An Ag-education

PRAIRIE CITY —  Iowa’s water quality crisis is a problem for everyone, urban and rural residents alike.

Although the debate for who’s to blame has been contentious, many farmers are trying to do something about agriculture’s impact on the state’s waterways.

In partnership with National Resource Conservation Service personnel at the Newton USDA Service Center, Prairie City farmer Gordon Wassenaar hosted a cover crop field day Nov. 8 to educate Jasper County and other central Iowa producers how keeping fields covered year-round improves soil quality and prevents runoff from entering nearby waterways.

About two dozens farmers gathered on Wassenaar’s farm south of Prairie City, to hear from soil scientists who demonstrated cover crops in action. The non-commodity plants are typically planted directly following harvest and have two main affects — they protect soil from weather erosion during winter months and their roots capture nutrients leaving them in the soil.

Patrick Chase is an NRCS soil scientist based in Newton. At the field day he demonstrated how active, health biology in top soil can better withstand erosion caused by water.

Chase took two clumps of soil, one with a healthy level with microorganisms and the other with a less robust microbiome and dropped them each into a cylinder of water. The clump with microorganism diversity largely held together while the other broke apart. Holding the soil together kept the water clean and mostly free of topsoil contamination.

Chase did a similar demonstration with soil samples from till and no-till fields. The result from the no-till sample had similar results to the sample with healthy microorganism biology.

Chase said cover crops have been shown to keep the microbiology and nutrient content of the soil rich throughout the winter months. Coupled with no-till methods of field maintenance, the demonstration showed the field day attendees the direct results of the practices, how it affects water quality and mitigates top soil loss.

“It’s that force of the water getting into the soil aggregate which breaks it apart. If you have no stability, that thing just dissolves,” Chase said during the no-till demonstration. “That’s what happens when you have a big rain. Why do you have erosion? Our soils have been beat up, they’re tired and they just fall apart. That’s why they need the biology, they need roots, they need cover to protect them.”

Outside near the cover crop demonstration fields, Chase demonstrated the affects of a torrential rainfall on top soil using the Iowa NRCS Rainfall Simulator. It rains on four field patches with varying degrees of cover and tillage — from bare dirt with full tillage to a no-till field with cover crop.

The rain runs off into collection buckets below. The soil loss on fields with little cover is much more substantial and the patches with high tillage is also dry, showing no-till allows moisture to better soak into the top soil.

“When you run any type of tillage through, you make every chuck of soil a little bit smaller every time,” Chase said. “How easy is it for you to run up this hill and breath through a straw? That’s what you’re forcing your soils to do with very little input, very little resources for water, nutrients and air. Any type of disturbance moves or even eliminates your biology, too.”

The Nov. 8 event was the second cover crop field day on Wassenaar’s farm, and one of only a handful to be hosted on privately owned fields in Iowa. The Prairie City farmer is already known in the Iowa ag community for hosting international industry guests in multiple events each year.

Wassenaar has been applying cover crops to his fields for six years, starting with a single variety of cereal rye. He now plants several seed mixes on the total of his 1,700 acres of corn and soybean fields.

Wassenaar partnered with NRCS one year ago to develop a test plot on his sweet corn field to test the effectiveness of various cover crops in top soil conservation, runoff mitigation and maintaining nutrients.

The Prairie City farmer said the test plot is both for his own research and to educate other Iowa farmers on the positive impact cover crops can have on Iowa’s water quality and field productivity.

“The idea of the plot is to get an idea of how different (cover crops) would react and to have an open house to let other people see and compare the different seedings,” Wassenaar said.

The plot shows farmers cover crop growth from two separate planting dates with a variety of grasses, legumes and brassicas.

Wassenaar does not do side-by-side yield trials to calculate any bushel increases from adding cover crops, but the farmer said he is certain the cover crops have cut erosion on his fields.

“With Iowa’s water quality issues it fits in really well with that. We just think it’s really something we need to be doing,” Wassenaar said. “We farm lightly rolling ground and erosion can be a factor. We’ve been doing no-till since the early 1990s, and we think cover crops fits the no-till program very nicely.”

Contact Mike Mendenhall at mmendenhall@myprairiecitynews.com