Tale of the Tape: Drip Irrigation Tests in Field Crops

-- Thought Leadership

In the 1800s, settlers staked claim to land in the Texas High Plains in part because of its access to one of the world's largest sources of fresh water. That underground lake—known as the Ogallala Aquifer—stretches beneath eight states, from South Dakota down to Texas, and has helped turn the land it irrigates into some of the world's most agriculturally productive.

But recent studies have shown that this vast resource is being depleted faster than previously thought. Texas' High Plains Underground Water Conservation District reports an 8.8-foot drop in underground water levels over the past decade, with several counties seeing declines of more than 15 feet. And a recent Kansas State University study projects, if irrigation continues at current rates, a 69% depletion in the aquifer by 2060.

So what can be done to conserve those reserves? Many approaches, both new and old, are being researched, but one method of particular interest is subsurface drip irrigation (SDI).

But could drip replace center-pivot irrigation in field crops to improve water conservation and increase yields? That's exactly what Texas researchers and producers set out to determine. Rick Kellison is project manager of the Texas Alliance for Water Conservation (TAWC), a group of farmers, researchers, and state and local agencies working to develop water conservation strategies. In 2012, the TAWC worked with Eddie Teeter, a Lockney, Texas, producer—65 miles north of Lubbock—to test drip irrigation versus LEPA (low-energy precision application) on 240 acres of his property.

Local drip installer Dusty Cornelius worked with Kellison and Teeter to design and install an SDI system from irrigation company Netafim on the 240 acres of flat crop ground. Cornelius ran dripline 12 to 14 inches subsurface on conventional-tilled grain sorghum, cotton and corn, and he spaced the dripline on 40-inch centers.

According to Kellison, the amount of water used in SDI and LEPA was the same. At the trial's conclusion, the corn yield from SDI was slightly higher, but, Kellison says it was only "a half-bushel of a … difference in yield."

However, there are still some producers in the area, as well as elsewhere, who say SDI works for their operation because of its efficient delivery of water where it's needed—roots. Other producers, worry about the cost of installation and maintenance issues, especially when groundwater contains more sand and other solids. 

It's complicated, say those involved in the High Plains study. "There's not cut-and-dried best management practices for any kind of irrigation," Kellison adds of field crop observations. Producers need to match their irrigation to localized conditions, such as soil type and water quality.

"Regardless of technology," he continues, "we're trying to introduce producers to management technologies that help utilize whatever delivery system they have in place."

For more information, including estimated cost of SDI installation v. LEPA and specific advantages of each, visit the full story at http://www.myfarmlife.com/advantage/tale-of-the-tape-drip-irrigation-tests-in-field-crops/