Wheatgrass helping to keep Chatfield’s water clean

GRETCHEN MENSINK LOVEJOY/CHATFIELD NEWS Chatfield maintenance supervisor Brian Burkholder stands in a harvested plot of Kernza intermediate wheatgrass. The field has lysimeters, or gauges to measure how much nitrate has been removed from the groundwater that eventually becomes drinking water. Kernza also slows erosion of fields because it has deep roots.
Gretchen Mensink Lovejoy

Pilot project shows benefits of unique approach to reducing nitrates in drinking water


City officials are finding that perennial crop cover wheatgrass may just be the way to improve water quality in Chatfield.

“We have nitrate levels of 0.4 to 0, and it’s showing that the roots are using up the nitrates, doing their job.  We’ve got a ways to go yet, but we’re gaining, as far as I can tell.  It’s showing that the Kernza is using nitrates the way it should be,” stated Chatfield city maintenance supervisor Brian Burkholder, telling about the farming he, a non-farmer, has witnessed and done as part of his job.

Intermediate wheatgrass, also known by the trademarked name Kernza and developed by the University of Minnesota and the Land Institute in Kansas, has made a difference in the city’s drinking water since it was planted on a total of 11 acres – three of those belonging to the city and the other eight belonging to local farmer Paul Novotny – two years ago on land near the city’s drinking water wells. The pilot project planting was part of Chatfield’s wellhead protection plan for its drinking water service management areas (DWSMA), because the plant is thirsty for water running off hillsides and is able to extract nitrates from the runoff, cleaning aquifers from which the city’s drinking water is drawn.

“The first 10 years, we didn’t do anything to try to control nitrates, but the mitigation plan states that the highest nitrate level is 5. We were at 4.4, and we don’t want it to get to 5.  Our DWSMA has been expanded, and we’ve updated our drinking water plan.  The whole goal is to protect our drinking water and reduce nitrates,” Burkholder said.

Because Kernza is a wheatgrass, it has the deep, curtain-like root system so characteristic of perennials, according to Brian DeVore of the Land Stewardship Project (LSP). In fact, University of Minnesota researchers say Kernza roots often extend deeper than they are able to dig with a shovel, he wrote in a recent article in an LSP newsletter. 

“That’s good news when it comes to water quality, since having a living root system present in a farm 365 days a year helps build the soil’s ability to manage and store water runoff while soaking up contaminates,” he wrote. “Kernza’s knack for taking up nitrates is of particular interest in farm states like Minnesota, where nitrogen fertilizer used in the production of crops like corn has become a major pollutant in many rural communities.” 

Since 1994, the Minnesota Department of Health has found 51 community wells drawing water with nitrate levels near or above federal safety standards.  Some communities have had to install water treatment systems, while others have simply drilled new wells in an attempt to bypass contaminated aquifers.  There are also many private wells on farms and other rural properties that have been contaminated with high levels of nitrates, making the water unsafe for drinking, particularly for infants. All of the options for procuring safe drinking water in an area where nitrate contamination is prevalent are expensive.

An alternative approach is to prevent the contamination from happening in the first place, and that’s by making changes on the landscape, according to Dr. Jake Jungers, a perennial cropping systems ecologist who is researching Kernza at the University of Minnesota.  Jungers, along with other researchers at the U of M and the Kansas-based Land Institute, recently conducted a study where they compared the amount of nitrates escaping fields planted to three different plant systems: corn, switchgrass and Kernza. 

According to the study, which was published earlier this year in the journal Agriculture, Ecosystems & Environment, the amount of nitrate leaching in the Kernza field was two orders of magnitude lower than it was in corn; it was one order of magnitude lower when compared to switch grass, which is also a perennial.

During a July field day at the Carmen and Sally Fernholz farm in Madison, Minn., Jungers displayed a chart showing that during the entire growing season, nitrate leaching under a Kernza field was well below the federal drinking water standard.  The ability of switchgrass to keep nitrates below the standard kicked in by July, while corn produced unsafe levels of leaked nitrates all the way until September.

DeVore’s article noted that such results have caught the attention of municipalities.  His article cited Chatfield’s pilot program in southeastern Minnesota, where karst geology makes groundwater particularly vulnerable to contamination, with hope that it will provide more communities a chance to utilize the perennial grain as a water quality protector.  

But just how does Burkholder know that the remaining 10 acres – three belonging to the city on the corner of Olmsted County Road 10 and 155th on the way to Dover, seven belonging to local farmer Paul Novotny, and the single acre on Amco Drive that will become ground for a housing subdivision – have done what the University of Minnesota and the Land Institute promised? 

Simple. It’s lysimeters, or measuring units that are stuck into the ground at occasional distances throughout the planted acres to gauge how well the intermediate wheatgrass has absorbed nitrates and freed the groundwater of hazards to humans, that do that work.  Burkholder walked past two in the plot on County 10 recently, the only markers left to show that this year’s crop had been there.  While he and city water supervisor Ryan Priebe may not have all the notes on the lysimeters’ operation, they appreciate that progress is being made. 

Chatfield received the “very small” seeds from the University of Minnesota and planted them three Septembers ago, attempting to find and borrow the right equipment to get them into the ground so that they’d be established for the coming spring, Burkholder noted.  He cited that in the first season, they might have planted them too close together, but there’s trial and error in farming, especially when he admitted to not being a farmer.  That error has certainly been overcome by the crop’s success in growth and use as a water filter for nitrates.

Larger communities have taken notice of Chatfield’s willingness to give it a try. In mid-September, the Clean Water Council from Minneapolis checked out the plot by the high school, took a site tour, and listened to speakers. 

“It was nice that they came down here,” Burkholder said.

At the end of the first season, the grain was harvested and sold, as it was this August when what hadn’t been blown over by high winds and pushed down by heavy rains was taken from the ground, combined and threshed, then hauled to Madison, Minn., where it was washed in a facility likely alongside the Kernza crop planted by the Fernholzes, as Burkholder stated that that’s the nearest place to have intermediate wheatgrass washed and dried. 

“This year, we harvested a week late due to rainy weather, and some of the grains fell off so we didn’t harvest the same quantity.  But the university pays us for harvesting it, and the square bales are purchased by a local farmer for feed.  It’s high in protein, so the cows are eating it, or they use it to mix in feed, and you can graze the plots after it’s been harvested.  The grain itself, they’re still trying to come up with uses for it, like beer or cereal, and General Mills is interested in it.  There’s food being made out of it, like bars and beer,” he said.

Chatfield’s plants are now older perennial crops because Kernza lasts up to five years, but right now, the city is awaiting an opportunity “to buy back some of our own grain to promote it to local breweries, because once we sell it, it’s hard to get back.” 

Right now, there are only three plots in Minnesota. Chatfield officials got the idea from the University of Minnesota when they were at a Minnesota Rural Water Association (MRWA) conference in St. Cloud. 

“The university is coming out with new grains to plant now,” Burkholder said. “We have maybe one or two years left on these plants, but the university is still working on uses.”