Cover crops growing at Clayton County Fairgrounds

A cover crop demonstration plot at the Clayton County Fairgrounds will be the focus of an open house on Monday, April 22, from 10 a.m. to 2 p.m. Area crop adviser Edmund Ruff, who developed the idea, is pictured at the site with Iowa Soybean Association representative Suzanne Shirbroun. (Photo by Audrey Posten)
The latest grandstand attraction at the Clayton County Fairgrounds isn’t a cover band, but a cover crop.
A demonstration plot can be found in the lawn between the main stage and grandstands, occupying about 90 percent of the lawn. The plot includes multiple varieties of cover crops, seed blends and planting techniques. A total of 23 different sub-plots are on display.
The site will be featured as part of an open house from 10 a.m. to 2 p.m. on Monday, April 22, at the fairgrounds in National, to address the importance of cover crops in farming and improving water quality. The public is invited to tour the demonstration plots and ask questions. Professional agriculture experts from local, state and national organizations such as ISU Extension, Iowa Soybean Association - Research Center for Innovation, USDA/NRCS, IDALS, Iowa Water Quality Initiative, Clayton County Pork Producers and more have been invited to address questions attendees may have on cover crops. In addition, the Clayton County Pork Producers will serve grilled pork sandwiches.
The Practical Farmers of Iowa (PFI) have also scheduled a field day this summer to observe the cover crop plots as part of the association’s summer farmer-to-farmer learning activities. The PFI field day will start at 4 p.m. on Thursday, June 20, at the fairgrounds, before going to the Edmund Ruff family farm north of National for an in-the-field discussion on managing cover crops in corn and soybean cropping system. This summer’s event is also open to anyone with an interest in farming and cover crops.
The demonstration plots will be reverted to ground cover before the county fair in August, ready for the sea of lawn chairs that will accompany the great shows at this year’s fair.
“Whether you’re new to PFI field days or a yearly attendee, you’ll find a welcoming atmosphere, a spirit of curiosity, a culture of mutual respect and farmers openly sharing their knowledge and experience,” the PFI said. “Our events are led by our farmer members. We know they are the experts on their specific farming systems.”
The idea for using the fairgrounds for a cover crop demonstration grew out of a discussion at an Iowa Soybean Association agronomy clinic in 2023, attended by area crop adviser Edmund Ruff. The next week, Ruff went to the Clayton County Fair’s rodeo. The area between the grandstands and stage was tilled up to create a soft surface for the bucking bulls and bull riders. While watching the “Bull Bash,” the idea sprouted in Ruff’s head that this site would make a great demonstration plot for cover crops. A bare piece of land during the late summer in the heart of Clayton County would need to be planted to something soon, so why not cover crops? The fairgrounds site is easy to access from Highway 52 and features off-road vehicle parking and restroom facilities, and the site’s primary use, the county fair, would not be using the grounds until late summer. What a great spot for an agricultural education demonstration plot, Ruff thought.
The Clayton County Fair Board of Directors approved seeding of plots for the various cover crops. The Iowa Soybean Association agreed to help. Ruff sourced seeds from St. Olaf AG Sales & Service, a cover crop seed supplier, from Iowa Soybean Association conservation agronomist Evan Brehm and from resources though Sarah Plaht, MFL MarMac High School agriculture instructor.
The cover crops were seeded by hand on Sept. 13 and again on Sept. 25, in plots measuring 10 by 16 feet. A third seeding at the demonstration area, on Oct. 25, used a no-till drill to plant a mix of winter rye and winter camelina. The mechanical seeding technique demonstrates a recommended seeding rate required for cost share programs prescribed by the USDA’s Natural Resources Conservation Service and is a rate that allows for the planting of crops in what is referred to as “planting green.” The different planting dates should assist farmers in evaluating the results of biomass production with different start dates.
Cover crops have gained a lot of interest in recent years as a farm management practice in Iowa. The reasons are twofold: Cover crops improve water quality and capture and store carbon in farm fields as organic matter.
Water quality improves because cover crops reduce erosion and nutrient loss from farm fields by capturing nutrients in the form of plant biomass when the primary crop is not growing in the field. This biomass production is what makes the cover crops attractive to players in the carbon emissions market.
Cover crops are essential for healthy soil at the farm level, and cover crops augment soil health in fields. In many cases, soils that produce high yields are not synonymous with healthy soil, and rapidly deteriorate over many years. Good agronomy management recognizes that soils function better if key practices are put into a farming system to promote healthier soil.
Cover crops address three underlying principles to soil health: maximizing continuous living roots, maximizing biodiversity and maximizing soil cover. These principles are critical at the farm level. Every farmer can embrace these concepts to ensure they act as stewards of the soil to ensure the land stays productive for an eternity, and not just a season.
A new practice being used on farms is soil health testing, and soil testing laboratories now offer soil health tests. Similar to a conventional soil test, a soil health test takes a soil sample from a farm’s fields. Special reagents are used to measure nutrient availability in the soil. These reagents mimic the secretions of roots and measure nutrient availability to the root hairs found on crops. In healthy soil, results will show increased nutrient availability, thus fewer fertilizer nutrients need to be applied to get similar production results.
Soil health testing shows carbon and nitrogen are the key nutrients soil microbes rely on for life, and a proper balance of carbon and nitrogen can be managed, resulting in healthier soil. The addition of cover crops to a farm’s crop management system can improve the heath of the soil on that farm.
A soil health test was performed at the fairgrounds demonstration plot. Those attending the April open house will have the opportunity to review the results to learn more about soil health testing.