Smart drainage era beginning?
The days of tile lines running open 24/7, every day, all year long will one day be a thing of the past. That’s the prediction of Charlie Schafer, a 35-year veteran of the drainage and, more recently, drainage water management. He is president of Agri Drain, a company located at Adair in southwest Iowa.
“It would certainly be unfortunate if we weren’t entering a new era of smart water management,” Schafer says. “We have the technology, the need and the market. Our agricultural landscape is going to be highly managed over the next 100 years, and there’s no doubt in my mind we’ll have a water management system that turns drainage on and off as part of it.”
That management of the underground water table will result in better use of nutrients, to maximize yields and minimize loss of fertilizer to downstream waters.
“I figure if we can drive tractors by satellite and open locked car doors remotely from anyplace in the country, we can develop smart drainage systems. Just like we turn lights on and off to save energy, we need to turn tile drainage on and off to keep water in the soil profile for when we need it. I call it smart drainage. Some call it conservation drainage, and to [the Natural Resources Conservation Service], it’s drainage water management.”
By whatever name, the concept is to use water level control structures within tile lines to raise and lower the water table. Most often the structures are used to close the drains in the fall after harvest, open them in the spring before field operations, close them again after planting to varying heights to make water available to crops as needed, and then close them again before fall field operations.
Water quality, yield benefits
Two primary factors are driving the move toward smart drainage, Schafer says. “I remember 35 years ago we’d drink from tile lines,” he says. “Now we know they carry excess nitrogen and some phosphorus. So water quality downstream is a big issue. Secondly, we’re told that with today’s hybrids, the limitation to reaching 350-bushel-an-acre corn yields is the availability of water. We can address both issues with smart drainage.”
For 150 years, farmers have used tile drainage to improve yields in wet years. Smart drainage systems still do that, but also can hold water in the profile to make water available in dry years. In North Carolina, studies have shown yield increases average about 5% over free-flowing drainage systems, with some studies showing up to 10% increases. Midwest research isn’t yet conclusive.
Redwood County, Minn., farmer Brian Hicks is the first farmer in Minnesota to have a controlled drainage research project on-site, and he’s seen enough of smart drainage to be sold on it. Two years of side-by-side research showed a 91% reduction in nitrate and a 75% reduction in phosphorus leaving the field through tile.
“We’re very early in the research and don’t have verifiable yield data, but I know we are keeping nitrogen in the soil profile longer, and it’s money in the bank to hold onto every pound of nitrogen you can with today’s fertilizer costs,” he says.
Research projects in Corn Belt states show from 30% to 50% nitrate reductions in water leaving the field with management systems.
Schafer joined government, research and industry folks about 10 years ago on the Ag Drainage Management Task Force, at a time lively discussions were taking place on hypoxia in the Gulf of Mexico. “We’ve worked with the Agricultural Research Service and others to take a closer look at how water moves through the soil and what it takes with it,” Schafer says.
“To us, it’s simple. Turn off the drainage system when you don’t need the soil to be drained. For instance, it’s been common knowledge that half the water that leaves a tiled field is from winter flow. If you keep that water in the soil profile during the winter, you keep the nitrogen and phosphorus with it,” he says.
Cumulatively, the benefits from keeping nutrients in the water table with smart drainage could be staggering. In five Corn Belt states, about 8 million acres of very flat, poorly drained soils are most suited to the practice. “If smart drainage were used on all that land, the farm and downstream benefits would total up to $1.4 billion a year, and reduce nitrate loads in downstream water by 128 million pounds,” Schafer says.
Costs of installing water level control structures and water gates (see story on Page 50) in smart drainage systems vary, but can be as much as $100 an acre and more, depending on slope of the land. Schafer believes the practice deserves stronger consideration for public cost-sharing, since the practice holds such promise for reducing public costs like denitrification of municipal water supplies.
“There’s so much offsite benefit to this practice. We’ve seen waterworks invest or cost-share in surface water quality practices in the upstream watershed, but there’s even more potential if they couple managed drainage with surface water quality practices,” Schafer says.
“Smart drainage complements surface practices like conservation buffers very well. It’s much more cost-effective than taking land out of production, for instance, and it’s part of a solution to feed a hungry world while being environmentally responsible.”
Only a few thousand acres have smart drainage systems in place. Most farmers hold to the belief that it’s a good thing to drain as much water as possible from the field as fast as possible. But that could be changing. Systems that stockpile water, and nitrogen, in the soil for use when the crop needs it could make more sense.
Betts writes from Johnston.
This article published in the December, 2011 edition of WALLACES FARMER.