Sustainable Use of Groundwater May Dramatically Reduce Irrigated Production of Maize, Soybean, and Wheat. Issue 1 (27th December 2021)

• Record Type: Journal Article
• Authors: Lopez, Jose R.; Winter, Jonathan M.; Elliott, Joshua; Ruane, Alex C.; Porter, Cheryl; Hoogenboom, Gerrit; Anderson, Martha; Hain, Christopher
• Is Part Of: Earth's future. Volume 10:Issue 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-27
• Subjects: sustainability -- irrigation -- water use -- crop -- irrigated agriculture; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2021EF002018
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: 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 ( R 2 = 0.68), as well as survey data from the United States Department of Agriculture ( R 2 = 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. Plain Language Summary: Irrigated agriculture in the United States (US) is depleting groundwater in some regions, which will eventually reduce the amount of water available for growing crops. We used a computer model to assess the impacts of sustainable water use on US irrigated agriculture. We first compared simulated crop production and water use with observed data over 5 years to evaluate the accuracy of the computer model. Simulated yield and crop water use were in good agreement with reported yields from the United States Department of Agriculture and satellite evapotranspiration estimates. We then modeled different water restriction scenarios and found that under the most optimistic scenario, US production of irrigated maize, soybean, and winter wheat decreases by 20%, 6%, and 25%, respectively. However, under the most pessimistic scenario, US production of these irrigated crops will decrease by 45%, 37%, and 36%, respectively. Overall, our simulations of different water restriction scenarios show the vulnerability of US irrigated agricultural production to reduced groundwater pumping, and highlight the difficulty of expanding or even maintaining irrigated food production across the country. Key Points: We integrate a crop model with satellite observations and survey data to simulate sustainable groundwater use for agriculture Optimistic sustainable groundwater use may decrease US irrigated production of maize, soybean, and winter wheat by 20%, 6%, and 25% Pessimistic sustainable groundwater use may decrease US irrigated production of maize, soybean, and winter wheat up to 45%, 37%, and 36%