No-Till and Cereal Rye Cover Crops Key to Low Nitrate Levels? – DTN

    The Berger farm, of southeast Iowa, proves that good land and water management can be found at the tail end of a tile line.

    Last year, a statewide Iowa Soybean Association water-quality monitoring program determined that nitrate concentrations in the family farm’s tile water were 31% below average for southeast Iowa and 51% below average for the state. The water tested well below the standard for nitrates in drinking water.

    In Steve Berger’s opinion, those results are his family’s payoff for decades of no-till and cover crop practices — the cover crops were an important addition to the farm’s soil- and nutrient-management plans. Cover crops use nitrogen as they grow, diverting a nutrient that may otherwise show up in the tile water. When the cover crop dies, it releases the nitrogen back into soil through mineralization.

    Adam Kiel, state water resources manager for ISA, said Berger’s success is evident in the 14 samples he has collected for the Berger farm. “It looked like water coming out of the tap,” he said. Berger’s entire farm acreage is pattern-tiled with 35- to 60-foot laterals.

    Soil- and nutrient-management practices at the farm, based near Wellman, Iowa, suggest its conservation strategies generate both an environmental benefit and financial gain. The farm, with a 50-year history of no-till and years of rye cover crops, also produced its first 300-bushel corn yields in 2014.


    “[The soil conservation and nutrient-management work] is a short-term cost, but it has a generational payoff,” Steve said. “It is noticeable. We think we see yield enhancements.”

    The Dennis D. Berger and Son operation consists of Steve, his parents, Dennis and Janice, and Steve’s wife, Julie. The farm produces corn and soybeans in a 50/50 rotation on 2,200 acres, and is home to a farrow-to-finish swine operation. It sits in the 640-square-mile English River watershed, located in the flatlands and steep hills of the southern Iowa drift plain. Fourteen miles of terraces trace the contours of the farm’s hillsides.

    The Bergers are well-known for their conservation ethic. Steve was awarded the American Soybean Association’s 2015 National Conservation Legacy Award. In 2014, he received the Spencer Award, presented by the Leopold Center for Sustainable Agriculture. The Spencer Award recognizes farmers who strive to improve the environment.

    “[Steve] is a cover crop and sustainable-farming superstar,” said Jody Bailey, coordinator of the English River Watershed Management Authority, where Steve serves as a board member. “He’s a great resource. He can talk to other farmers in a language they can respect.”


    Steve noted that, truthfully, he knows no other way to farm. “I was brought up in it. I’ve been no-tilling my whole career,” he said. His dad, Dennis, has no-tilled the entire farm since the 1970s.

    The father and son team has not faltered in its commitment to farming without tillage and with cover crops. The Bergers manage in anticipation of challenges that may arise with their choice of practices. When their corn planters, in the days before row cleaners were available, balked in heavy crop residue, “we worked through it. We never quit,” Steve said.

    But father and son do not ignore economics. “You have to be better than average over the long term or else you’re not going to make it,” Steve said in an article published in the winter 2014 issue of the “Leopold Letter.” “We’re not going [into] this to be below average. There’s so much more to learn. I’m sure five, 10 years from now, we’ll be doing things differently.”

    For example, Steve is learning about the role of glomalin found in the soil, particularly the high levels found in heavy-residue soils, such as those in no-till and cover crop systems. Glomalin is the glue that forms clumps of soil granules called aggregates. Glomalin helps the soil resist wind and water erosion, while aiding root growth and the movement of water and nutrients.

    Cover crops do not interrupt workflow on the farm. Cereal rye is planted right behind the combine. Four to seven days before planting, the 16-inch-tall rye is sprayed with glyphosate. The result of the no-till and cover crop practices is a significant change in the soil profile, Steve believes. “You can tell you’re standing on something that hasn’t been tilled,” he said. “The fields aren’t eroded. It’s a subtle thing you see over time.”


    The Bergers added cover crops 15 years ago. “We plant 100% cereal rye behind corn and soybeans, on every acre, every year,” Steve said.

    Steve has not definitively calculated the benefit of the farm’s soil conservation practices. “I don’t know if you can put dollars and cents to it.” But some things he can see, and he believes those are indicators of good economic benefit.

    — Heavier rains of 3 to 6 inches are more commonly falling over his portion of Iowa. “The no-till fields have not shown any erosion,” he said.

    — Steve surface-applies manure from his hog operation. The soil absorbs the applications within minutes.

    — The farm is gaining organic matter — about a tenth of 1% per year. The Berger farm averages 3% to 4% organic matter.

    “After a 3-inch rain, the water runs clean off the field,” Steve says. “We’ve changed the biology of the soil.”


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