Regulated deficit irrigation (RDI) during hull-split can reduce water applied in almond orchards. Strategies for imposing RDI in almond orchards with multiple varieties with different hull-split schedules have not been extensively developed. Commonly, irrigation system design requires the same irrigation schedule for all varieties in the orchard. A 2-year study evaluated the impacts of two different regulated deficit irrigation strategies in an almond orchard with Butte, Aldrich, and Nonpareil varieties in the Sacramento Valley of California, USA. The two strategies were (1) RDI in all varieties during Nonpareil hull-split timing and (2) RDI according to variety-specific hull-split timing. The two levels of irrigation were 50 % and 75 % of potential crop evapotranspiration (ET_c) replacement during the hull-split period. Results show that the kernel thickness of the Aldrich almonds increased under 75 % ET_c irrigation replacement during the Aldrich hull-split period compared to 75 % ET_c and 50 % ET_c irrigation replacement during the Nonpareil hull-split period. In the Butte almonds, 75 % ET_c and 50 % ET_c irrigation replacement during variety-specific hull-split reduced the fraction of sealed shells of the Butte variety compared to 75 % ET_c and 50 % ET_c irrigation replacement during the Nonpareil hull-split period. This study demonstrated that an irrigation system design that allows for the independent irrigation scheduling of each variety can change the almond physical quality in the Butte and Aldrich varieties. RDI according to variety-specific hull-split did not result in significant marketable kernel yield improvements after two years of imposing the irrigation strategies. More research should be conducted for different orchard designs, varieties, and climates.

分壳期间调节亏缺灌溉 (RDI) 可以减少杏仁园的用水量。尚未广泛制定在具有不同壳裂时间表的多个品种的杏仁园中实施 RDI 的策略。通常，灌溉系统设计要求果园中所有品种的灌溉时间表相同。一项为期 2 年的研究评估了美国加利福尼亚州萨克拉门托谷的一个杏仁园中两种不同的调节亏缺灌溉策略的影响，该园种植了 Butte、Aldrich 和 Nonpareil 品种。这两种策略是（1）Nonpareil 拆壳时间期间所有品种的 RDI 和（2）根据特定品种拆壳时间的 RDI。两种灌溉水平分别为潜在作物蒸散量的 50 % 和 75 % ( ET _c) 在船体拆分期间更换。结果表明，在Aldrich 分壳期，75% ET _c灌溉替代品与 75% ET _c和 50% ET _c在 Nonpareil 分壳期灌溉替代品相比，Aldrich 杏仁的籽粒厚度增加。在 Butte 杏仁中，与 75 % ET c 和 50 % ET c 相比，在特定品种的壳裂过程中 75 % ET _c和₅₀ % ET c 灌溉替代降低了Butte_品种的密封_壳比例Nonpareil 船体分裂期间的灌溉更换。这项研究表明，允许每个品种独立灌溉计划的灌溉系统设计可以改变 Butte 和 Aldrich 品种的杏仁物理质量。在实施灌溉策略两年后，根据品种特定的外壳分割的 RDI 并未显着提高可销售的籽粒产量。应针对不同的果园设计、品种和气候进行更多研究。