Cereal rye cover crop.
Cereal rye cover crop.

The Minnesota Corn Growers Association (MCGA) is expanding its cover crop research through the University of Minnesota (U of M) with two new projects focusing on the potential for cover crop mixes throughout the state to reduce nitrogen fertilizer in waterways and in tile drainage systems.

“Minnesota’s cool climate and short growing season makes using cover crops challenging in many parts of the state,” said Dr. Paul Meints, MCGA’s research director. “Our research focuses on making cover crops a more viable option for farmers, and works to quantify the conservation benefits of cover crops when it comes to keeping nitrogen out of our waterways.”

Cover crops and tile drainage

A project being led by Jeff Vetsch, soil science research manager at the U of M’s Southern Research and Outreach Center in Waseca, will examine how cover crops can help reduce the amount of nitrogen entering waterways through tile drainage systems.

“We’re going to interseed cover crops late in the growing season while corn and soybean are still in the field,” Vetsch said. “We want to see how much nitrogen can be intercepted by cover crops and thereby minimize nitrogen loss through tile drainage. We believe the potential is there for real benefits.”

If cover crops can prevent a significant amount of nitrogen fertilizer from leaving fields through tile drainage, it will help protect area water quality. It’ll also improve a farmer’s bottom line by keeping the nitrogen on the field where it can support crop growth.

Vetsch plans to compare different types of cover crops. Cereal rye remains in the field during winter and is terminated before planting in the spring vs. annual cover crop blends that die in the winter. Cereal rye has been a successful scavenger of nitrogen in other states, and Vetsch would like to measure its effectiveness in Minnesota.

Three different nitrogen rates will be used: no nitrogen fertilizer or the soil’s natural nitrogen level, the U of M’s recommended nitrogen fertilizer rate and 15-20 percent above the U of M’s recommendations.

“Multiple rates of nitrogen are needed to completely understand how cover crops impact nitrogen availability for corn,” Vetsch said.

Cover crops throughout the state

When it comes to cover crops, what works in a dryer region like Southwest Minnesota might not work in a cooler region like Northern Minnesota. U of M assistant professor/cropping specialist Dr. Axel Garcia y Garcia is set to begin work on a project that hopefully can help farmers better understand what types of cover crops might work best on their own farms.

“I’m personally excited that the Corn Growers funded this project,” Garcia said. “How you incorporate cover crops might change based on where you’re farming. We’re going to be looking at cover crop mixes from Grand Rapids all the way down to Lamberton and Waseca.”

When it comes to better managing nitrogen fertilizer, Garcia’s project looks at two key things: 1) Effectively managing cover crops to improve nitrogen use efficiency to keep it out of nearby waterways and 2) determine the effect of cover crops on water and nitrogen use in corn.

Garcia will also try to quantify the amount of nitrogen that leaves fields through leaching with different cover crop mixes. Another goal of the project is to examine how various cover crop mixes can enhance diversity in our ecosystem.

“It’s important to try and get as much quantifiable data as possible,” Garcia said. “That information is good for both farmers and the general public to know.”

Cover crops on corn fields may be seeded at either the beginning or end of the growing season. On soybean fields, cover crops may be seeded near maturity or post-harvest due to the overhanging canopy of the soybean plant.

Plant disease and weed population will be monitored throughout the project’s duration. Many farmers already use annual rye as a cover crop, which is currently not researched at the U of M. Garcia plans to use annual rye and compare its results to winter rye.

More information

MCGA, working in close partnership with the Minnesota Corn Research & Promotion Council (MCR&PC), invests in about $4 million annually in research efforts to help farmers better manage nitrogen fertilizer, protect water quality and farm more efficiently.

To learn more about MCGA’s research efforts, including its research into using cover crops in Minnesota, go to www.mncorn.org/research.