Subsurface water systems can boost yields, carry nutrients
Nebraska farmer Don Anthony started using subsurface drip irrigation (SDI) in 2006 on sections of his 1,200-acre corn and soybean farm in the Central Platte Valley. He began with a parcel of flat land that had a power line running diagonally through it.
Anthony had always used a center-pivot system, but a 1997 federal agreement affecting his state requires field corners untouched by pivots to be watered as well. Failing to irrigate those areas would result in the loss of their irrigated status, meaning they could never be irrigated again.
Since 2005, Anthony has added 250 to 300 acres of SDI, which delivers water to crop roots through a series of pipes and nozzles normally buried 10" to 14" below the surface. This year, one 80-acre section of corn—irrigated with 15" of water throughout the course of the growing season—yielded 188 bu. per acre.
"My experience in the past seven years with the pivot here versus drip across the road is that I’ll put on about two-thirds to three-fourths the amount of water with drip as I do with pivot and get the same yield," Anthony says.
He’s not alone. The subsurface irrigation method, first adopted in the U.S. for vegetables, fruits and nuts, is supplementing and even replacing center-pivot systems for field crops. Representatives of three of the top SDI businesses—Netafim, the Toro Company and John Deere—say the system is attractive to farmers worldwide because of its potential to save water, boost yields and reduce ferti-lizer runoff.
Netafim is the world’s largest manufacturer of microirrigation equipment, including subsurface drip components. Michael Dowgert, Netafim USA communications director, attributes the increased interest in subsurface irrigation to GPS development.
"Now you are able to find the dripper lines," Dowgert says. Subsurface irrigation has been in use since the 1970s, but its use with GPS started in the late 1990s.
Cotton tops the list of U.S. field crops most often used with subsurface. In the West Texas area, Dowgert says, close to half a million acres receive belowground irrigation. Corn ranks second, and SDI is being explored in states such as Nebraska, around the Ogallala Aquifer, where water scarcity is a key concern.
Just a few years ago, Netafim installed about 400 acres of subsurface systems in alfalfa, Dowgert says. This year, the company expects to install more than 4,000 acres for alfalfa alone.
While alfalfa often is flood-irrigated, using subsurface can remove stress on the plant and result in "fairly significant yield increases," Dowgert says. Farmers can even irrigate the crop while harvesting it.
Interest grows. Hubert Frerich opened Eco-Drip Irrigation in Garden City, Texas, in the early 1980s after successfully irrigating his watermelon and cotton crops with a subsurface system. No high-producing wells existed in the area, so limited access to water made subsurface an efficient alternative, says Craig Hoelscher, who now co-owns the company along with three of Frerich’s children.
"It helps make every drop count," notes Hoelscher, who adds that the system is also used to spoon-feed crops with fertilizer. Eco-Drip has installed as many subsurface acres in the past 10 years as it did in its first 20, totaling 200,000 acres. The company is getting more questions about subsurface systems and seeing a small pickup in demand across the central U.S.
- December 2012