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Talking tillage, runoff and cover crops

By Staff | Jul 30, 2010

A commercial crop duster from Webster City simulates with smoke how aerial seeding of cover crops can be performed this fall during Tuesday’s field day near Otho.

OTHO – While 130 people enjoyed pork loin sandwiches in the shade of a large tent, a crop duster dropped low to spray smoke to simulate aerial seeding of spring rye.

The appreciative crowd applauded after three passes and the plane receded to the east. The onlookers were at the end of a 2.5-hour field day at the Smeltzer Trust and Demonstration Farm in Otho – an afternoon devoted to discussing the advantages of reduced tillage methods, using cover crops after harvesting and methods for controlling field runoff.

Cover crops

The big emphasis, said co-organizer Karen Hansen, Webster County naturalist, was on cover crops and how it can help hold nitrogen in the soil. Farming lighter on the land with reduced tillage was another emphasis. “We’re just planting seeds in people’s minds,” Hansen said.

Thomas Kaspar, of the National Laboratory for Agriculture and the Environment, said that, for farmers, the take-home point of cover crops, primarily small cereal grains, is that in fields under corn and soybean rotations, “there are several months without plants growing on them.

Dave Nelson, kneeling, demonstrates the impact on the soil in an 8-inch wide strip-tilled row. Nelson is a tenant on the Smeltzer Trust and Demonstration Farm in Otho, which hosted a field day Tuesday on reduced tillage, cover crop usage and controlling field runoff.

“Cover crops take up water, nitrogen and phosphorus and help protect the soil. Plus, they add organic matter (in the soil profile) and encourage earthworms.”

Sarah Carlson, who is conducting 33 cover crop trails in Iowa for Practical Farmers of Iowa and helped present the workshop, agreed. “We’re presenting the research and practical knowledge of cover crops.

“It’s a viable option for farming operations.”

Reduced tillage

Dave Nelson, a tenant on the Smeltzer farm, and co-owner of Brokaw Supply in Fort Dodge, discussed the benefits in soil tilth with reduced tillage methods, as well as more profitability with reduced trips across the field each growing season.

Denis Schulte, Webster County soil and water conservationist, holds one of three jars of water containing soil from virgin prairie that had never been tilled. He shows how even with swirling the soil in water, it maintained its structure. The other jars contained soil from a conventionally tilled field and a third from a field under no-till practices for five years.

Nelson said his row crop yields are similar than before using strip-till, but they are earning income due to using less fuel, fewer inputs and reduced labor.

He was partnered with Denis Schulte, district conservationist for the National Resource and Conservation Service, who produced three jars of water with soil in the bottom on each jar. He explained that one jar contained soil from a field under conventional tillage, another with soil from a field under no-till practice for five years and a one from virgin prairie which has never been tilled.

The conventionally-tilled soil structure broke down quickly when the water was swirled. The no-tilled soil held its shape better and the third did not break down.

“Every time we till,” Schulte said, “we break down the soil’s ability to drain water. Tillage is necessary sometimes if it fits the need.

“But if we can demonstrate that it’s not always necessary, why do it?”

Schulte also outlined federal programs that will help some producers switch to reduced tillage practices. Nelson said that these programs were helping him to pay for his strip-tillage equipment.

Controlling runoff

Bruce Atherton, a drainage engineer for the NRCS, outlined drainage patterns that would not only drain flooded fields, but control the flow to help prevent or slow flooding downstream.

He also discussed the farm’s underground anaerobic bioreactor, which is a low-tech method for taking out nitrates from field runoff. The underground device simply diverts tilled water through the reactor. Wood chips absorb the water, slowing the flow and allowing microbes to digest nitrates, releasing harmless nitrogen gas into the air, rather than into local watersheds.

He was joined by Carolyn Schwartz, a Greene County soil conservation technician, who discussed how her county dredged 12 oxbow wetlands along Cedar Creek and East Buttrick Creek in her county.

She said that field tiles were diverted into the wetlands which also captured the nitrates, encouraging beneficial plant growth. She said the number of Topeka shiners, small endangered minnows that are native to Greene County, has been flourishing since the enhancements two years ago.

“A lot of hard work went into planning the field day, said co-organizer Jim Patton, Iowa State University Region 7 Extension director. The farm held a strip-till field day two years ago.

“We probably won’t do this every year,” Patton said, “but we feel (that these field days) honor Ann Smeltzer’s values.” The Smeltzer Trust includes eight farms, including five in Webster County.

The Webster County Pork Producers provided grilled pork loins as part of a catered meal.

Contact Larry Kershner at (515) 573-2141 or at kersh@farm-news.com

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