By Trina Kleist
Report: Fallow farmland brings few benefits, but incurs costs
California’s San Joaquin Valley produces an enormous share of the nation’s fruits, nuts and vegetables. But it takes an unsustainable amount of groundwater to do it. New state rules aimed at reducing groundwater use are expected to force up to 20 percent of the valley’s irrigated fields out of production – a blow to farmers and communities.
Now, UC Davis research shows those lands could remain viable if farmers plant winter grain crops. When managed properly, small grains such as wheat, triticale, barley, oats and rye can grow during the cool season, using little irrigation and relying mostly on seasonal rain. The strategy would help farmers keep land productive even during dry winters, without threatening groundwater supplies.
Five years of study from teams led by Mark Lundy and Cameron Pittelkow, both in the Department of Plant Sciences, also show winter grains may help recharge depleted groundwater – even more than taking the land out of production. Their research is part of a new report by the Public Policy Institute of California, or PPIC, which looks at how farmers can comply with the state’s historic Sustainable Groundwater Management Act, passed in 2014.
“We really drilled down into the water use of the winter crops and how that compares to the fallow system,” said Lundy, an associate professor of Cooperative Extension and a co-author on the report. “There’s not been that direct comparison made very frequently or rigorously.”
Small grains can be planted in the fall when it’s cool. They need minimal irrigation to get started, then winter rains take over. If rain is plentiful, farmers can harvest and sell the grain. If not, they can harvest early for animal feed and sell it to nearby dairy and beef operations. During drought, grains offer all the benefits of a winter cover crop, with minimal investment. During wet years, winter crops could even help recharge depleted aquifers.
The report also drew on research by Cooperative Extension specialist Jeff Mitchell and Amélie Gaudin, also in the department.
Source : ucanr.edu