Rye Cover Crops in Organic No-till Soybeans

By Dusty Sonnenberg, CCA, Ohio Field Leader, a project of the Ohio Soybean Council and soybean check-off.

Rye cover crops bring benefits, and biomass. Both need to be managed.

“Take care of your rye biomass,” said Lea Vereecke, a certified crop advisor and consultant with the Rodale Institute. 

Vereecke has been conducting research on organic no-till soybeans for several years at the University of Wisconsin, Madison with Erin Silva. She now works as an organic crop consultant with the Rodale Institute. Adequate cereal rye biomass is a key component in the successful production of organic no-till soybeans.

“Many farmers like tillage because it aids in nutrient cycling. Tillage moves organic matter and nutrients to different layers of the soil profile. Tillage can improve weed control and reduce the germination of certain weed species. It allows the soil to warm quicker in the spring, resulting in improved germination and crop emergence. It also aids in residue management and plays a role in disease control by burying that residue and speeding up the decomposition,” Vereecke said. “Those are the same reasons that organic farmers use tillage on their farms.”

No-till has gained popularity in conventional grain production for many reasons. 

“With no-till, farmers reduce the likelihood of soil erosion. No-till increases carbon sequestration. It improves soil health and the soil structure. Reducing tillage also reduces labor and fuel costs,” Vereecke said. “These are the same reasons organic farmers have an interest in trying to incorporate No-till into their organic practices.”

The philosophical struggle many no-till farmers make when considering a transition to organic production practices is the impact of re-introducing tillage to their operation. 

“When it comes to soil health and carbon sequestration, research conducted by the Pennsylvania organization, Pasa Sustainable Agriculture, found that it is possible to achieve optimal soil health while still conservatively tilling and cultivating to control weeds and terminate cover crops,” Vereecke said.

In 4 years of research at the University of Wisconsin, Madison, one key factor that influenced the success of organic no-till soybeans was the amount of rye biomass from the previous cover crop. The rye biomass plays a large role in weed suppression in the winter and spring months when there is not a cash crop in the field, and it continues that role after planting throughout the growing season. The rye also helps to reduce wind and rain erosion once it has been crimped/terminated, and it also helps to conserve soil moisture throughout the growing season.

Vereecke recommends getting the rye cover crop established between Sept. 20 and Oct. 1. This allows the rye to get established and grow well going into the winter. 

“Farmers need to treat the rye like they would the cash crop they are planting,” Vereecke said. “Make sure to plant the rye by Oct. 1. Make sure that there is good soil fertility. Make sure to have good seedbed preparation for good seed to soil contact and plant the rye at a seeding rate of 2 million to 3 million seeds per acre. Once farmers have more experience on their own farm, they can adjust the seeding rate accordingly to lower the seed costs, but it is important to have a good thick stand of rye biomass.”

Once the rye cover crop is well established and working, the termination of the rye and planting of the no-till soybeans comes next. 

“A roller crimper is a very effective tool to terminate the rye at the V3 growth stage,” Vereecke said. “Rye should not be crimped until it is at 100% anthesis, which is when all the anthers have been showing and begin to fall off the rye head. The rye will die and desiccate much faster if farmers wait to crimp until 100% anthesis. That biomass is your weed control for the year.”

Vereecke also recommends planting a named variety rye seed rather than Variety Non-Stated (VNS). A VNS rye seed may be a mixture of maturities and will not all reach anthesis at the same time. This will make uniform termination with a roller crimper more challenging.

Vereecke does caution farmers about planting organic no-till soybeans if a drought is occurring at soybean planting time. 

“Drought at organic no-till soybean planting time can be detrimental to the yields when planting into rye,” Vereecke said. “If it is exceptionally dry, it is better to not plant the organic soybeans into the rye, and instead just harvest the rye for seed. In any other situation, if heavy moisture occurs before or after planting, then organic no-till beans perform better. This is because you do not need to get out to do mechanical weed control when it is too wet. The rye will suppress the weeds.” 

Regardless if the beans are planted as 30-inch row beans or drilled at 7.5 inches, Vereecke also recommends making sure to plant the soybeans into adequate moisture. If it is the farmer’s first experience with organic no-till soybeans, she recommends planting 30-inch row beans. If there is a failure in terminating the rye or a weed outbreak, a high residue cultivator is still an option for weed control.