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ILCC’s farm hosts cover crops event

By Staff | Sep 10, 2010

John Sawyer, an Iowa State University professor of agronomy, speaks to a group of farmers Aug. 26 at a cover crop field day held at Iowa Lakes Community College’s farm near Emmetsburg. Sawyer, and a handful of other speakers, addressed how cover crops work to reduce soil and chemical runoff and can have positive effects on cash crops planted in spring.


Farm News staff writer

EMMETSBURG – With fall tillage decisions now just weeks from implementation an estimated 80-plus farmers, agriculture students and others gathered at Iowa Lakes Community College’s college farm near Emmetsburg Aug. 26 for an update on options for soil- and water-friendly management.

“One of the reasons cover crops are gaining popularity in Washington is because they are in field. They contribute to the nutrient cycle, reduce erosion and add organic matter to the soil,” said Jeremy Singer of the National Laboratory for Agriculture and the Environment. “Tests have shown they give us a 13 to 60 percent reduction in nitrate runoff and there is reason to believe that lower number was a result of test environment as much as the cover crop.”

Singer and several other speakers representing the Iowa Learning Farm, Natural Resource Conservation Service and Iowa State University offered further insight and practical knowledge on planting post harvest cover.

The practice, which is gaining popularity in more eastern states like Illinois and Ohio is loosely divided into two strategies, planting winter-hearty crops, like rye and wheat, or non-wintering plants like oats, radishes or triticale.

Some cover crops are viable for aerial seeding into standing crops, to germinate after harvest, or producing vegetation which break up soil and reduce compaction. Others, like the experimental “tillage radish,” produce vegetation which break up soil and reduce compaction then break down and restore their nutrients to the soil.

Non-wintering cover crops die off naturally before spring, while hearty crops must be sprayed or tilled under prior to planting. Cash crop yields have proved more difficult to maintain for corn acres, but the experts agreed the risk can be minimized by making good use of available information.

“Cover crops, in our research, had little to no effect on soybean yield,” Singer said. “In corn, ideally for best yields, you want to wait about a week after killing that cover crop before planting. Selection of crop species is important.

“In our tests there was as much as 25 bushel difference between the worst and best cover crops.”

Singer also said that adding additional nitrogen before the cash crop often aids in the breaking down the cover material and making resources available for the cash crop.

A more universal problem with winter hearty crops is that wet conditions can affect timetables for applying crops in the fall or killing them again in spring. Singer said that this problem had only hindered test fields once in five years of ongoing cover crop research.

Several farmers expressed interest in the details of a current Natural Resource and Conservation Service program to reimburse farmers up to three consecutive years for planting cover crops.

The program sets several conditions for planting and disposing of cover crops, but offers up to $60 per acre for cover crops planted on traditionally managed acres and as much as $110 per acre for organic farms.

“We go out and try things on some real acres, so we can help farmers out with some of those tricky decisions,” said Sarah Carlson with Practical Farmers of Iowa. “The money is available. There are lots of options and it only costs $23 an acre to plant a cover crop you do it very cheaply.”

Contact Kevin Stillman at kw.stillman@gmail.com.

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