Soil health discussed at Cover Crop Field Day

Soil health was the topic of conversation at last week’s Jasper County Cover Crop Field Day in Prairie City. A couple dozen farmers and community members gathered at Gordon Wassenaar’s farm for an afternoon filled with insightful information.

Natural Resources Conservation Service (NRCS) Soil Health Specialist Doug Peterson, with the help of NRCS’s Alan Wedemeyer, executed a rainfall simulator. The simulator showed how tilled soil leads to much more runoff, and therefore, prevents the rain water from soaking into the soil and helping crops grow.

Cover crops also play a role in soil health by prevent erosion and keeping nutrients in the soil. The rainfall simulator featured soil that was not tilled, soil that was tilled once and soil that was regularly tilled. The overly-tilled soil with no cover crops did not hold water well. Instead, most of the simulated rain ran off the surface.

For the sake of simulation, run-off water was collected in a bucket below the soil to show tillage and cover crop impact. In actual farming practices, that run-off water would find its way to rivers and streams, polluting the water and causing floods.

According to Peterson, less than 10 percent of Iowa farmers are implementing no-till systems for their crops. The popularity of tilling, despite the science showing how harmful it is to both soil quality and water quality, is a social thing, Peterson said.

For generations, farmers have been tilling because that’s what their fathers and grandfathers have always done. It wasn’t until the last couple decades the science behind no-till systems has come to the forefront, Peterson said.

Cover crops are used even less. An estimated 2 to 5 percent of Iowa’s corn and soybean farmers utilize cover crops. However, cover crops have been on the rise. Iowa Learning Farms’ 2016 Field Day Evaluation Report revealed the number of acres with cover crops grew from 10,000 to 623,000 in the last seven years.

NRCS Jasper County conservationists, Curt Donohue and Holly Giombi, said the increased use of cover crops right now is located in small pockets and neighborhoods. Hosting field days is a way to stoke word of mouth, Giombi said.

“I think once someone really is focused on starting cover crops, and they do it, they see the benefits,” Giombi said. “Then they’re likely to continue and spread the word, too.”

Bert Strayer, of La Crosse Seed, was also at the field day. He talked about the increase of cover crops over the last 5-10 years. Certain seeds that he has long sold were never marketed as cover crops until recently. Strayer stressed the importance of building around a system. Not every farmer’s needs are the same.

There are many different cover crop options. As part of the field day, the group went out into Wassenaar’s field to observe the effectiveness of different crops. Some popular cover crop options include rye, oats and winter wheat.

Wassenaar has hosted Jasper County Cover Crop Field Day for the last four years. He is optimistic about the future of farming. Changes will be necessary to make farming more sustainable, and the Prairie City crop grower thinks Iowa farmers will respond.

“We are agriculture — that’s what drives this engine,” Wassenaar said. “We have to figure out how we can adjust and fit to the world.”