Freezing temperatures following a wet fall and delayed harvest make this year’s manure application challenging. For many in northwest and north central Iowa, surface application has been the only viable option during the last few weeks.
Add to that, on Dec. 21 the limitation on applying liquid manure from confinements on snow-covered ground kicks in. Confinement sites are totally roofed facilities with more than 500 animal units, e.g., 1,250 finishers, 500 cattle, etc.
Ken Hessenius, supervisor of the Spencer DNR field office, recaps requirements to keep producers on the right side of Iowa’s manure application rules. All producers must follow some setbacks for surface application.
1. Snow-covered and frozen ground restrictions apply to application of liquid manure from confinements unless the liquid manure is injected or incorporated on the application date. They do not apply to small animal feeding operations (confinements with 500 or less animal units).
2. If you must switch from injection or incorporation to surface application:
- Call the local DNR field office to notify them you need to do emergency application.
- Update the current manure management plan and apply only on fields identified in the MMP.
- Cover or block any tile intakes downgradient of the application area. The temporary intake blocks must be in place prior to land application and for at least two weeks following it.
- Follow separation distance requirements for surface application. When surface applying liquid manure, a 750-foot setback is required from residences, other buildings and public use areas. For liquid and dry manure, a 200-foot setbackis required when surface applying near most environmentally sensitive areas such as wells, sinkholes and water sources. Finally, high quality water resources need additional protection and have an 800-foot setback for surface application.
3. Check your construction permit to see if your facility claimed points on the Master Matrix for injecting or incorporating manure. If covered by item 26e on the Master Matrix (footnote c), your operation must have a written waiver from a DNR field office before surface applying.
4. Check to see if you have a similar nutrient management plan under a federal NPDES permit or NRCS plan, and make sure it allows for surface application.
“Many producers are in a bind because of the weather this year,” Hessenius said. “One option is to surface apply just enough to get by until the weather breaks in the spring and manure storage can be emptied.”
To prevent surface application runoff during freeze/thaw cycles, Hessenius recommends picking the most appropriate fields:
- Flat or gently sloping
- Far from a stream or other water source
- Less vulnerable areas away from environmentally sensitive areas like wells, sinkholes or ag drainage wells.
And, remember to plug those tile intakes.
Find out more from a previous DNR news release or check out the latest Iowa Manure Management Action Group’s (IMMAG) update for 10 things to consider when winter manure application is necessary.