Where drip irrigation fits in
By Chester Peterson Jr.
There are three main types of irrigation in the country: gravity, center pivot, and subsurface drip irrigation (SDI). Roger Brining has experience with all three on his Great Bend, Kansas, and Alamosa, Colorado, farms.
His remarks about gravity irrigation are unkind at best. “I hated it,” Brining says. “In fact, we rented out all the flood-irrigated land because it wasn’t cost effective for us. As for center pivots, I put one on any field where I have the opportunity to run a full circle and can water all of its permitted acres.”
Mixed Results With SDI
“So far, on smaller fields, I’m not seeing dramatically different yields for my SDI that’s 16 inches deep on 40-inch centers than I’m seeing for my pivots,” he notes. “The SDI uses 25% less water, though.”
Brining points out that, depending on field size, SDI installation costs can range from $850 an acre (when the pipelines are installed at 60-inch centers) to $1,500 an acre (on 40-inch centers) with automatic controls. Although there has been government cost-share available of late to lessen that pain.
“With SDI, I have more precise watering micromanaging it. For instance,” he says, “I can set the programs early and late in the season to run a minimal .18 inch to .20 inch every two or three days. Then in peak season, when usage picks up, I’ll run every single day with the amount the crop requires, plus fertilizer as needed.”
Brining’s experience indicates that SDI requires half the water of gravity irrigation, which represents a dramatic savings. The only loss with SDI is the water used to flush filters.
Another advantage to SDI is its ability to capture a heavy rain without runoff, since the top 8 to 12 inches of the field remain dry and sop up rainfall.
SDI has its shortcomings, he points out. For example, a center pivot can be utilized to water up a newly planted crop, which SDI is incapable of doing.