Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity

Irrigation contributes significantly to U.S. agricultural output and production value. In 2017, irrigated farms accounted for more than 54 percent of the total value of crop sales. Irrigation allows for agricultural production in arid regions where precipitation is insufficient to meet crop water requirements. In more humid regions with variable rainfall, irrigation supplements available soil moisture and provides a critical buffer against periodic drought during the crop growing season. However, surface water supply shortfalls during prolonged drought are increasingly taxing the ability of regional water systems to meet the demands of the irrigation sector—as well as industry, municipal use, recreation, and environ-mental needs. The irrigation sector responded by increasing its reliance on groundwater. This response raises sustainability concerns, as groundwater levels in many major aquifers supporting irrigated agriculture are in decline across the United States. The resiliency of irrigated agriculture under projected climate change will depend on how the sector—and the institutions that influence water supply and use—adapts to increasing water scarcity. Regional adaptation to increasingly limited water supplies may involve a combination of measures. These measures include: continued shifts in area irrigated, increased irrigation efficiency through system upgrades, enhanced water management practices, changes in regional cropping patterns, and shifts in water supply sources, including potentially novel sources of irrigation water such as recycled or reclaimed water