When the NRCS revised its national standards for nutrient management this year, the agency softened its stance on the application of manure on frozen ground.
Instead of trying to mandate what occurs, the NRCS is directing its state staff to work with state soil and water-quality agencies to define the circumstances where manure can be applied during the winter.
This change would be relevant to about 25 states, mostly in the northern tier of the U.S., and state and local laws would still have the highest jurisdiction.
Some states have banned application of manure on frozen soils over concern about environmental impacts. NRCS chief Dave White says there was a fair amount of comment on this issue, and early draft revisions from his agency forbid manure application on frozen ground.
"Basically when NRCS plans animal waste facilities around AFOs or KFOs, we will plan with the producer for 180 days of storage of the manure, which should get them through the winter until the soils are thawed," White says. "However, there's a lot of states where it's already there.
"This is one we grappled with, but I think we have worked out a reasonable response. We felt the best way to approach this was on a state-specific basis. We're directing NRCS conservation sites to work with the states to develop a way to define the circumstances under which manure could be applied on frozen soils, and what conservation practices do you need with it?"
White says the revisions do have information about nitrogen indexes.
"If a state doesn't have one, we have instructions to our field staff on how to do phosphorous-risk assessments," White says.
Tips For Manure Application In Winter
For no-tillers in states that have not banned manure application on frozen ground, below are some tips from Ohio State University experts that would be good to consider.
OSU says winter application should not be part of a manure management plan, and it should only be viewed as a last resort.
· Application rates are limited to 10 wet tons/acre for solid manure more than 50% moisture and 5 wet tons for manure less than 50% moisture. For liquid manure the application rate is limited to 5,000 gallons/acre.
· Applications are to be made on land with at least 90% surface residue cover (e.g. good quality hay or pasture field, all corn grain residues remaining after harvest, all wheat residue cover remaining after harvest, well established cover crop).
· Manure shall not be applied on more than 20 contiguous acres. Each 20 acre block should be separated by a break of at least 200 feet.
· Utilize fields which are furthest from streams, ditches, waterways, surface inlets, etc. and are least likely to have manure move in a concentrated flow toward and into our water resources.
· Increase the application setback distance to a minimum of 200 feet from environmentally sensitive areas and areas of concentrated flow such as grassed waterways, surfaced drainage ditches, streams, surface inlets, and water bodies. This distance may need to be greater when local conditions warrant (e.g. – fields with more slope).
· For ODA permitted facilities and CLMs, setbacks should be 300 feet from wells and residences.
· Manure applied on frozen or snow covered ground should not exceed the nitrogen need of the next growing crop, or the crop removal rate for P2O5 for the next crop (not to exceed 250 lbs/ac), or the crop K2O needs (not to exceed 500 lbs/ac) or 10 wet tons < 50% moisture; 5 wet tons > 50% moisture; or 5,000 gallons of liquid manure per acre. Application rates are based upon the most limiting of these options.
For fields with slopes greater than 6%, manure should be applied in alternating strips 60 to 200 feet wide generally on the contour, or in the case of contour strips, on alternating strips at rates identified above. Application rates, and cover and set-back requirements also apply.