On-farm demonstrations show real world benefits of alfalfa-corn rotation

Written by Jonathan Eisenthal

At 250,000 acres, the amount of land traded between corn and alfalfa in a regular rotation represents only about three percent of Minnesota’s total corn crop acreage.

Yet, information developed by a University of Minnesota agronomy research team, with financial backing from Minnesota Corn Research & Promotion Council, shows the value of planting corn into alfalfa. This rotation increases the nitrogen levels in the soil and builds up organic matter and reduces weed seed banks, among other benefits.

Not only might this research sway additional operators into the practice, but also it will help farmers who do use an alfalfa-corn rotation to make the most out of alfalfa’s potential to increase the productivity of land where it is being raised.

“One of the biggest concerns for farmers right now is the high cost of inputs, nitrogen fertilizer for one—alfalfa supplies nitrogen to corn,” said Extension Corn Agronomist Jeff Coulter, the lead scientist on the research project. He said, “Most of the research on the amount of nitrogen that alfalfa supplies—that data is outdated. It’s based on old yield levels, corn hybrids not in use anymore, and so on—so farmers don’t have very much confidence in guidelines based on that old information. So we are relooking at that. There are economic and environmental penalties for over applying fertilizer, but there are also serious economic penalties if you don’t apply enough. We’re trying to get a better handle, to provide corn growers a better idea of how much fertilizer they might need to apply in this rotation.”

Nancy and Jerry Ackermann are believers in the benefits of a corn-alfalfa rotation, and one of the four upcoming field days will be held at their Lakefield, Minnesota farm.

The four field days will be fast-paced (two to two-and-half hours total) and will feature a few quick presentations from experts, tours of the research plots and refreshments. The key element will be bringing together operators who use an alfalfa-corn rotation to trade information about what works for them—from cultivation systems to when and what herbicides they utilize in the transition from alfalfa to corn.

“There’s the four replications that Jeff (Coulter), Mike (Russell) and Matt (Yost) set up—they wanted to see if there are differences with chisel plowing under alfalfa in the fall versus the spring, and then there’s plenty of space where we did it in our usual way—planting the corn no-till into the alfalfa,” said Jerry Ackermann. “Nancy is a real numbers person, and what she says is that she is watching to see where the best rate of return is.”

Not only does Nancy pore over the farm operation books to assure maximum ROI, she calibrates the on-board yield monitors, drives the large-square balers and the combine and assesses the maps generated from the yield information to assess the performance of crop varieties and to tweak the amounts of nitrogen and other inputs that they apply at variable rate, with the help of GPS positioning systems.

Nancy and Jerry have planted corn, soybeans and alfalfa in rotation for a number of years, and recently discovered the value of planting corn in a no-till cultivation system into alfalfa after three to four years of raising the forage legume.

For the Ackermanns, turning no-till corn into alfalfa started when heavy spring rains left standing water over a stretch of 80 acres that subsequently froze, ruining the alfalfa stands there. They knew from experience that planting alfalfa in the spring rarely turns out well. The Ackermann’s crop consultant, Jim Nesseth, of Extended Ag Services, Inc. in Lakefield suggested they try no-till corn there.  A neighbor was able to lend them a no-till planter.

“It was unbelievable—a great stand. At harvest, it averaged 175 bushels an acre despite a hot, dry summer, and the fact that one end of the field is really sandy,” said Jerry Ackermann. “What makes me really happy is to be continuously trying new things and learning how to do what we do better. I especially like to learn ways to make money without spending too much….with nitrogen, I wouldn’t spare it where it is useful. And I’m not opposed to 200 bushels per acre yield. But when Nancy runs the numbers and we are making a better return with a little less nitrogen and a yield of 190, that’s what we go with. There’s no sense not getting the full value for the nitrogen you use, or putting nitrogen down a tile line instead of using it where it can be taken up by the plants.”

“Minnesota corn growers are very progressive,” said Coulter. “As a rule they have very good yields, they are very efficient and they are funding research to help them be more efficient and obtain even higher yields. More efficiency in applying fertilizer has outcomes in both economic and environmental terms, and that is why they are funding this type of work.”

Jerry Ackermann said an alfalfa-corn rotation has lots of benefits, but it might not be for everyone. The window for each of the four yearly cuttings is fairly narrow, and a sizeable amount of capital gets tied up in the baler and other specialized equipment. But he said it has been an excellent cash crop for them.

According to Coulter, one thing that could increase the market, and so draw more operators into this rotation, would be progress in the development of next generation biofuels. Some experts point out that the alfalfa leaves, which are high in protein, can be separated for use as animal feed, while the woody stems, which have less value as a feed product, may make an excellent feedstock for cellulose-derived ethanol. Coulter noted that a lot of developments have to fall into place before this could happen, but alfalfa’s agronomic value could help make this an economically viable opportunity in the near future.

The field days are free and open to the public: 
Friday, June 25
Montevideo—12:30 p.m. to 3:00 p.m.
130 50th
Ave. NW

Monday, June 28
Chatfield, MN – 12:30 p.m. to
3:00 p.m. – 1/2 mile north of the
intersection of Hwy 30 and Hwy 11.
Wednesday, July 7
Lakefield, MN – 12:30 p.m. to
3:15 p.m. – 39750 820th Street.
Friday, July 9
Norwood, MN – 12:30 p.m. to
3:00 p.m. – 18875 Co. Road 34.
Get more information about the alfalfa-corn rotation research and the field days at:


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