Climbing nitrate concentrations in the city of Sioux Center’s drinking water supply posed a potential problem for both the city and the Schuiteman family that farms land around the city wells.
To find a solution the city partnered with Dordt College in Sioux Center and third-generation farmer Matt Schuiteman (pictured above - right) to look at five different crop rotations that could be both economically viable and reduce nitrates in the water supply.
“If that land has to come out of production, that’s not good for anybody,” said Schuiteman, who farms in partnership with his parents. “Anything we can do to keep that nitrogen out of the water is the way to go.”
Dordt researchers are still analyzing the results of the four-year study, which wrapped up last fall, but Schuiteman said some rotations were obviously better than others despite wild swings in weather that included severe drought in 2012 and an extremely wet spring in 2013.
“We didn’t really have a normal year, so in terms of how the crops did it’s hard to get an accurate judgment,” he said. “As far as the nitrates, we did see some really interesting things regarding how the nitrates move in the soil.”
For example, water sampling showed nitrate levels in one of the wells on Schuiteman’s farm had been running between 5 and 8 parts per million (ppm) for about 18 months. The maximum allowable level of nitrates in drinking water is 10 ppm.
After alfalfa was planted near the well in March 2012, nitrate concentrations dropped below 3 ppm within three months. The levels have remained relatively stable since then, even during last spring’s heavy rainfall.
“Alfalfa is surprisingly effective at pulling nitrates into the top part of the soil,” said Schuiteman. “The wheat and oat rotations, we didn’t see as much. The small grains didn’t reach down and pull it up.”
As a result, Schuiteman is planning to alter his rotation on almost 100 acres around the wells to include two years of alfalfa, followed by two years of corn. He figures he’ll only have to apply a small amount of starter fertilizer to corn the first year after alfalfa, reducing nitrogen applications by about two-thirds compared to continuous corn. “What’s going to be really nice, all those wells are tested quarterly or monthly for nitrates, so we can keep an eye on the trend,” Schuiteman said.
Plentiful livestock numbers in northwest Iowa provide a market for the alfalfa, but not every part of the state has such high demand for hay, said Schuiteman, who has a cow-calf herd and raises hogs farrow-to-finish.
“The alfalfa market has been good for the past couple of years, but there’s a limited market,” he said. “For a sensitive area like this one, this is a pretty good solution but it might not work everywhere.”
Biological and economical
Considering the surrounding landscape is important in finding workable solutions to environmental challenges, said Rob DeHaan (pictured above - left), an environmental studies professor who led Dordt College’s participation in the study.
“We’re trying to figure out what can be done biologically that also works economically, and works sociologically,” he said. “Farmers have to have the equipment and the ability to do these crop rotations.”
For the city of Sioux Center, Schuiteman’s efforts mean the city doesn’t have to blend as much water from its lower-quality deep wells or spend money on costly nitrate removal systems to meet the drinking water standard for nitrates. It also provides the growing city with a road map as it looks for new water sources.
Schuiteman noted that the city recently drilled a test well on a piece of land that has been in the Conservation Reserve Program (CRP) for more than a decade yet still tested extremely high in nitrates, proving that idling land isn’t necessarily the best way to improve water quality. At the same time, four years of testing shows a well located in a pasture where Schuiteman’s cattle graze continuously has very low nitrate levels.
“It’s important that the land is able to stay productive. When we started, the only play in the book was CRP.
Economically, CRP doesn’t work,” said Schuiteman, whose wife, Minde, is expecting the couple’s seventh child in April.
Strip till and cover crops
Schuiteman also employs a number of other conservation strategies, including cover crops and strip tillage, to keep soil and nutrients in place between growing seasons.
He first planted cover crops in 2006, long before they became a mainstream conservation strategy. He’s tweaked his crop rotation over the years, and now primarily grows continuous corn with a rye cover crop between growing seasons. In addition to providing needed forage for his cattle herd, the cover crop/strip till system has led to improved corn yields.
“It’s really been a dynamite system for corn and livestock,” said Schuiteman, who uses a Soil Warrior strip till rig. “We plant the corn right into the rye, and then come back to spray the rye to kill (the cover crop).”
He hasn’t seen negative yield effects of rye competing with corn, which has been identified in other some studies if the cover crop isn’t killed properly.
“Our yields have been fantastic. It beat the chisel plow by 10 bushels per acre,” Schuiteman said.