By Lance Nixon
On land high above the Missouri River, pork producer and produce farmer Mark Rilling used to go to work each summer with 40-foot lengths of irrigation pipe, connecting it stick by stick to get water to his sweet corn, melons and other crops — and, like it or not, to weed seeds on the surface as well.
Not anymore. Thanks to a state-of-the-art subsurface irrigation system, there’s not a length of pipe showing, not many weeds, and not even a wet spot on the soil surface. But the watermelons, peppers, sweet corn and muskmelons are thriving. Yields of high-quality, marketable produce have increased significantly since disease and rot caused by wet soil have been eliminated.
Rilling hired Fort Pierre, S.D.-based Morris Inc. to install the system in 2015 and 2016 on 10 acres of a 14-acre field.
“They come in with a machine that looks like a subsoiler with big shanks on it,” says Rilling. “They load the [irrigation] tape on it. They lay it in the ground 40 inches apart and 12 to 15 inches deep. The tape has an emitter every 2 feet.”
There’s hardware aboveground to allow Rilling to control how much water those emitters put out.
“The plants are never stressed,” Rilling says. And water doesn’t go to waste. “We’re not spraying water around in the air and letting it evaporate. It’s right where the action is — at the roots.”
Because the top of the ground stays dry, Rilling says he has fewer disease and weed problems than with surface irrigation.
Steve Ludemann, ag irrigation supervisor for Morris Inc., says producers can place the water-emitting tapes at intervals of 30, 40 or 60 inches, depending on what they’re growing. At one end of the field is the feed line, and at the other is a flush line, with the drip tapes in between. Producers can use “pressure-compensating tape” that allows the water to come out evenly when going up and down hills. It’s important to use filtered water to prevent clogging of the emitters and drip tape, Ludemann says.
The tape is usually plowed 14 to 18 inches in depth. Here in the Dakotas, Ludemann says he’s seen producers use subsurface irrigation for both corn and soybeans in fields of up to 300 acres.
The cost is less for parcels of 40 acres or larger — from $1,700 to $2,200 an acre to install. Small parcels can cost more, depending on size and the producer’s needs.
Ludemann says subsurface irrigation is already more common in some areas of the United States. He and Rilling expect it to become more popular in the Dakotas, too, as producers try to make the best use of water.
“This is the future of farming right here,” Rilling says.
Nixon writes from Pierre, S.D.