Though technological advances in the last decade have exponentially increased the quality of soybeans, there are practices that Upper Midwest soybean growers have implemented for centuries that contribute to the superior quality of northern-grown soybeans.
One such practice is healthy crop rotations.
“Crop rotations were one of the earliest developments identified as a way to have more stability in crop yields,” said Seth Naeve, soybean researcher at the University of Minnesota.
Across Northern Soy Marketing’s (NSM) member states – Minnesota, North Dakota, South Dakota, Nebraska and Wisconsin – crop rotations are a critical component to farming operations, though they look different from farm to farm and field to field. In South Dakota, NSM Vice Chair Mike McCranie implements a fairly straightforward – but not without its challenges – corn, soybean rotation.
“It’s pretty simple,” McCranie said. “We try to plant half corn and half soybeans. It doesn’t always perfectly end up 50/50 depending on circumstances but we do our best.”
To the east, NSM Director Glen Groth operates a bit more of a complicated crop rotation near Ridgeway, Minn.
“It all depends on the field,” Groth said. “Some fields we just do corn, soybean rotations. We have other fields where we just do continuous corn and, on some fields, we have corn, soybean and vegetable crop rotations. And, sometimes, we have another rotation where we raise corn and hay. So, we have a lot of rotations that all depend on the field, terrain and conservation needs.”
There are a few ways that crop rotations benefit growers. First and foremost, it helps deter pests, weeds and diseases.
“Generally, corn does better in a field after soybeans and vice versa,” Groth said. “Crop rotations break up disease and pest cycles, which is the main reason for them.”
Growers spend a significant chunk of capital on various crop protection measures, but crop rotations are a defense that farmers don’t have to pull out their wallets to execute.
“Rotating crops reduces the buildup of any kind of residual pest that might be hanging around and continuing to reduce yield,” Naeve said. “So, weeds, insects, diseases, all of those things can be reduced just by changing up the rotations.”
Furthermore, switching up the crop grown in each field benefits the nutrients in the soil and can be utilized by the plant.
“Soybeans produce a little bit of extra nitrogen that can be used by a corn crop the following year,” Naeve said.
Another benefit of crop rotations is keeping fields from being overrun with residue.
“There are also some logistical benefits like the amount of residue,” Naeve said, “because corn has very high levels of above ground biomass that needs to be degraded and growing corn after corn after corn in one field builds a lot of biomass. In ancient times, they would just burn it, but we don’t do that anymore. So, one way to reduce that build up is planting a different crop.”
There are many benefits of crop rotations, but there are also challenges.
“Mother Nature is the biggest challenge for us,” McCranie said. “For example, some years we may end up with prevent plant, so our 50/50 ratio gets thrown off.”
Prevented planting is a failure to plant an insured crop by the final planting date, which is designated in grower’s crop insurance policies. These dates vary by crop and by area. For growers who use crop rotations to introduce diverse crops into their operation, they have to consider demand.
“Market fluctuations are a challenge,” Groth said. “You have to consider market dynamics when adding crops into a rotation, like hay. Some years you can’t give it away, other years it’s worth its weight in gold.”
At the end of the day, by implementing crop rotations, Upper Midwest growers improve the quality of their soybeans.
“We’ve had to put soybeans on soybeans, and you end up with more disease, especially fungi,” McCranie said. “The area that I’m in, we do have a white mold issue, so crop rotation helps with that.”
