Winter Manure Application Rules Kick In Dec. 21

DES MOINES – Animal producers with totally roofed (confinement) facilities face limits on applying liquid manure starting Dec. 21 if the ground is snow-covered.

The state rules kick in then, because runoff and nutrient loss after winter manure application is more likely when manure can’t be injected into the soil or incorporated into a field.

Starting Dec. 21, liquid manure cannot be applied on snow-covered ground. These limits affect confinement facilities with liquid manure that have 500 or more animal units. Generally, 500 animal units is 1,250 finishing hogs; 5,000 nursery pigs; 500 steers, immature dairy cows or other cattle; or 357 mature dairy cows.

Except in emergencies, the law limits liquid manure application from Dec. 21 to April 1 if the ground is snow-covered with an inch or more of snow or one-half inch of ice. If manure can be properly injected or incorporated, it can be land applied during this time.

Starting Feb. 1, liquid manure application on frozen ground is restricted.

Producers must call the local DNR field office to report emergency applications before they apply.

While the law affects confinements with liquid manure, open feedlots and poultry producers can help keep manure in place by using common sense and choosing application areas far from a stream, on flat land with little snow cover.

All producers must follow setbacks from certain buildings and environmentally sensitive areas.

Search for more information on separation distances and winter manure application at Recommendations from the Iowa Manure Management Action Group about applying manure in winter are available at or