They Use Pivot Irrigator To "Flood Out" Gophers

They Use Pivot Irrigator To "Flood Out" Gophers IRRIGATION Irrigation Systems 21-4-28 Alfalfa growers on two Nevada farms are using their center pivot irrigation systems to solve serious problems with pocket gophers. Ron and LaVonne Selbach of Amargosa Valley, and Gary Tompkins, Winnemucca, used slightly different methods but got the same results. In 1995, the Selbachs read an article in Hay & Forage Grower magazine about an-other Nevada grower who rid alfalfa fields of gophers by flooding them out of their bur-rows using lengths of gated irrigation pipe. They decided there had to be a way to do the same thing with their pivots. So they removed the sprinklers from the down spouts on four pivots and attached lengths of surplus fire hose to each outlet. The Selbachs turned on the pivots last January and February, with the hoses pouring streams of water onto the ground. Employees walking under the pivots used the hoses to direct water right into gopher bur-rows. "The farm dogs proved to be a real as-set," says Ron. "One dog caught 22 gophers one morning." After the dogs left the field, hawks and crows took over, and coyotes worked the fields at night. "Every gopher that came up got it," LaVonne recalls. "It was quite an interesting sight. It has knocked down the gopher activity by about 80 percent," she adds. "We did go back and put some poison grain in the holes, and we plan to do some trapping." After flooding the fields they used a harrow to smooth the ground. "That way, we can set traps wherever we see new mounds." Last year Tompkins spent about $98,000 trapping gophers on 1,700 acres of alfalfa. "We had eight trappers and they couldn't keep up. This year we've got three trappers, and they're just hitting the hot spots." Tompkins' 10 pivots, running 24 hours a day, each took 20 days to make a complete circle. Two pumps pushed a total of 2,000 gallons per minute through each pivot. "Because we chose to flood the gophers in November and December, our irrigation cost increased by $13,000 because of the higher electricity rate at that time of year. But the water wasn't wasted because we saturated the soil going into winter. The water was sometimes 4 in. deep on the ground." The heavy watering caused gopher bur-rows to collapse. "There would actually be trails of collapsed tunnels in the field." Tompkins ran the pivots only when temperatures were cold enough for emerging gophers to die from hypothermia.

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