Field Day connects the dots between cover crops, tillage and trout

NORTHFIELD, Minn. (KEYC) — A study discussed at the field day in Northfield hopes to conserve natural resources.

The field day looked at the addition of cover crops and different tilling methods to conserve soil and reduce erosion and how current practices may be affecting water quality and the species that call the water home.

“With our Rice Creek system, we’re actually seeing that those fields that are cover cropped at a given point in time during the growing season seem to have less nitrate in their agricultural drainage line admitted to Rice Creek compared to fields that were not cover cropped,” said Paul Jackson, professor of chemistry and environmental studies at St. Olaf College.

Professor Paul Jackson along with another St. Olaf professor and member of the Cannon River Watershed Partnership are conducting a three-year experiment studying the use of cover crops to manage agricultural drainage.

“And that difference looks to be quite substantial, sometimes the factor of two to three times, so we’re talking values that are well above say, a drinking water threshold of nitrate in river systems,” said Jackson.

Participants in the study are interseeding cover crops when the commodity crop reaches a specific maturity level so the cover crops will continue to grow after harvest.

“Pulling up more nutrients and holding the soil in place so that as the ground freezes everything is held in stasis through the beginning of the next growing season when you actually strip till or no till through those and you start the growing season back over,” said Jackson.

Reducing runoff is beneficial to multiple species, including the decreasing population of brook Trout in Rice Creek as tiling, vegetation changes, increased flood events and denuded soils threatens their ecosystem.

“Anything we can do on the watershed to help keep the water on landscape or in the watershed and also any kind of cover project we do, like the cover cropping we talked about this morning, helps reduce sedimentation which can impact these brook trout,” Waterville Area Fisheries Supervisor Craig Soupir said.

“Both farmers and a variety of agricultural professionals and environmental professionals can come in work together to make positive influences and we’ll actually see some of the nutrient issues that we’re experiencing now, hopefully, decreased within the next decade,” said Jackson.

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