Dryland winter rapeseed (Brassica napus L.) produced in the semi‐arid regions of Turkey has variable yields. Supplemental irrigation alleviates the adverse effects of soil moisture stress on yield during drought periods. To determine the influence of irrigation timing on yield stability, a 3‐yr, on‐farm irrigation experiment was conducted to determine the effects of supplemental irrigation on rapeseed yield and yield components in a semi‐arid environment. The field experiment considered the influence of six irrigation quantities applied at three growth stages (vegetative, flowering, and early ripening) on rapeseed yield and quality. Supplemental irrigation improved rapeseed yield compared with cultivation under rainfed conditions throughout the three experimental years. Although the greatest seasonal evapotranspiration and rapeseed yields were observed with full irrigation, the highest economic rate and most efficient irrigation rate were for the optimum level to be applied at flowering. Protein content, oil content, and fatty acids increased with irrigation and were highest for the full‐irrigation treatment. Irrigation should be applied when 50% of available soil moisture has been consumed in the effective root zone at the early flowering stage. This timing enhances the water use efficiency and yield potential of rapeseed without reducing quality and could be highly beneficial for semi‐arid regions.

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补充灌溉对油菜产量和品质参数的影响

旱地冬季油菜籽（甘蓝型油菜L.）在土耳其半干旱地区生产，单产可变。补充灌溉减轻了干旱时期土壤水分胁迫对单产的不利影响。为了确定灌溉时间对产量稳定性的影响，进行了为期3年的农田灌溉实验，以确定半干旱环境中补充灌溉对油菜籽产量和产量构成的影响。田间试验考虑了在三个生长阶段（营养，开花和早熟）施用六个灌溉量对油菜产量和品质的影响。与在整个三个实验年中在雨养条件下种植相比，补充灌溉提高了油菜籽的产量。尽管在充分灌溉下观察到最大的季节性蒸散量和油菜籽产量，最高的经济效率和最有效的灌溉速率是要在开花时应用的最佳水平。蛋白质含量，油含量和脂肪酸含量随灌溉而增加，在全灌溉处理中最高。当开花初期有效根区消耗了50％的可用土壤水分时，应进行灌溉。该时间安排可提高油菜的水分利用效率和增产潜力，而不会降低品质，对半干旱地区可能非常有利。当开花初期有效根系消耗了50％的可用土壤水分时，应进行灌溉。该时间安排可提高油菜的水分利用效率和增产潜力，而不会降低品质，对半干旱地区可能非常有利。当开花初期有效根区消耗了50％的可用土壤水分时，应进行灌溉。该时间安排可提高油菜的水分利用效率和增产潜力，而不会降低品质，对半干旱地区可能非常有利。