JASON WIEST / For the Lincoln Journal Star | Posted: Friday, February 3, 2006 6:00 pm
Across Nebraska’s summer horizon, metallic arms sweep slowly over acres of green corn. From above, large green circles — like lily pads — dot the Cornhusker state’s Platte River Valley.
Center-pivot irrigation systems, invented in Nebraska, are delivering water to thirsty crops in increasingly efficient ways. And their numbers likely will increase with new technology, federal subsidies and the drought.
The increase could combat Nebraska’s dwindling groundwater levels because pivots waste 50 percent less water than does traditional flood irrigation.
But more center pivots would suck up more water, which could cause further decline in the groundwater supply.
Nebraska already ranks second in the number of irrigated acres, behind California, and Nebraska farmers’ enthusiasm for irrigation shows no sign of declining.
The number of irrigation wells in the Central Platte Natural Resources District shot up by 797 in the past year, according to the state Department of Natural Resources. This dwarfs previous annual increases, which never broke 300. The Central Platte now has 20,555 irrigation wells — amounting to more than 20 percent of the wells in the entire state.
But on Dec. 6, the district’s board of directors imposed a moratorium on new irrigation wells. Its earlier threat of a moratorium might have been what prompted the surge in drilling, according to Dave Thom, president of Hastings-based T&L Irrigation, one of the world’s leading pivot builders.
“You could have good water under your land, but if a stay comes in place and you can’t drill a well there, the land value drops in half,” Thom said, prior to the board’s decision.
Farmers have had help in making use of newly drilled wells.
A U.S. Department of Agriculture program encourages farmers to use center pivots. Since 2002, about 4,500 Nebraska farmers have used funding from the program to buy 1,055 center pivots on about 146,000 acres, said USDA spokesman Pat McGrane.
In 2005, the program granted $5.5 million dollars to Nebraska farmers — what McGrane described as a worthwhile investment because pivots save water.
Thom said manufacturers are continually improving pivots’ water-saving capabilities.
Recent advances allow farmers to control pivots from their home offices via computer or cell phone. If it starts to rain, farmers can dial up their pivots to shut them off instead of driving out to do it manually.
And the amount of water they apply continues to decrease because of other improvements.
Newer pivots use less water pressure, which saves energy and also creates larger droplets of water. Larger droplets don’t evaporate as easily as mist-like droplets.
But Chad Smith, director of the Nebraska field office for American Rivers, said even though pivots are efficient, they’re not going to solve Nebraska’s water problems.
“You can’t go and put thousands and thousands of center pivots in place — you’d be losing whatever efficiency gains you’re getting from technology by using too much of it.”
Thom estimates 50,000 pivots are in use in Nebraska.
Smith said center pivots opened the door to groundwater depletion by giving irrigators a more efficient way to move groundwater to crops.
During the drought of the past five years, groundwater levels have declined by an average of 5.7 feet across the Central Platte NRD, which includes parts of 11 counties between Columbus and Gothenburg. That decline, combined with uncertainty about how a new state law will affect irrigation, led to the moratorium on new wells.
Jason Wiest is a news-editorial major at the University of Nebraska-Lincoln College of Journalism and Mass Communications and a student in the college’s science-writing class. Reach him at jasonwiest@excite.com.