Linn County farmers highlighted a range of conservation practices last week as they took about two dozen politicians, city and county planners, and community leaders on a tour to show how farmers are helping meet the goals of Iowa’s Nutrient Reduction Strategy.
"We need to get people involved and answer their questions," said Curt Zingula, natural resource chair for the Linn County Farm Bureau, which organized the tour along with the Linn County Soil and Water Conservation District, Natural Resources Conservation Service and Linn Co-op Oil Co. "As farmers, we’ve got to be proactive."
The tour included a look a shallow water wetland area, a riparian buffer, a modern hog barn, strip-till and variable rate fertilizer technology, all of which play a part in reducing nutrient losses from farms. Several farmers participated in the tour to answer questions about farming practices.
"There’s no way in one morning we can cover all the conservation practices farmers are doing," Zingula said. "This is not a tour to snowball everybody into thinking everything is fine. We know we have issues to address, and we’ve actively been addressing them."
Steve Hershner, Cedar Rapids utility manager, said the tour was beneficial as he explores opportunities to work with farmers to establish conservation practices near the city’s water sources.
"It’s one thing to talk about these things as abstract concepts in a board room. It’s totally different to come out here and see it in person," he said. "I’ve heard about a lot of these practices. It’s good to see them in person."
Jon Gallagher, a resource conservationist with the Linn County Soil and Water Conservation District, explained how a 10-acre shallow wetland west of Central City is helping filter nitrates from the water in the Indian Creek Watershed. The land had been farmed with inconsistent results until 2001, when the owners sought USDA assistance to install the wetland, which receives drainage from 500 acres in the watershed, Gallagher said.
"What we wanted to do here is intercept the water flow coming through the field," he said. "These edge of field practices are really effective."
Wetlands provide an average 50 percent reduction in waterborne nitrates, said Greg Brenneman, an Iowa State University ag engineering specialist.
"It’s probably one of the most effective practices," he said.
Zingula gave a tour of a 17-acre field riparian buffer consisting of grass and trees that he planted 16 years ago on a farm he formerly rented. The buffer has reduced soil erosion on highly erodible land and has provided excellent wildlife habitat, although it took some work to convince his landlord it was the right thing to do, he said.
Managing crop nutrients
The tour also showed participants what farmers are doing to manage nutrients applied on cropland.
Modern hog barns keep manure from escaping into surface waters, said Jason Russell, Linn County Farm Bureau president.
"We had 18 inches of rain in June, and we did not lose any manure," he said.
Enclosed pits beneath a pair of 7,200-head finishing buildings provide manure storage for 12 to 18 months, Russell said, allowing him to apply manure when conditions are most suitable. The nutrient content of the manure is tested to determine the optimal application rates, and manure is injected into the soil to minimize odor and prevent ammonia from escaping, he said.
Farmers are also utilizing technology to optimize commercial fertilizer applications, said Ron Woeste, operations manager for Linn Co-op Oil Co. He said 80 percent of the co-op’s customers are utilizing variable rate technology to optimize fertilizer applications. Grid sampling provides a map showing applicators where fertilizer rates need to be increased or decreased, instead of applying a flat rate across an entire field.
"In the 20 years we’ve been doing this, our phosphate (application rate) is probably down 30 percent from where we were," he said.
Linn Co-op also encourages customers to use multiple, smaller nitrogen applications under its "Balanced N" program, spoon-feeding the crop as it grows while reducing the risk of unused nitrogen leaching into water. Most of the nitrogen is also applied with a stabilizer that keeps the fertilizer in a usable form longer, Woeste said.
Brian Lensch, past Linn County Farm Bureau president, explained how he uses strip tillage and cover crops to protect the environment. Lensch, who farms with his dad, Jim, switched to a strip-till system three years ago to help deal with residue in fields where they planted corn in consecutive years.
"With corn-on-corn, you have to get through the residue," he said.
The Lensches also planted a cereal rye cover crop on 500 acres last year and hope to double that acreage this year as a tool to reduce erosion and tie up nutrients that otherwise might escape.
"The name of the game is to have something green on your ground for 12 months," Jim Lensch said. "The nitrogen that we don’t use will be taken up in the root system of the cereal rye and keep the nutrients there until the corn grows. We don’t want it down the river. It’s costly to us, so we’re looking at ways to keep it on our farm."
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