A deficit irrigation trial was conducted with field-grown Cabernet Sauvignon grapevines in the Columbia Valley of southeastern Washington. Four irrigation regimes were applied in four replicated blocks to replace various fractions of crop evapotranspiration (ETc) between fruit set and harvest. These treatments were designated ET100 (100% ETc), ET70 (70% ETc), ET25 (25% ETc), and ET25/100 (25% ETc before veraison and 100% ETc thereafter). Leaf water status and gas exchange, canopy growth and microclimate, and yield formation were evaluated over three years. Despite yearly variation in growing season temperatures, irrigation treatment effects were consistent among years. Overall, deficit irrigation did not enhance water-use efficiency. The ET100 and ET70 regimes rarely differed in vine physiology and performance. The ET25 regime, however, strongly limited gas exchange and led to a decline in vine capacity and productivity, suggesting that this degree of water deficit was economically unsustainable. In addition, this treatment was associated with small berries on small clusters, very high fruit-zone sunlight exposure, and elevated cluster temperature. The ET25/100 regime was generally intermediate in vine physiology, growth, and yield components. This treatment resulted in open canopies and small berries without the penalty in vine capacity and yield that was incurred with ET25. Potential effects of water deficit on fruit composition may be related to altered canopy size and microclimate, in addition to decreased berry size.

中文翻译：

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缺水灌溉改变了葡萄的生长、生理和果实小气候

对华盛顿东南部哥伦比亚谷的田间种植赤霞珠葡萄藤进行了亏缺灌溉试验。在四个重复的区块中应用四种灌溉制度，以替换坐果和收获之间作物蒸散量 (ETc) 的不同部分。这些处理被指定为 ET100 (100% ETc)、ET70 (70% ETc)、ET25 (25% ETc) 和 ET25/100（在 veraison 之前为 25% ETc，之后为 100% ETc）。对叶片水分状况和气体交换、冠层生长和小气候以及产量形成进行了三年的评估。尽管生长季节温度每年都在变化，但灌溉处理效果在各年间是一致的。总体而言，亏缺灌溉并未提高用水效率。ET100 和 ET70 方案在葡萄树生理和性能方面几乎没有差异。然而，ET25 制度，严重限制了气体交换并导致葡萄树容量和生产力下降，表明这种程度的缺水在经济上是不可持续的。此外，这种处理与小簇上的小浆果、非常高的果实区阳光照射和升高的簇温度有关。ET25/100 方案通常在葡萄树生理、生长和产量组成方面处于中间状态。这种处理导致开放的树冠和小浆果，而没有 ET25 导致的葡萄藤容量和产量的损失。水分亏缺对果实组成的潜在影响可能与树冠大小和小气候的改变有关，以及浆果大小的减小。此外，这种处理与小簇上的小浆果、非常高的果实区阳光照射和升高的簇温度有关。ET25/100 方案通常在葡萄树生理、生长和产量组成方面处于中间状态。这种处理导致开放的树冠和小浆果，而没有 ET25 导致的葡萄藤容量和产量的损失。水分亏缺对果实组成的潜在影响可能与树冠大小和小气候的改变有关，以及浆果大小的减小。此外，这种处理与小簇上的小浆果、非常高的果实区阳光照射和升高的簇温度有关。ET25/100 方案通常在葡萄树生理、生长和产量组成方面处于中间状态。这种处理导致开放的树冠和小浆果，而没有 ET25 导致的葡萄藤容量和产量的损失。水分亏缺对果实组成的潜在影响可能与树冠大小和小气候的改变有关，以及浆果大小的减小。这种处理导致开放的树冠和小浆果，而没有 ET25 导致的葡萄藤容量和产量的损失。水分亏缺对果实组成的潜在影响可能与树冠大小和小气候的改变有关，以及浆果大小的减小。这种处理导致开放的树冠和小浆果，而没有 ET25 导致的葡萄藤容量和产量的损失。水分亏缺对果实组成的潜在影响可能与树冠大小和小气候的改变有关，以及浆果大小的减小。