Gain From Crop Diversity
Abbey Wick sees the healthiest soils when there are three or more crops in rotation. The North Dakota State University Extension soil health specialist encourages farmers to take a systems approach to manage soil health. Part of that system is to diversify crop rotation so the soil microbes have different food sources, which ultimately makes soil healthier. Healthy soils are more resilient, says Wick. Resilient soils have more organic matter, which makes a difference during a wet May or a dry August.
“Farmers with diverse crop rotations have more predictable yields,” says Wick. Those soils are able to withstand more weather extremes.
Wick works with many growers who have diverse rotations. One example of this practice is to plant corn with interseeded cereal rye, then plant soybeans into the rye, followed by radish for seed. Next, plant winter wheat and finally bio strip-till corn. In North Dakota, it’s more common to have several cash crops, but that’s not the case throughout all of the Midwest. However, that doesn’t mean farmers shouldn’t be trying to increase crop diversity, says Wick.
“I recommend to farmers who can’t pencil out a third or fourth crop to try cover crops,” says Wick. “They are a huge benefit. It’s a way producers can get more diversity, and it’s a great way to start.”
That’s what Michael Vittetoe, a farmer near Washington, Iowa, opted to try for his operation. His grandfather, Leo, and father, Denny, have always been conservation-minded. Leo and Denny were planting cover crops and no-tilling for years, well before Vittetoe came back to the operation. He saw an additional opportunity with interseeding cover crops.
“I’d love to grow a different cash crop, but there’s no market,” he says.
His operation needs to haul the corn only ½ mile up the road – making it more difficult for other cash crops to be fiscally competitive.
“That’s why I ended up interseeding cover crops,” says Vittetoe. “I wanted something else in rotation, and it allows me to get a diverse rotation every year.”
This past spring, on April 20, he planted corn into cereal rye on a 5-acre test plot that has been corn following corn for 20 years. The cereal rye was terminated in early May, and he interseeded an 11-species cover crop mix on May 9. He chose a corn hybrid with upright leaves to not shade out the cover crop. Last year, he waited until the corn was at V5 to V6 to interseed, but he found, potentially due to lack of rain, the cover crop didn’t get great growth prior to corn canopy. This year, there was no problem with establishment. In fact, his concern was that it was too competitive.
“Last year, I didn’t have a yield hit, but this year I might,” he says.
Wick, however, does not recommend the practice of planting corn into living cereal rye as Extension research has not been shown to support this practice.
“I feel the entire ecosystem reaps the benefits of plant diversity – whether it be soil structure, soil biology, or insects,” says Vittetoe. “I choose interseeding because I’m trying to get plant diversity into the corn-following-corn system.”
Cover crops build root structure and soil aggregates. Think of it as super highways for water movement, says Wick. Yet, at the same time, they also help to increase water-holding capacity.
Cover crops manage water and provide a food source for microbes, and they keep soil in place by providing erosion control. “Crop diversity increases soil biology,” says Vittetoe. “I’m trying to find the natural balance.”
He hopes nutrients will become available to the corn crop as different cover crop species die.
5 food groups
“With soil health, you are trying to hit the five food groups (as Lee Briese, independent consultant with Centrol Ag, calls them) for microbes,” says Wick.
- Cool-season grasses, such as cereal rye or wheat
- Cool-season nonlegume broadleafs, such as radish or turnip
- Warm-season grasses, such as corn
- Warm-season nonlegume broadleafs, such as sunflower
- Legumes, such as soybeans
It’s important to remember that you don’t need to necessarily hit all five food groups in one year, says Wick.
It’s those food groups that Vittetoe is trying to establish with cover crops.
“I’m trying to balance cycles and establish nonrelated plants,” he says.
With more experience, it’s easy to switch up the system.
Once you grow a cover crop, there are options. You can graze it, harvest it, or leave it in the field for biomass.
“If there’s a way to get something out of it, you should,” says Wick. “You’re still feeding the soil.”
Wick hears people say producers need to return to or mimic the natural ecosystem, but the Midwest will never return to a prairie. That’s not what farmers are in the business of, she says. Instead, finding ways to increase diversity while still being profitable is key. What’s most important is that it fits into a farmer’s system, says Wick.
“Simple is a good start,” she adds.
For Vittetoe, it’s about proof of concept. So far, it’s financially balanced out. “The seed cost and the herbicide product cost are equivalent to my standard herbicide,” he says.
While he still tweaks the system, like timing and weed management, he figures he can make mistakes on a small scale before implementing them on a large scale.
For farmers with a monoculture, such as corn following corn, Wick suggests radishes as a good option to start. For those who plant soybeans following soybeans, she recommends that farmers try rye or radishes since they are more inexpensive options. One tip, says Wick, is to always consider the current crop and to have a termination plan in place.
“That will keep you from making mistakes,” she says.
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