IA DNR: Manure application on frozen ground may lead to unintended consequences

DES MOINES – While it is not recommended, winter manure application is sometimes necessary due to limited storage or unanticipated weather or facility conditions.

“Animal producers know the value of lost nutrients, especially with fertilizer costs soaring, but they may not know the risks of winter application,” said Dan Olson, an environmental specialist at the Atlantic DNR field office.

Applying manure from now until the ground thaws will be extremely risky. It could result in manure flowing over land or through tile lines into streams. It also results in phosphorus washing away, instead of binding to the soil as it does in warmer weather.

Olson urges producers to watch weather and field conditions carefully and to keep a wary eye on levels in the manure storage structures. That can help them avoid applying at the worst possible time.

Producers should contact the local DNR field office to discuss viable alternatives if storage is filling up. If field conditions are bad, they may need to consider alternatives such as pumping to another pit or transferring manure to another site.

“If you end up applying, look for high flat areas located a long way from surface waters,” he said. “Stay away from tile lines near the soil surface and tile inlets.” The DNR recommends applying only on fields with slopes of four percent or less and where soil erosion controls are in place.

“Some producers may think that if you follow DNR recommendations or abide by required separation distances it will keep you out of trouble,” he said. “But the fact that you observed the setback does not guarantee manure won’t reach a stream. If it does, the producer could face a penalty for causing a water quality violation or possibly a fish kill.”

Olson added that, for open lot producers, manure can really get moving during periodic late winter thaws.

“With fertilizer costs up and supplies tight, producers will want to take full advantage of these nutrients and avoid causing water quality problems or fish kills,” Olson concluded.

More information is available on the Iowa Manure Management Action Group’s Web site at http://www.agronext.iastate.edu/immag/pubs/imms/vol3.pdf

Writer: Karen Grimes