Fall field days showcase best practices for water quality

Cora Fox contributed to this blog.

Fall is always a busy time for harvest, holidays, and sports. The season is also used to prepare for the next year, as farmers buy seed, implements, and attend conferences and field days. This year, water quality and soil health have been recurring themes at events in Iowa.

Iowa Learning Farms hosted a Soil Health & Cover Crop 101 Field Day in early November at Gordon Wassenaar’s farm in Jasper County, in cooperation with the local Soil and Water Conservation District office and Natural Resource Conservation Service staff.

District Conservationist Curt Donohue used a rainfall simulator to show how cover crops and no-till can greatly reduce runoff and boost water retention in the soil. Helping soil hold its own water can increase yields, as crops can better withstand drought periods.

Wassenaar shared his experience in finding the right cover crop mix for his farm, and how cover crops have lowered costs by decreasing resistant weeds. Cover crop demonstration plots showed a variety of seed mixes and seeding rates.

“I wonder what Norman Borlaug would say to Iowa’s recent push for cover crops if he were alive today," Wassenaar said. "I hope Borlaug’s influence is not lost on future generations.”

In mid-November, two field days were hosted by the Iowa Farmers Union, Practical Farmers of Iowa, the Iowa Environmental Council, and the Natural Resources Defense Council, with assistance from the Iowa Department of Agriculture and Land Stewardship and the U.S. Department of Agriculture Risk Management Agency. The topic was a new discount on crop insurance premiums for using cover crops.

Farmers can currently get cost-share support for trying cover crops to the tune of $25 per acre for the first year, then $15 per acre for returning users. For farmers trying no-till or strip till, cost-share is $10 per acre, or for farmers using a nitrification inhibitor in the fall, it’s $3 per acre. However, after two years, the cost-share is no longer available. This crop insurance discount, at $5 per acre, is to continue rewarding farmers who stick with cover crops and provide an incentive for those still on the fence.

The benefits of organic systems were on display at a tour of Aaron Lehman’s farm near Slater. Soil health benefits could be felt with the softer, spongier ground seeded in rye, following corn. Yields, water retention, and soil organic matter are all improved in his organic corn, compared to his conventional corn. Lehman’s use of cover crops and extended rotations is an on-farm application of research by Matt Liebman from the Leopold Center for Sustainable Agriculture at Iowa State University.

Dr. Cynthia Cambardella of Iowa State University presented research on improved water quality in organic systems at the Iowa Organic Association Conference in late November. She studies water quality and compares practices on an organic research site in north central Iowa.

In 2006, the site was converted from a conventional corn-soy rotation to an extended four year cycle of rotations under organic practices. No chemicals have been applied to the farm since 2006; instead corn and soybeans are rotated with oats and alfalfa. Only composted manure is used as nitrogen fertilizer. Tile drainage of the entire farm was isolated on each of 30 test plots. Overall, nitrate loads were reduced by more than 50 percent in the organic versus conventional systems.

All events showed that farmers are looking at soil health, water quality, and nutrients, as well as yields. Cost savings, coupled with incentives or organic practices, proves that cover crops can be economical in the long run. Every farm is different, and farmers across Iowa are finding methods that work for them.