As with most innovations in farming, the bottom line in determining whether or not to adopt is cost, and subsurface drip irrigation has proven no different.

As irrigated acres continue to increase in the Southeast, growers are looking for the most efficient method, and they want to know how the cost of drip irrigation compares to the tried-and-true center pivot system.

Answering this question is the focus of research begun in 2010 by the University of Georgia.

“About 40 percent of Georgia’s cotton acreage is irrigated, and most of that is entirely under center pivots, but we have increasing interest in subsurface drip irrigation,” says Don Shurley, UGA Extension economist.

“Producers have questions about cost comparisons with center pivot systems, and we’ll eventually get answers to those questions.”

More specifically, says Shurley, growers want do know where and how does drip irrigation fit into their operations. There are many factors to consider, including crop rotations, row spacing and tillage, he adds.

For example, in southwest Georgia, most cotton and peanuts are on 36-inch rows and corn will be on 30-inch rows or 36-inch. If you go to the east part of Georgia, a lot of the row crops are still on 38-inch rows.

“Depending on your crops and your crop rotations, where do you set your drip tape spacings? How does it match up with your crop and your rotations?”

Reliability of application is another factor, he says. “When you turn on a pivot, after a few minutes, everything is wet. When you have drip tape, you’re not sure the water is getting to the crop. I know this sounds silly, but farmers need to know that water is getting to where it needs to be, especially if you’ve got the tape set up every other row. If you’ve got 36-inch rows, you might have tape set every 6 feet.”

There also are implications for tillage, says Shurley.

“For our research, we have the drip tape set at 2 inches and then at 12 inches. In talking with irrigation dealers and producers, 2 inches is probably too shallow and 12 inches is probably too deep.