（9.20%）、需水量25%的杂种BK50（30.73%）和BK50 需水量为 75%（减少 44.03%）。在需水量的 75% 时观察到最高的水分利用效率 (WUE) (7.79 kg m ^-3 )。考虑到通过这种处理实现了耗水量的显着减少（1795 m ³ ha ^-1），建议在伊朗北部地区种植用于饲料生产的 SC703 杂交种的同时，以需水量的 75% 进行灌溉。