Minnesota Corn Growers Association
Written by Jonathan Eisenthal
Two sections side-by-side in Faribault County are used exclusively for growing corn and soybeans. Both are watersheds that are hilly, and runoff moves quickly and discharges directly into the Blue Earth River. This makes the pair of sections an ideal ‘outdoor laboratory’ to compare and contrast farming techniques aimed at improving water quality.
USDA-ARS Scientist Gary Feyereisen applied to the Minnesota Corn Innovation Grant Program with the idea to create a farmer-driven research project in which producers in the watershed designated CD62 and watershed CD30 decide which new methods to adopt, in order to test their impact. Producers will work with Feyereisen to determine nitrate reduction in the water that runs off these farm fields.
“These producers could implement any and all the potential techniques to improve water quality in the water that is coming off the fields. They have the opportunity to make this a demonstration watershed,” said Feyereisen, who is also working closely with Michele Stindtman, program administrator at Faribault County Soil and Water Conservation District.
Stindtman said, “We are not going to come in here and tell the farmers what we want them to do, but instead, we are going to let them figure it out. Let them talk, and then come up with solutions they want to try. We can provide guidance, but in the end, the idea is for farmers to learn how to do the conservation techniques from other farmers. Peer-to-peer learning is a successful approach over the long term.”
Among the potential test treatments:
1. Management in the field—the careful application of fertilizer in terms of form, rate, timing.
2. The vegetative aspect: cover crops, rotations that add additional cash crops.
3. Structural practices like bioreactors or installed wetlands. Something where the water is treated after it leaves the field.
The project has a head start, in that CD62 has what Feyereisen believes may be the largest bioreactor in the United States. Installed in 2016, it has three chambers. When the first fills to capacity, the overflow begins to fill the second chamber, and when that is full, the third chamber comes into play.
A sophisticated flow-weighted nitrate measuring system, installed at the same time as the bioreactor, takes samples automatically, increasing the frequency of collection when more water is flowing through. They now have three years of data from it.
This project will add the same kind of monitor in CD30. Feyereisen says ideally they would measure the two watersheds simultaneously for one or two years, without management changes, to establish a baseline relationship in flow and water quality. Once that is established, they will be able to show the impact of any new conservation practices that are added to one or the other of the watersheds.