Cold Weather Kicks in Limits on Winter Manure Application for Confinement
Posted: 01/26/2012
DES MOINES – Most producers recognize that winter manure application can result in loss of important nutrients and cause runoff problems.

State law, however, actually prohibits some producers from applying liquid manure on snow-covered ground after Dec. 21 and frozen ground after Feb. 1 unless it’s an emergency.

The law does not apply to manure from open feedlots or dry manure.

It applies to confinement (totally roofed) facilities with liquid manure that have 500 or more animal units. Generally, 500 animal units would be 1,250 finishing hogs; 5,000 nursery pigs; 500 steers, immature dairy cows or other cattle; or 357 mature dairy cows.
“We’ve been lucky this year having very little snow on the ground,” said Ken Hessenius, supervisor of the DNR Spencer field office. “But now that we have a little snow, we want to remind all livestock and poultry producers that they need to protect water and prevent pollution as they land apply manure.”

In addition, the law limits liquid manure application from confinements from Dec. 21 to April 1 if the ground is snow-covered. If manure can be injected or incorporated, it can be land applied during this time. Snow-covered ground is defined as soil having one inch or more of snow cover or one-half inch or more of ice cover. Starting Feb. 1, confinement producers with 500 or more animal units will also be limited to emergencies if applying liquid manure on frozen ground.

Under those conditions, producers can apply only in emergency situations, defined in the law as unforeseen circumstances beyond the control of the producer such as natural disaster, unusual weather conditions, or equipment or structural failure.

Confinement producers must call the local DNR field office before they apply to report emergency applications. They can apply manure only to fields identified for emergency application in their manure management plans that have a Phosphorus Index of 2 or less. DNR field specialists will ask several questions about the application area and amount. They may have ideas or suggestions for producers who have questions about a specific site or risks. Field office locations and phone numbers are available at .

Hessenius added that if the manure is surface applied, producers and commercial applicators need to observe the separation distances, generally applying at least:
•    750 feet from buildings such as residences, businesses and schools;
•    200 feet from environmentally sensitive areas such as a drinking water well, lakes, rivers, streams or ag drainage wells; and
•    800 feet from high quality water resources.

“The research shows that the later in the season and the closer to spring snowmelt that you apply, the greater the risk that manure-laden runoff will reach a stream,” he said. He recommends that producers who might run out of storage this winter consider emergency application early in the winter, not late.

“Most important, they should use good common sense, applying on flat land with the least snow cover, located far from a stream,” Hessenius said.

More information on the protected areas is available at:

Recommendations from the Iowa Manure Management Action Group about applying manure in winter are available at