A new state law kicks in Dec. 21, limiting the land application of liquid manure on snow-covered ground to emergency situations.

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.

“However, all livestock and poultry producers need to protect water at all costs,” said Gene Tinker, DNR coordinator of animal feeding operations. “All producers must prevent pollution as they land apply manure.”

The law limits liquid application from Dec. 21 to April 1 if the ground is snow-covered. If manure can be injected or incorporated, there is no limit on land application 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.

“Under those conditions, producers can only apply 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,” said Tinker. “They need to notify the regional DNR field office before they apply, and they can only apply to fields that are identified for emergency application in their manure management plans and have a Phosphorus Index of 2 or less.”

Tinker also said that because they are surface applying, 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 should 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,” Tinker said. “If there are tile intakes downgradient of the application area, they must temporarily block the intake – PVC pipe sleeves are the most common method.”

They must report emergency applications starting Dec. 21 to the local DNR field office. If they have questions about a specific site or risks, they can also contact a DNR field specialist. Field office locations and phone numbers are available at www.iowadnr.gov/fo/index.html.

Starting Feb. 1, confinement producers with 500 or more animal units will also be limited to emergencies if applying liquid manure on frozen ground. Producers can read the law at http://coolice.legis.state.ia.us/Cool-ICE/default.asp?Category=billinfo&Service=Billbook&menu=false&hbill=SF432.

More information on the protected areas is available at www.iowadnr.gov/afo/landapp.html. Recommendations from the Iowa Manure Management Action Group about applying manure in winter are available at www.agronext.iastate.edu/immag/pubs/imms/vol3.pdf.

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