T-R PHOTO BY ADAM SODDERS
Once fully harvested this fall, some soybean fields like this one in western Marshall County will be planted with cover crops like winter rye to help with soil health until spring planting.

Browning and yellowing crops in fields flanking Central Iowa highways are a sure sign that harvest is not far away, and many area farmers are thinking beyond getting their main crops out of the field.

Cover crops – crops planted in fields that most of the year are used for corn and soybeans – are used by many farmers in the state. The practice has several benefits and, for many farmers, is worth the cost of putting in the ground.

“We mainly plant cover crops for erosion control, that’s my No. 1 goal of the cover crops,” said western Marshall County farmer Craig Pfantz. “Any soil health benefits, improving the soil irrigation, soil structure, sequestering nitrogen, all the other side benefits, they’re secondary for me.”

After the main crops are harvested, Pfantz said he plants winter rye in fields that will be planted with soybeans in the spring. Oats are planted in fields that will grow corn in the spring.

“Oats do not overwinter. They die, so you’ll get some growth and then it will die when it gets cold, so you don’t have that competition with the corn,” he said.

Pfantz said that is important, because oats and corn are both grass species. Winter rye, as its name suggests, can be planted in the fall and survive the winter to bloom again in the spring.

Just before soybeans are planted in a field filled with winter rye, Pfantz said he will kill off the rye so the beans can be planted. He said that has worked very well for beans in recent years.

Along with using cover crops, Pfantz said not tilling the soil in the spring has helped keep the rich topsoil in place, a key part of year-to-year crop success.

Marshalltown-area farmer Matthew Burt said he also uses cover crops on his fields.

“We spread mostly winter rye. It is a hardy plant and and is low maintenance,” he said. “We spread the rye with a spreader after a field is harvested in the fall.”

Like Pfantz, Burt said the benefits of cover crops are manifold, including:

• Reducing nitrate levels in nearby bodies of water

• Reducing soil erosion because the plants’ roots hold the soil together in the absence of corn and soybean plants

• Increasing the overall organic matter in soils

• Decreasing water runoff by helping soil absorb rain water more rapidly.

While Pfantz said he has not seen a big uptick in the use of cover crops in his area, Burt said there has been an increase in their use throughout the state.

“There have been a lot of educational workshops and studies detailing the benefits of cover crops,” he said. “There has been cost share opportunities for farmers to utilize. And farmers care about the soil and water here in Iowa and want to do the best to maintain and improve it.”

Cover crops went from being used on about 10,000 acres of Iowa farmland a decade ago to being used on about 1.5 million acres in 2017, according to the Iowa Farm Bureau.