The current rate of groundwater extraction in the United States is unsustainable, making it essential to understand the impacts of limited water use on food production. Here, we integrate a gridded crop model with satellite observations and water survey data to assess the effects of sustainable groundwater withdrawals on US agricultural production. Using the most optimistic assumptions for groundwater extraction, we find that sustainable groundwater use will decrease US irrigated production of maize, soybean, and winter wheat by 20%, 6%, and 25%, respectively. Using more conservative assumptions of groundwater availability, US irrigated production of maize, soybean, and winter wheat will decrease by 45%, 37%, and 36%, respectively. Model uncertainty was assessed by comparing simulations with independent estimates. Seasonal simulated evapotranspiration in agricultural areas between crop models and satellite based estimates (ALEXI) were in agreement (R2 = 0.68 across simulations). Additionally, model simulations of total production per county and average yield were strongly correlated with survey data from the United States Department of Agriculture (R2 ranged 0.82-0.94 for county level production and 0.37-0.54 for yield across crops). These results demonstrate the vulnerability of US agricultural production to unsustainable groundwater pumping, highlighting the difficulty of expanding or even maintaining food production in the face of climate change, population growth, and shifting dietary demands.
Evaluating the Sustainability of Irrigated Agricultural Production in the United States, awarded Spring 2018