While efforts are underway to augment water supplies-for instance by increasing groundwater recharge-bringing basins into balance is also likely to entail reductions in irrigated crop acreage. SGMA requires local groundwater sustainability agencies (GSAs) to end groundwater overdraft by 2040, while addressing the associated undesirable effects.Īs SGMA implementation unfolds, it will have extensive impacts on the San Joaquin Valley’s agricultural landscapes. In response to the undesirable effects of overdraft such as dry wells, land subsidence, and declining drought reserves, California passed the landmark Sustainable Groundwater Management Act (SGMA) in 2014. Groundwater overdraft in the San Joaquin Valley-the state’s largest farming region-has long been a problem. In many parts of California, agricultural production has relied for decades on largely unregulated groundwater pumping. Various research efforts would facilitate the development of water-limited cropping as an alternative to widespread land idling, including research to improve crop modeling for valley conditions, improve the performance of water-limited cropping systems, expand the portfolio of water-limited crops, understand key interactions such as salinity and weed pressure, and understand the market potential and price/cost thresholds for the economic viability of water-limited crops. Further work is needed to test water-limited cropping in the valley.These include state and federal programs to compensate growers for the public benefits created by water-limited crops, local groundwater budgets that account for the net water use from fallowing, and regional planning that considers water-limited crop management among the suite of alternatives available for lands transitioning out of irrigated production. Supportive policies could expand opportunities for water-limited cropping.Potential benefits from keeping crops in the ground include reduced dust pollution risk and better water infiltration and soil quality relative to idled land, with similar or only slightly more water consumption. Co-benefits from water-limited crops go beyond direct financial returns.Instead, early harvests of forage (e.g., hay or silage for livestock) may be a more profitable use of water and offer the flexibility to produce grain in good water years. Waiting until grain maturity to harvest a winter cereal crop may not be the best management strategy under water-limited conditions. Forage makes better use of limited water than grain.Other crops may also be viable with supplemental irrigation, as long as irrigation systems are capable of delivering small volumes without undue expense. When precipitation can be supplemented by 4–8 inches of irrigation, models show that winter wheat establishment improves dramatically even in drier parts of the valley-and growers’ experience tends to align with this finding. but small amounts of irrigation can have a big impact on crop establishment. Yet highly variable rainfall patterns and low overall water availability make dryland grain production risky reliable harvests are likely only possible in the wetter northern parts of the valley. Crops such as winter wheat grown using only precipitation to supply crop water requirements were once commonplace in the valley. Strictly dryland crops have limited scope in today’s San Joaquin Valley.Although water-limited agriculture faces large hurdles, some promising aspects warrant further exploration. Rather than widespread land idling-which comes with unintended consequences such as dust, weeds, pests, and soil degradation-a switch from summer irrigated crops to winter crops produced with limited water (including winter cereals and forage crops, among others) might keep some of this land in production. As groundwater sustainability measures are implemented and water scarcity increases, at least half a million acres are projected to come out of irrigated production in the San Joaquin Valley, the state’s agricultural heartland. The rollout of California’s Sustainable Groundwater Management Act (SGMA) is altering the state’s agricultural landscape.
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