Planting soybeans into a green cover crop isn’t as scary as it looks, Ida County Farm Bureau member Sam Bennett says. In fact, he’s found it easier to plant in tall rye than bare ground, with good soil moisture and fewer issues with crusted soils.
“We like to plant in growing rye before we terminate. It works really, really well,” he says.
But, Bennett adds, it’s important to have a contingency plan in place when the weather doesn’t cooperate, like during this year’s wet spring. And, it’s also important to follow crop insurance rules. In the western one-third of Iowa, that means terminating the cover crop at or before planting. In eastern Iowa, cover crops must be terminated before emergence, according to RMA guidelines.
For soybeans, Bennett thinks those termination dates could be pushed later in order to allow cover crops to grow longer. He’s participating in a Practical Farmers of Iowa research trial this year comparing cover crops terminated at soybean planting to those terminated four weeks later when the soybeans were at V2 or V3.
“If we want to see more cover crops on the landscape, we need to look at some of these rules (for termination) and allow them to grow taller where they do more good,” Bennett said.
At a field day in early July, the soybeans in both plots were at the same growth stage. “I don’t have any reason to believe it will yield any less,” Bennett says.
He’s also seen improved weed control by terminating cover crops later, offering the possibility of saving on herbicide applications. In fact, he has found weed control in plots with only cover crops was equal to plots where herbicides were used along with cover crops.
“We’re reducing our chemical bill by suppressing weeds,” says Bennett. “What we’ve seen is it doesn’t even take a lot of growth to get a degree of weed control.”
Gaining soil health
Cover crops have also resulted in improved soil health and are helping keep nutrients in place, he says.
“We like to keep the nutrients we paid for out of our water, and in our soil where we need it,” says Bennett, who is the sixth generation of his family on the Ida County farm that’s been in the family for 136 years. He’s also seen some unexpected benefits along the way, including more wildlife.
Cover crop acres in Iowa have boomed during the past five years, says Stefan Gailans, research director for Practical Farmers of Iowa. But, he noted, there’s still a long way to go to reach the targets outlined in a statewide strategy to improve Iowa’s water quality.
Bennett recommends farmers trying cover crops for the first time start on a small, manageable scale and outline clear goals for what they want to accomplish by planting a cover crop. Some management considerations include seed selection, seeding methods and termination. The biggest wild card is often the weather, which can affect the timing of seeding as well as the growth of the cover crop and efforts to kill it in the spring.
“There’s a lot of things to think about before you even order seed,” Bennett says. “They do take time and management. So that’s something you need to commit to. It’s really easy to give up on cover crops if you think they hurt your cash crop yield.”
A nine-year study by Iowa Learning Farms and Practical Farmers of Iowa shows cereal rye cover crops in a corn-soybean rotation have little to no negative effect on yield, and actually increased soybean yields in eight site-years and corn yield in two site-years.
In tracking results on his farm, Bennett says the benefits of cover crops outweigh the challenges.
“Not too many things on our farm get repeated if they don’t have a return on investment,” he says. “It’s part of the system now.”