Sustainable Use of Groundwater May Dramatically Reduce Irrigated Production of Maize, Soybean, and Wheat
Sustainable Use of Groundwater May Dramatically Reduce Irrigated Production of Maize, Soybean, and Wheat
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DOI：
10.1029/2021ef002018
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发表时间：
2021-12
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通讯作者：
José R. López;J. Winter;J. Elliott;A. Ruane;C. Porter;G. Hoogenboom;Martha C. Anderson;C. Hain
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作者：
José R. López;J. Winter;J. Elliott;A. Ruane;C. Porter;G. Hoogenboom;Martha C. Anderson;C. Hain
美国 (US) 的地下水开采是不可持续的，因此了解有限用水对灌溉农业的影响至关重要。为了加深这种理解，我们将网格作物模型与卫星观测、补给估算和水资源调查数据相结合，以评估可持续地下水抽取对美国灌溉农业生产的影响。网格作物模型与基于卫星的蒸散量估计值（R2 = 0.68）以及美国农业部的调查数据一致（县级产量的 R2 = 0.82-0.94，县级产量的 R2 = 0.37-0.54）。使用地下水开采量等于有效含水层补给率的乐观假设，我们发现地下水的可持续利用使美国玉米、大豆和冬小麦的灌溉产量分别减少了 20%、6% 和 25%。使用更为保守的地下水可用性假设，美国玉米、大豆和冬小麦的灌溉产量分别减少了 45%、37% 和 36%。模拟损失的范围广泛是由地表水和地下水相互作用的相当大的不确定性以及对可持续性的许多方面的考虑造成的。我们的研究结果表明，美国灌溉农业容易受到不可持续的地下水抽取的影响，突显出在气候变化、人口增长和饮食需求变化的情况下扩大甚至维持灌溉粮食生产的难度。这些发现是基于通过休耕灌溉农田减少抽水；然而，替代性的减少抽水策略或作物遗传和灌溉方面的技术进步可能会产生不同的结果。
Groundwater extraction in the United States (US) is unsustainable, making it essential to understand the impacts of limited water use on irrigated agriculture. To improve this understanding, we integrated a gridded crop model with satellite observations, recharge estimates, and water survey data to assess the effects of sustainable groundwater withdrawals on US irrigated agricultural production. The gridded crop model agrees with satellite‐based estimates of evapotranspiration (R2 = 0.68), as well as survey data from the United States Department of Agriculture (R2 = 0.82–0.94 for county‐level production and 0.37–0.54 for county‐level yield). Using the optimistic assumption that groundwater extraction equals effective aquifer recharge rate, we find that sustainable groundwater use decreases US irrigated production of maize, soybean, and winter wheat by 20%, 6%, and 25%, respectively. Using a more conservative assumption of groundwater availability, US irrigated production of maize, soybean, and winter wheat decreases by 45%, 37%, and 36%, respectively. The wide range of simulated losses is driven by considerable uncertainty in surface water and groundwater interactions, as well as accounting for the many aspects of sustainability. Our results demonstrate the vulnerability of US irrigated agriculture to unsustainable groundwater pumping, highlighting the difficulty of expanding or even maintaining irrigated food production in the face of climate change, population growth, and shifting dietary demands. These findings are based on reducing pumping by fallowing irrigated farmland; however, alternate pumping reduction strategies or technological advances in crop genetics and irrigation could produce different results.