Midwest-style irrigation making crop circles in California

A frequent research collaborator with UC Cooperative Extension, West Side farmer John Diener made the front page of the Fresno Bee on Sunday with a story about the potential for water savings with a center-pivot irrigation system.

On airplane flights over middle America, passengers have for decades seen large circles made by center-pivot irrigation on the quilt of farmland landscape below. The system is just beginning to catch on in California, and Diener, working with UC, is an early adopter.

Diener told Bee reporter Robert Rodriguez that the pivot system is 10 to 20 percent more efficient than furrow irrigation.

"One of our challenges is how to water more efficiently and in a way where you can get a comparable or better yield from a conventional system," Diener was quoted in the story. "That is what we are after."

The article said growers searching for ways to improve their irrigation efficiency have packed meetings held by private companies, Fresno State and University of California researchers in recent months.

UC Davis Cooperative Extension vegetable crops specialist Jeff Mitchell is leading the center-pivot charge for UC. He said the irrigation system didn’t prosper in California when the technology was first introduced in the 1950s for a variety of reasons. Center-pivot systems weren't able to deliver enough water for plants sweltering in the valley’s summer heat and water didn’t infiltrate quickly enough to prevent runoff.

But the growing popularity of conservation tillage has farmers taking another look at center pivots. Under conservation tillage systems, crops are planted in the residue of a previous season crop or a cover crop. The residue keeps the soil more porous, allowing for quicker water infiltration. In addition, the dead plant material on the soil surface reduces evaporation, so farmers don’t need to apply as much water.

In an eight-acre West Side research plot, scientists are studying crop productivity, water use efficiency, economics and potential for reducing dust emissions with center-pivot irrigation. They will compare the results with crops grown under alternative practices, such as no-till production in a standard furrow-irrigated field and a furrow-irrigated plot managed with standard tillage practices.

Aerial view of center-pivot irrigation.

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