New sprinkler costs high, but so are advantages

Irrigators discuss environment, water quality concerns

Patricia R. McCoy
Capital Press

January 8, 2009

For some growers, flood irrigation is still a viable alternative to using mechanical sprinkler systems, but an Oregon State University Extension agent says some of the problems of converting can be overcome.

Sprinkler systems, especially the massive center-pivots commonly seen in some areas, aren't as common in Malheur County, Ore., or even Southwest Idaho, for several reasons.

Sprinklers are expensive and not easy to install on small, oddly-shaped fields found in the area, Steve Norberg, Malheur County Extension agent, said in a phone interview.

Sprinkler systems do have advantages, Norberg said. Norberg talked about those advantages to a group of about 70 producers at an irrigation conference on Tuesday, Jan. 6, in Ontario.

"There are some water savings with sprinklers compared to flood irrigation, but that's usually not a big issue for growers in our immediate area," Norberg said at the conference. "However, there are environmental and water quality concerns with flood irrigation."

Sprinklers send less irrigation water running off fields or percolating down through the soil profile, carrying topsoil, phosphorus and nitrates with it, he said.

"In the Willow Creek community, northwest of Ontario, there were problems with high levels of fecal coliform in runoff water," Norberg said. "The problem was bacterial contamination caused by so much livestock in the area."

Such issues are why the Malheur Watershed Council and the Willow Creek Working Group began developing grants to help growers cover the costs of sprinkler systems.

Those costs can range from $700 to $2,000 an acre, depending on field size, which brand name system is chosen and how elaborate of a system is installed, said Kurt Roman, an equipment dealer, in a phone interview. Roman was also one of the speakers at the conference in Ontario.

"There are economies of scale, because that estimate includes certain fixed costs for the pump, electrical wiring and control system that come into play no matter how small or large the field," he said. "Some of the costs also vary with how many years the buyer must finance his purchase. You have to factor in interest payments on a loan."

Most growers are willing to install sprinklers, if they can solve the financial problem, Norberg said.

"Environmentally, most guys would like to do it," he said. "Sprinklers have other advantages, too. If you have trouble finding labor, this is a way to mechanize and handle more acreage by yourself. If you couple a modernized irrigation system with reduced tillage, there can be still more savings, in terms of the number of equipment trips across a field."

Sprinklers let growers incorporate chemigation into their management, cutting fuel costs, thanks to reduced numbers of tractor trips across a field, he said.

Modernizing irrigation isn't a panacea, though. Sprinklers can deposit water in the necks of onions, a major cash crop in the area. That moisture can lead to Botrytis allii, or neck rot, a fungal disease. Even if the disease doesn't develop in the field, that water makes it harder to dry the onion down so it will store well, Norberg said.

Sprinkler water splashing on alfalfa seed plants also doesn't help preserve the seed for future harvest, Norberg said.

"We're still doing research on onions to see how much of a problem sprinklers are in relationship to Botrytis allii ," he said. "Lynn Jensen, my fellow county agent, is also looking at applying herbicides through chemigation, particularly to control yellow nutsedge, a major problem in this area. We hope we can gradually solve all these problems."

Staff writer Pat McCoy is based in Boise. E-mail: pmccoy@capitalpress.com.