Wednesday, December 1, 2021

UC Davis to lead groundwater, irrigated ag sustainability study

california water well
Water flows from a groundwater well adjacent to a cotton field in Tulare County, California — photo by Vicky Boyd

Researchers from the University of California, Davis, have been awarded a $10 million grant by the U.S. Department of Agriculture’s National Institute of Food and Agriculture to find ways to sustain irrigated agriculture while improving groundwater quantity and quality in the Southwest under a changing climate.

Isaya Kisekka, associate professor of agrohydrology and irrigation at UC Davis, is leading a team of more than two dozen researchers. They include climate, plant and soil scientists; hydrologists; engineers; economists, and educators and Extension specialists from UC Davis and other institutions in California, Arizona and New Mexico. They will develop climate change adaptation management strategies that ensure sustainability of groundwater and irrigated agriculture.

Kisekka says the project team in California will work with Groundwater Sustainability Agencies to develop tools and data to enhance water management at both the farm and groundwater basin scales. Ultimately, they seek to improve crop production and achieve sustainability goals under the state’s Sustainable Groundwater Management Act, which provides a statewide framework to help protect groundwater resources over the long term.

Groundwater quality goals

The research team will also work with grower coalitions to achieve the groundwater quality goals of the Central Valley Salt and Nitrate Management Plan.

“For farmers, the biggest challenge threatening their business is water,” Kisekka said. “Our project is going to develop climate-smart adaptation management practices to help growers achieve their production goals while addressing the co-benefits for the environment and human health. We are going to develop cutting edge tools to manage groundwater quantity and quality as well as study how policies impact behaviors such as water use in agriculture.”

The practices, models and tools developed will be used by growers or their advisers, policymakers, irrigation districts, coalitions and groundwater sustainability agencies to address climate change extremes such as drought or floods.

Growing dependence on groundwater

Growers have increasingly depended on groundwater during multi-year droughts and heat stress. Part of the five-year project includes looking into aquifer systems in California’s Central Valley, central Arizona and the lower Rio Grande basin in New Mexico. These regions have all experienced unprecedented overdraft, which happens when more water is pumped from a groundwater basin than is replaced from sources, including rainfall.

“For a long time, a lot of farmers would use groundwater as an insurance policy whenever there was a drought,” Kisekka said. “The negative consequences of that became obvious: groundwater levels declined, we had subsidence which causes land to sink, we had deterioration in water quality and so on. What are growers going to do when we have another drought like we are now? We have to think more broadly.”

A soil health angle

jeff mitchell
University of California’s Jeff Mitchell compares properties of soil from a field with 20 years of cover crops and no till (left) to soil from a conventionally tilled field without cover crops — photo by Vicky Boyd

He said they will also come up with management practices to improve soil health, develop alternative water supplies and reduce water demand so the region can continue to produce various agriculture commodities.

“We grow crops in California that we cannot shift to another part of the country because they won’t grow well there,” Kisekka said. “We can’t grow almonds in the Southeast where they have a lot of water because they require a certain climate. We want to ensure food and nutritional security of the United States by sustaining irrigated agriculture in the Southwest.”

Educating the next generation

Project researchers will also establish innovative education and Extension programs to teach students of all backgrounds and ages, as well as the public, about the importance of water in agriculture.

“Part of this is to develop educational curriculums from elementary to high school to college, where instructors can pull our modules on water management or sustainable agricultural systems and teach that in their classes,” he said.

While the depletion of groundwater supplies, among other factors, puts major pressure on agricultural operations in the southwestern region, Kisekka hopes the management practices and tools that will be developed during this project will help improve production and resource sustainability and help make California and the country more resilient to climate change.

Ag Water Center of Excellence

UC Davis will establish the Agricultural Water Center of Excellence as part of the grant. This unique Center of Excellence will also have capacity to support agricultural water research, education and extension activities at collaborating institutions with potential impact at local, state, national and international levels.

“We hope at the end of the day we can still grow food in California and the Southwest in general without drying out our groundwater aquifers,” he said. “We have to learn to adapt to climate change. We may not be able to stop it in the short term, but we should be able to adapt.”

Researchers from University of California, Berkeley; UC Agriculture and Natural Resources; Stanford University, California State University, Fresno; University of Arizona; New Mexico State University; USDA Agricultural Research Service (Sustainable Agricultural Water Systems Research: Davis, CA and Water Management and Conservation Research: Maricopa, AZ) and USDA Climate Hub are also participating in the project.

The University of California contributed this report.

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