What is in this article?:
- Center pivots contain crop costs
- Center pivot efficiency
- Center pivot technology allows Doug Dunlap, Willcox, Ariz., to farm more effectively. He estimates his water efficiency at about 90 percent.
- Center pivot use boils down to efficiency — lowering costs.
- Dunlap’s crop yields are 15 percent to 20 percent higher with pivot irrigation.
- Pivots allow for utilization of minimum tillage.
Center pivot efficiency
Dunlap says center pivot use in his area boils down to efficiencies — which keeps more money in the grower’s wallet.
“I get more uniformity with pivots versus row water. My crop yields are 15 percent to 20 percent higher with pivot irrigation.”
Pivots also allow him to utilize minimum tillage.
“With row water, we had to get the land black, landplane it, and list it, which meant a lot of trips across the field,” Dunlap says. “Now, we can disk the ground a couple of times and then plant corn.”
An installed quarter-mile-long center pivot system costs about $70,000 on average, he says.
The pivot’s speed is adjustable. A 16-hour complete circle applies about three-tenths inch of water.
Some herbicides, fungicides, and pesticides are chemigated through the pivot system, which is particularly effective on Dunlap’s chile crop.
“I can apply water that includes a pesticide to kill nematodes in the chile,” he says.
Center pivot irrigation is slowly gaining in popularity in the West. Acceptance has been slow for a number of reasons.
“A lot of land in the West is high dollar land, where growers don’t want to leave land out of production (the circle corners),” Dunlap says.
“The cost of the center pivot is probably another factor, and the technology is still new to some people. But, the technology in new pivot systems is easy to operate.”
Early problems with center pivots in the U.S. included tires becoming stuck in wet ground. Farmers in Cochise County have learned ways around that, including planting cover crops and utilizing minimum tillage instead of ripping the ground.
Drip irrigation is also catching on in the West, but Dunlap says it is not a good fit for his area due to the large numbers of gophers and mice that chew on drip tape.
Robert Call, University of Arizona area horticulture agent for Cochise County, says the Willcox area has about 500 center pivot systems, which irrigate about 90 percent of the county’s crop acreage.
Pivot system water efficiency ranges from 80 percent to 90 percent, depending on the system setup and soil conditions, Call says. Systems can be automated and controlled by cell phone or computer.
“The efficiency factor depends on the drops, plus crop canopy height, wind, and cloud cover,” he says. “During the summer monsoon (rainy) season, the sky can be cloudy until sunset.”
Call says center pivots are adaptable to small grains, corn, hay, and other crops popular in the area.
Edward Martin, irrigation specialist, University of Arizona, Tucson, says, “One advantage that growers in Cochise County have is that most center pivot systems are fairly new and incorporate the latest technology. One person can manage several hundred acres at a time.”