GOODHUE, Minnesota — Ed McNamara, Goodhue County farmer and supervisor of the Soil and Water Conservation District Council, continues to refine his use of cover crops for forage, fertilizer and soil health.
This season, McNamara will be experimenting with row width, spacing and different types of manure. It was part of a three-year research project by the University of Minnesota and Cannon River Watershed Partners that ended in 2021.
McNamara farms land in Belle Creek Township that his grandfather purchased in 1928, and he began farming with his father in 1978, milking registered Holsteins for 25 years. His farm sits within three watersheds that drain into the Mississippi River – Hay Creek, a trout stream – and the Zumbro and Cannon Rivers. The water table is high, the soil is a silty clay loam, he says.
“That makes it interesting, but it also presents opportunities to adopt tillage practices and cover crops to reduce the impact on the water below us,” McNamara said.
Supervisor of the Goodhue County Soil and Water Conservation District Board for the past 24 years, McNamara is also a Certified Crop Advisor. McNamara enjoys helping other farmers who might be interested in cover crops and recently discussed what worked for him, what didn’t and how he adapted.
“We have understood the agronomic side. Now we have to change the management styles of individual growers,” McNamara said. “If you only use your field for five months of the year, the other seven months of the year it could produce one or even two crops. Isn’t that a more efficient use of the most expensive asset you have? »
McNamara experimented on his own, with help from the USDA’s Natural Resource Conservation Service, and through research projects.
He hasn’t plowed soybeans into corn stubble every year since that first cost-cutting experiment in 1997. The cover crop of oats and peas he planted as a preventive measure in 2013 fed cattle in November and expanded the soil health list. practices he made permanent on his 350-acre corn and soybean farm.
“I really haven’t looked back,” McNamara said of no-tillage.
NRCS assistance allowed him to experiment early with cover crops, through the Conservation Stewardship Program, and nitrogen application rates through the Quality Incentives Program. of the environment.
In a three-year research project that ended with the 2021 harvest, McNamara intercropped cover crops between 30-60 and 90-inch rows of corn. A University of Minnesota agronomist and Cannon River Watershed Partners conservation program manager worked with him and three other farmers to determine how row width affected corn yield and cover crop biomass and whether a wider spacing could be profitable.
Alone in 2021, McNamara planted two-row corn 7.5 inches apart in east-west rows. The spacing allowed harvesting with a 30 inch head of corn. The staggered plants in the double rows exposed the cover crop to more sun, he said. Rows planted north-south get three to four hours of sun a day, McNamara said, while east-west rows get more shade.
This spring, he will alternate 10-foot-wide strips of four 30-inch twin rows of corn with 10-foot-wide strips of cover crops. After each cover crop harvest, he will apply a different type of manure – beef, turkey and pork – and then plant corn on that strip the following year. The goal: to maximize the nutrient value of cover crops, determine the amount of phosphorus absorbed by intensively managed cover crops, and potentially eliminate the need for commercial fertilizers next year.
McNamara was one of four farmers from Goodhue and Rice counties who participated in a three-year research project to determine if planting cover crops in corn could be profitable.
The Clean River Partners and University of Minnesota study examined how corn row spacing affects not only yield, but also the growth and profitability of forage cover crops. A Minnesota Department of Agriculture Sustainable Agriculture Project grant supported the study, which was completed in 2021. Clean River Partners plans to post the final results on its website later this spring.
“What we were really looking at was if we plant corn in wider rows, can we grow more cover crops, and if we grow more cover crops, what impact will that have on grain yield,” said Alan Kraus, conservation program manager at Northfield. Clean River Partners.