Irrigation in drought saves crop, but stresses water resources

A water pump gushes into a tank at a demonstration booth at Husker Harvest Days near Grand Island, Neb. (Grant Gerlock, NET News)
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September 20, 2012 - 1:36pm

Irrigation helped some farmers keep the drought at bay over the summer. The water kept fields of corn green long after others withered away. Now those farmers are harvesting the benefits.

Farmers are expecting close to normal yields on their irrigated corn in one of the driest years on record. With corn prices riding high, irrigation offers a competitive advantage. But keeping corn thriving in a drought requires enormous amounts of water and some farmers may be forced to use less in the future as a result.

Photo by Grant Gerlock, NET News

Farmers at Husker Harvest Days expected their irrigated fields to produce a near normal corn crop even in the worst drought in decades.

Photo by Grant Gerlock, NET News

Irrigation companies showed off their newest technology, including control systems that help farmers to be more water efficient.

Graphic by USDA National Ag Statistics Service

Nebraska irrigates more acres of farmland than any other state in the U.S., followed by California and Texas.

At Husker Harvest Days near Grand Island, Neb.hamburgers sizzled on a hot charcoal grill outside a catholic church food stand. The farm show was focused on irrigated agriculture, and Gib Kelly travelled from the north central Neb. town of Page to look at the newest equipment. As he sat down for lunch, Kelly said he wasn’t sure what he would find when he started running his combine through his non-irrigated, or dryland, corn fields.

“The hills were burnt up,” Kelly said. “There were zero bushels on the hills. All the yields came out of the low ground. Yielded 50 bushels (per acre).”

Could have been worse, Kelly said.  But, in fields where he pumps groundwater for irrigation Kelly could bring in three, maybe four times that.

“We’ve been hearing reports over 200 (bushels/acre),” Kelly said. “Probably a lot of guys are hoping for 185-200. That’d be very good.”

Nebraska irrigates more acres of farmland than any other state in the nation. Kansas is also near the top. A University of Nebraska Lincoln studysays the drought could shrink corn yields by 40 percent in dryland fields in Iowa. But yields for irrigated corn in Nebraska may end up only 8 percent lower than expected.

But irrigation has its limits. There were times over the hot summer months when Mark Scott’s groundwater wells couldn’t keep up.

“Sometimes you had to let your wells rest for a couple days and let the water come back into it,” said Scott, who farms near Belgrade, Neb. “Depending on what our underground water aquifer does,  you know, I’m kind of worried about if we’ll have enough water for next year.”

Mike Clements, manager of the Lower Republican Natural Resources District, worries about the same thing. The Lower Republican NRD regulates groundwater irrigation for a portion of south central Nebraska. Clements said farmers in his area saved up water allowances over last couple of wet years, then poured it on this summer.

“When the numbers come in I think they are going to be astronomical,” he said.

And the impact is unmistakable from Clements’ office window, where he can look out and see the Harlan County Reservoir. At least he usually can.

“At the beginning of the irrigation season this reservoir was over a foot into the flood pool. I mean it was full. Plum full,” Clements said. “Now it has dropped about 10 feet. You know, 10 feet out of the top of this lake is a huge, huge volume of water.”

If the Harlan County reservoir stays at its current low-levelit could trigger restrictions on irrigation in southern Nebraska to ensure enough water flows down the Republican River to farmers in Kansas.

Linda Fox is already under restrictions. Fox farms corn and soybeans along with some wheat and cotton near Pratt in south central Kansas the drought started last year.

“Everybody over-pumped (their water),” Fox said. “Everybody tried to finish their crops that they had in their ground. The state is monitoring us and yes we are having to cut back this year.”

Lane Letourneau, who manages water appropriations for the Kansas Division of Water Resources, said temporary restrictions are possible for farmers like Fox. But many people are avoiding penalties by signing up for new multi-year irrigation accounts which allow farmers to pump extra water in 2012, as long as they conserve water later. Letourneau said the goal is to balance losses from sources like the Ogallala Aquifer.

“We are seeing huge declines (in the aquifer),” Letourneau said. “Like right south of Garden City, we saw 10 feet of decline on average just in one year. We’ve seen 28 feet over the last three years. So there are some areas that are very concerning to us.”

Normal rain and a snowy winter in the Rockies could quickly refill diminished rivers and reservoirs in Nebraska and Kansas. But underground aquifers are slower to respond. When the drought ends it could take months for water to filter back down through layers of dry dirt and sand. Jason Lambrecht, who is following the drought’s impact water levels in Nebraskafor the U.S. Geological Survey, described it like a stack of sponges.

“Pour a glass of water on a stack of sponges, how long will it take for that water to reach the bottom sponge, if it reaches there at all,” he said.

Lambrecht said history shows droughts are usually more than a one-year disaster. Irrigation kept many farmers in Nebraska and Kansas from feeling the worst of it in 2012, but to keep their edge in dry years ahead some farmers may need to give their water sources some time off.



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