Neal Corey can bale alfalfa and irrigate the field at the same time.

This McCook, NE, semi-retired hay grower installed subsurface drip irrigation on an irregularly shaped 44-acre alfalfa field. The field surface stays dry while the irrigation system delivers water 18" deep.

“The alfalfa roots grow to reach the water source and the plants thrive,” says Corey, who sells hay to local buyers. He gets 6½-7 tons an acre from four cuttings off the field.

The system, also dubbed T-Tape (brand name), trickle or subsurface seep irrigation, uses 25-50% less water than conventional irrigation. That's because there's no evaporation or runoff, says Ben Hardin, an NRCS irrigation specialist in McCook.

“Subsurface drip irrigation is a very viable option for alfalfa growers if you can keep the mice and gophers under control,” Hardin says.

A die-hard irrigation enthusiast, Corey was so pleased with his system that he formed his own irrigation company a few years ago. Since then, he has installed systems on over 700 acres for 18 area farmers.

“I'm not trying to replace surface-type systems, but I think there's a real need for subsurface drip irrigation in some situations,” says Corey.

For example, it works great for small, odd-shaped fields where a pivot or wheel line can't be used. It can also be used in conjunction with pivot systems, watering field corners that pivots miss.

He installed a system for one local corn grower on a 17-acre triangular area between two pivots. The grower applied water at 16.8"/acre with the pivot and 10.4"/acre with the subsurface system. The result? Comparable yields between the two systems.

Another advantage: “A 50-gpm well can water 10 acres with a subsurface drip system, but you can't utilize another type of irrigation with a well that small.”

Subsurface irrigation is expensive to install. Drip tape materials cost $500-550/acre. Corey charges $200/acre for installation, which is a painstaking process.

“By the time I get the well sized, water samples taken and tape ripped in, it takes me about 25 hours to install one acre of drip irrigation.”

To install his own system, Corey dug 36"-deep trenches spaced 5' apart, using a toolbar-mounted soil ripper. In the center of each trench, he placed a 4"-diameter main line and then laid laterals at 5' intervals. Underground, the 15-mil-thick plastic drip tape can last up to 20 years if properly maintained.

A filter, equipped with a fine mesh screen and mounted on the pump, keeps sand, gravel and other particles from clogging the tape and emitters. The filter should be rinsed regularly with water, says Corey. To keep the water lines clean and bacteria-free, he flushes a chlorine solution through them twice a year.

Gophers must be controlled because they like to chew holes in the water lines. Corey makes regular inspections and uses baits and traps. If leaks develop, small puddles are visible on the soil surface.

One thing the system doesn't do is water within the root zone of seedlings. That means Corey has to depend on rain for emergence. So, as enthusiastic as he is about it, he's taking a cautious approach.

“We're still finding things out about this type of irrigation. It's a definite work in progress.”

For more information, contact Corey at 308-345-1416 or ncorey@ocsmccook.com.