Knowledge about potato yield responses to water supply at low, optimum and high levels is required to inform supplemental irrigation (SI), but short-term irrigation experiments may not produce this knowledge in a humid environment because of the difficulty in accurately controlling water supply with uncertain precipitation. This study was conducted to characterize potato yield responses to water supply by treating the 2001–2018 potato yields in Prince Edward Island (PEI), Canada as the results of an un-replicated irrigation experiment with growing season (GS) precipitation as irrigation water supply and utilize the results to inform SI. Yield responses to GS precipitation followed a second-order polynomial regression, with 88% of yield variation being explained by GS precipitation. The yield increased from 19.2 to 33 Mg/ha as GS precipitation increased from 150 to 360 mm, responded relatively insensitively (33–35 Mg/ha) when GS precipitation was between 360 and 460 mm and decreased as the precipitation exceeded 460 mm. Water deficiency/excess calculated as the difference between GS precipitation and evapotranspiration of the potato plant (ET_c) indicates that 16 of the 18 seasons required SI of 30–300 mm while four of the 18 seasons required soil dewatering of 30–100 mm to maximize potato yields. The yield regression equation predicted that SI using a center-pivot system could generate net profit in an extremely dry year, but it is unlikely to do so in most years. Depending on the year, SI could use anywhere between 2.6% and 23% of annual average recharge in an intensively potato-cropped watershed, which can impose high stress on the groundwater discharge-dependent ecosystems in a very dry season. This study demonstrates that long-term potato yield responses to precipitation in a humid climate can provide important information to inform SI management and water allocation.

需要了解马铃薯产量对低水、最佳水和高水供应的反应，以告知补充灌溉 (SI)，但短期灌溉实验可能无法在潮湿环境中产生这些知识，因为难以准确控制水供应降水不确定。本研究旨在通过将加拿大爱德华王子岛 (PEI) 2001-2018 年马铃薯产量作为非复制灌溉实验的结果来表征马铃薯产量对供水的响应，其中生长季 (GS) 降水作为灌溉供水并利用结果通知 SI。对 GS 降水的产量响应遵循二阶多项式回归，88% 的产量变化由 GS 降水解释。产量从 19 增加。随着 GS 降水量从 150 增加到 360 毫米，2 到 33 毫克/公顷，当 GS 降水量在 360 到 460 毫米之间时反应相对不敏感（33-35 毫克/公顷），随着降水量超过 460 毫米而减少。水分缺乏/过量计算为马铃薯植株的 GS 降水和蒸散量 (ET) 之间的差异_c ) 表明 18 个季节中有 16 个需要 30-300 毫米的 SI，而 18 个季节中有四个需要 30-100 毫米的土壤脱水，以最大限度地提高马铃薯产量。收益率回归方程预测，使用中心枢轴系统的 SI 可以在极其干旱的年份产生净利润，但在大多数年份不太可能这样做。视年份而定，SI 可以使用马铃薯密集种植流域年平均补给量的 2.6% 至 23%，这会对非常干旱的季节依赖地下水排放的生态系统造成很大压力。这项研究表明，在潮湿气候下，马铃薯产量对降水的长期响应可以为 SI 管理和水资源分配提供重要信息。