September 1, 2022: Building soil with cover crops, crop rotations, and no-till

Tom and Stacie Novak hosted a field day on Thursday September 1 at their dairy farm in Highland, Wisconsin. Novak Farms is one of the member farms of the Iowa County Uplands Watershed Group, which MFAI coordinates, and the Novaks showcased conservation practices they use to build soil health, improve water quality, and reduce erosion.


Our host farmer Tom Novak shares about his practices, with the soil pit in the background.

When the Novaks bought the farm in 1997, they did conventional tillage on their crop acres. Over time, they have gradually increased their conservation practices. They started with reducing tillage to one pass. They also started planting an oat cover crop after corn silage, before adding in other cover crops into their rotation over the years. Around 5 years ago, they started doing no-till on some of their acres and they’ve been 100% no-till for the past two seasons. At the field day, we saw soybeans that had been planted into roller-crimped rye adjacent to a field that had rye harvested as grain earlier in the season and then planted into a cover crop mix with sorghum-sudangrass, oats, Austrian peas, red clover, tillage radish, and some leftover volunteer rye.

Jeff Denigen from NRCS highlighted that the soils in Iowa County, and on the Novaks’ farm, are mollisols—prairie soils with 10-11 inches of dark, silt-loam soil. Silt is non-cohesive and prone to erosion. In fact, Jeff shared that the loess soil we were standing on arrived there because of erosion in the first place, wind-blown from the west. These specific aspects of the soil make the practices that the Novaks have put into practice even more critical to their soil health and water quality goals—and their long-term success as farmers.


Dr. Jamie Patton of UW-Extension demonstrating water infiltration.

In the soil pit, Dr. Jamie Patton of UW-Extension outlined the soil health benefits of reducing tillage, keeping the soil covered with living roots, and the importance of crop diversity below-ground. Dr. Patton brought large pictures of the root structure of different grasses, legumes, and brassicas that showed how the varied root structures of the mix of crops play different roles in building soil structure, feeding soil biology, infiltrating water, and more.


Where the soil pit was dug, the cover crop mix had been planted on August 11, and three weeks later, roots of the two- to three-inch-tall plants reached down four feet to the bottom of the soil pit. The peas and clover roots were already nodulating, fixing nitrogen that Tom said he will credit to 100 units of nitrogen per acre. The peas will winter kill, and the clover will continue to fix nitrogen next spring before planting no-till corn.


Farmers in attendance asked a lot of questions to see how they could apply what Tom and his family have learned on their farm, including one about how much it cost them to plant cover crops. Tom shared that the seed in the mix listed above probably cost $45-50/acres, so with other costs it probably cost around $55/acre to plant the mix. Tom said the savings on nitrogen fertilizer, the weed management benefits, and improved water infiltration will most likely pay him back for the cost of planting the cover crop. Another farmer also noted that less complex mixes with fewer species are also cheaper to plant.

Farmer Tom Novak shows the effects of his soil health practices using a Slake test.

The morning ended back at the farmstead with a Slake test demonstration, where Tom compared the soil structure from the family garden that is tilled every year, a field that had been in no-till for two years, and a field that had been in no-till for two years. A Slake test is a simple test of the stability of soil aggregates in water where you put a clump of topsoil in a small wire mesh on top of a clear glass of water. The soil wicks water into it, and the better the stability of the soil aggregates, the less the soil breaks apart. The tilled garden soil quickly broke apart, and when dumped onto a paper plate turned into a muddy mush. The no-till soils largely kept their shape and held the soil together. If you want to try this out with your soil, check out this helpful document from UW researcher Rue Genger.


Thank you to the Novak family for hosting us and to our partners at UW-Extension, Iowa County Conservation, Compeer Financial, and Wisconsin’s Department of Agriculture, Trade and Consumer Protection, whose support and collaboration made this event possible.