Lysimeters installed to help monitor nitrate levels in city’s Kernza fields

Representatives of the city of Chatfield, the University of Minnesota and Minnesota Rural Water Association place lysimeters in the intermediate wheatgrass field the city planted just off County 10. GRETCHEN MENSINK LOVEJOY/CHATFIELD NEWS
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Chatfield’s percolating soil is extracting from the intermediate.

“Lysimeter: a device for measuring the percolation of water through soils and for determining the soluble constituents removed in the drainage,” defined the Merriam-Webster Dictionary.

This also explains exactly what it is the University of Minnesota and the Minnesota Rural Water Association (MRWA) installed on the intermediate wheatgrass-covered hillside just off County Road 10 northeast of Chatfield in late May.

The intermediate wheatgrass planted there last August, a new perennial grain that is being developed in partnership between the University of Minnesota and The Land Institute, is called by its trademark name, “Kernza.”

According to Jacob Jungers, of the University of Minnesota, “Intermediate wheatgrass was introduced to the U.S. as a forage crop and was selected as a candidate for development into a perennial grain crop in the 1980s. The Land Institute in Salina, Kansas, has been breeding intermediate wheatgrass for high grain yield and large seed size for about 15 years. The Land Institute partnered with the University of Minnesota in 2011 to help with the breeding efforts and to research the agronomics on environmental impacts of this new crop.”

Jungers also explained that a three-year study conducted by the University of Minnesota and The Land Institute found that nitrate levels were 60 times lower in the soil water beneath Kernza, compared to corn, in the spring which is evidence that Kernza can reduce nitrate leaching to groundwater when compared to annual crops.

“There is growing demand for this high-value crop which can also provide numerous environmental crops. We aim to measure reductions in nitrate leaching with this new project between the University of Minnesota and the city of Chatfield,” he added.

Essentially, Jungers referred to the three-acre plot owned by the city of Chatfield at the intersection of Olmsted County Road 10 and 155th Avenue Southeast, on the way to Dover, where the city has agreed to test how well Kernza can mitigate nitrates that could leach into the drinking water system as part of the city’s wellhead protection plan.

He elaborated, “Intermediate wheatgrass naturally has deep, dense root systems which provide many environmental benefits such as carbon sequestration and nutrient retention. The deep roots and associated environmental benefits are reasons for developing perennial crops.”

Jungers also explained that intermediate wheatgrass also has large seeds, which is why it was selected for development into a perennial grain crop. It requires less nitrogen fertilizer because of the deep root system that can access soil nitrogen where annual crops cannot. Also, it is low-input in that it doesn’t require annual reseeding.

“That means the grower does not need to till the land annually, either” he said. “After the first year, intermediate wheatgrass is very competitive against weeds, and it is more efficient at using at using any nitrogen fertilizer it receives compared to annual crops…therefore less nitrogen can leach to the groundwater in the intermediate wheatgrass system.”

Jungers had even more positive attributes to list for the no-till, drilled-in grain. “Annual crops leave the ground bare in the fall, winter and spring months. This allows for soil to erode via wind and surface runoff,” he said. Sediment and phosphorus from surface erosion can run off into lakes, rivers and streams, therefore polluting those water sources. As a perennial, intermediate wheatgrass provides ground cover throughout the year, therefore preventing soil erosion and protecting surface water quality.”

Chatfield’s city maintenance supervisor, Brian Burkholder, and water supervisor, Ryan Priebe, brought the grass’s benefits to the city’s attention after attending a water conference last year. Also, because the city owns the tillable property just off the county road, it was an opportunity for a partnership to be formed between the city, the University of Minnesota and the MRWA to test just how beneficial planting Kernza could be for drinking water flowing or percolating through the soil.

City Clerk Joel Young commented last year at the Kernza’s planting, “Brian and Ryan were knowledgeable about the fact that the city owns some tillable property, and they are always on the lookout to find ways to protect the city’s drinking water. If this grain can become successful, and if the benefits result in more clean, safe drinking water, we want to do our part to advance that effort.”

Burkholder stated, “The U and Rural Water were looking for a wellhead city that would be interested in doing a test plot for their study in hopes to educate our drinking water system maintenance area (DWSMA) landowners on other crop options. Our plan entails education to landowners on land management practices to reduce nitrate in our drinking water. We have not made much progress in the last ten years. In the last year, the Minnesota Department of Agriculture and Soil and Water are starting to make efforts in this area...this is an action item in our wellhead plan to reduce nitrate levels in our drinking water, and it will hopefully reduce nitrate levels in our aquifers here and downstream. I believe this is a huge step in the right direction.”

Last fall, Jungers commented that the question of whether intermediate wheatgrass has to be planted in a specific place to be beneficial to the watershed was one that had yet to be answered, but at that time, the U of M had proposals in the Legislative Citizen Commission for Minnesota Resources (LCCMR) to fund water quality monitoring beneath the Kernza planting in Chatfield and two other regions of Minnesota. He added that the university’s researchers planned to compare how the new crop performed across different watersheds with different hydrology, geology, soil types and growing conditions.

That’s where the lysimeters come in.

Burkholder cited that the MRWA and U of M had originally planned to install them as part of the planting. “They planned to install these all along, ever since we scheduled the Kernza planting. It is a way to monitor nitrate levels in the soil,” he said. “Ryan and I helped with the installation of eight lysimeters…we haven’t noticed any improvement in the water quality since the Kernza was planted, but that’s why they are installing the probes to help study nitrate levels. Jacob Junger from the U of M will monitor them, and the U will use it for future Kernza projects.”

The more the MRWA and the U of M can learn about Kernza’s effects on water systems, the better, and Burkholder has high hopes for the wheatgrass and lysimeters’ findings as well.

“We are using the plot to study the nitrate level in the Kernza plots and hoping that Kernza will be a future crop for other landowners in the DWSMA, because Kernza is a perennial that uses no nitrates, with a long root system that uses up nitrates. It’s exciting working towards improving our water quality in our DWSMA,” Burkholder concluded.