After decades of draining, some MN farmers look to put water back

Like most Red River Valley farmers, Gerry Zimmerman has spent lots of time and money getting water off his fields. Now, though, he's working to pump some of it back.

While too much water remains an enemy of the valley's farmers, Zimmerman says it was time to start thinking differently. He designed a system to pump water from a drainage ditch near his farm back into his field through the underground drain tile when crops need extra water. He got a permit from the state Department of Natural Resources and the local watershed board.

"Traditionally, in the valley here where we're at, we always get hurt by too much water," he said as he sat in his farm office. "I decided we wanted to be able to pour water back into the tile as well as drain."

Zimmerman is one of only a very few farmers testing this idea. Subirrigation has been used in other parts of the country, but there's little research in the Upper Midwest.

The experiment could open the door to a better way to irrigate fields and manage water in a changing climate. Zimmerman also acknowledges that if the idea catches fire, conflicts are sure to arise.

"If somebody upstream from us decides they want to try to do the same thing that I'm doing, they could start in pumping water," he said. "Eastern water law says everybody owns the water, and then you'd end up going to court I guess, if you're stubborn enough." Zimmerman said with a laugh.

He's teamed up with researchers at North Dakota State University in Fargo. They monitor the project to see how subirrigated fields compare to fields with no irrigation. He pumps water in July and August when thirsty crops like corn, sugarbeets and soybeans are in peak growth.

"Does subirrigation work? It definitely works. You going to get the same results every year? No, because the weather and how much water you get from mother nature is always different," Zimmerman said.

Using drainage tile for irrigation requires a slightly different approach. The tile must be installed closer together, and that can increase the installation costs. There must also be extra pipes and valves to direct water back underground.

Zimmerman says he's learning and making mistakes each year. But he's sold on subirrigation. In 2012, a very dry summer, he says the extra underground water increased corn yield by about 30 percent.

But there was a problem. The drainage ditch where he gets water to irrigate the crop nearly ran dry.

Jeff Strock, a University of Minnesota soil scientist based in southwest Minnesota, is working on a solution to that problem. His idea uses drain tile to help smooth out the increasing extremes in precipitation caused by a changing climate.

"We may get wetter in the fall and in the winter, but during the critical period when our typical crops, corn and soybeans, that we grow now are growing, we're going to become drier," he said. "That will really challenge farmers."

The plan is to collect the excess water that runs off of fields in the fall or spring and store it in small ponds on the farm.

"And then using that water to put back into the same fields where it came from during the growing season, that May through August period when the crop is actively taking up water," said Strock, who's part of a multi-state research project funded by the United States Department of Agriculture to improve water management.

Other researchers are studying ways to store water in the underground drain tile and use saturated buffers to slow runoff and improve water quality.

Strock says subirrigation is more efficient than overhead sprinklers because water isn't lost to evaporation. In areas with heavy soils, the water will stay in the soil long enough to give crops a critical boost.

"If we were to think out into the future, and I don't know how far that is, my vision would be that we've got farms that have storage reservoirs or ponds kind of dotting the landscape," he said. Those farms would put the water "back into the same fields where it came from during the growing season."

Strock knows farmers won't be eager to turn farmland into ponds. But he says the ponds won't be large, and most farms have marginal areas that could be used. Each pond might hold 1 to 3 million gallons of water.

Strock says on-farm water storage might also help reduce spring flooding in the Red River and Minnesota River valleys.

A southwest Minnesota farm is a model and will get a new holding pond this summer for irrigation in the 2016 growing season. Strock expects it will take a couple of years of research to develop best practices for farmers.

Subirrigation won't work everywhere. It can't replace overhead sprinklers in very sandy soils. But Strock thinks for a big chunk of the western side of the state, it could be one answer to helping farmers manage an increasingly variable climate.

Remember Gerry Zimmerman's problem with the ditch running dry just when he needed water to irrigate his crops? Strock thinks it might be time to consider using ditches to store irrigation water.

"In Minnesota, there's about 27,000 miles of drainage ditch," he said. "I look at that as 27,000 miles of opportunity." He expects that idea won't get a friendly response because farmers see ditches as a way to get rid of water. But Strock says if climate change creates long, dry summers in Minnesota, farmers and policy makers will be forced to find new ways of doing business.