by Ted Funk, consulting engineer with the
Illinois Beef Association and a retired agricultural engineer at the University of Illinois
It seems that every year around this time, full manure storages and Old Man Winter team up to force a difficult choice for some livestock farmers. Where, when, and how can we apply manure safely?
The risks of nitrogen loss and phosphorus runoff are related to the amount of time between nutrient application and the crops taking up those nutrients. But the major risk in winter is gross movement of manure to surface water causing offensive conditions. “Risk” is the key word here, and we must wisely balance three risks:
- water quality impacts from field runoff, due to uncontrollable weather event(s) after manure application
- manure storages having sufficient capacity vs. overflowing from normal and/or abnormal inputs
- getting crops planted late vs. under the right conditions in springtime
Full manure storages, with no place to go, clearly put your farm in jeopardy. Even more important, earthen-embankment storages (lagoons or holding ponds) that overtop may experience catastrophic berm erosion failure, releasing large amounts of waste as a point source discharge.
As of August 2014, there are some modifications to the Illinois EPA rules governing winter application of manure. Those rules affect classes of facilities in different ways, so let’s make sure you know in which class your facility falls. First, answer these questions that affect how you can approach winter spreading of liquid manure:
1. Are you operating under an NPDES permit or considering applying for coverage?
2. Are you working with Illinois NRCS under an EQIP contract that includes the 590 Nutrient Management standard?
3. Is your single facility considered “large” under the LMFA (based on more than 1,000 animal units capacity) or are you required under the LMFA, due to owning multiple facilities in Illinois that add up to more than 1,000 animal units capacity, to have the LMFA-style waste management plan?
4. Is your facility considered a “large CAFO” under the new IEPA CAFO regulation and you want the protection of the Ag Stormwater Exemption lined out in the new rule?
Answering these questions can be difficult for some facilities, but there are fine points about winter manure spreading regulations that may change your mind about where and when to spread.
Let’s be clear about timing. The really big and nasty manure runoff events occur in late winter, because that’s when the precipitation events are typically heavier. So, if you know you will be spreading in winter, get it over with early, and do not wait until late February or early March.
If you answered “yes” to question (1), you have restrictions on winter spreading already spelled out in your permit. The new Illinois EPA rules affect new permits; existing NPDES permits operate under the older rules.
If you answered “yes” to question (2), my best advice is to confer with your local NRCS office about how to meet and maintain your obligations in the land treatment section of your Comprehensive Nutrient Management Plan as it affects your EQIP contract.
A “yes” answer to question (3) puts your facility under the set of waste management plan rules in the LMFA (900.801 et seq). Consult the LMFA rule on facility size (900.802) to determine whether that set of rules applies to you. Any size facility has to abide by the old Illinois EPA rule, Section 560 Design Criteria for Land Application of Livestock Waste, 560.206 Frozen or Snow-Covered Ground: “Waste application on frozen or snow-covered land should be avoided. If wastes are spread on frozen or snow-covered land, such application should be limited to land areas on which:
a) Land slopes are 5 percent or less, or
b) Adequate erosion control practices exist.”
That’s it. Slope of the field, erosion control practices in place.
However, if you are required by the LMFA by virtue of your facility size to have a waste management plan, the LMFA also requires that you keep records of the dates of application, the fields, and the amounts of manure applied to each field.
But here’s the caveat printed elsewhere in the regulation: even though the rules give vague restrictions about slope limits and “adequate erosion control practices,” you may still be subject to a complaint, investigation, and water quality violation notice if runoff to surface water occurs. Use common sense about where to apply, limit the rates and stay away from surface water. Prioritize fields for winter application, to reduce risk. Spread on the low-risk fields last in the season, if you need the room, and reserve some very low risk “bail-out” fields if possible.
Finally, if you answered question (4) with “yes” you now have a more extensive list of winter spreading restrictions than you did prior to the new set of rules. These restrictions don’t apply if soil conditions allow you to inject or incorporate the manure, but even then you are obliged to observe good practices according to your normal nutrient management plan. To claim the Ag Stormwater Exemption in the event of a discharge off your fields, you have to be able to show that you have taken appropriate and reasonable steps to get through the winter months without spreading manure—and that those steps just weren’t enough this year. Here are the winter restrictions (with my abbreviations) listed in Section 502.630 “Protocols to Land Apply Livestock Waste During Winter”:
- No surface application is allowed on frozen, snow- or ice-covered land unless there is no practical alternative and your storage is going to overflow otherwise.
- You must have a winter application plan in place; that plan includes your selection of available fields that meet the criteria in 502.630 c). Your list of available fields may change from year to year, depending on several factors including crop rotation.
- You have notified IEPA in writing by Dec. 1 that your storages are insufficient to carry you through 120 days.
- Surface spreading must be worked around the weather forecast. The rules are more stringent for snow or ice-covered fields than for just frozen ground.
- Setbacks are increased a lot for winter conditions.
- Monitoring fields for manure-laden discharges during melting and runoff is required, as is reporting such discharges to the Agency. See 502.630 for more details.
Dec. 1 is the implied date, after which you need special dispensation to surface apply on frozen, ice or snow-covered fields, if you operate under an NPDES permit or want the Ag Stormwater Exemption for a Large CAFO.
Anything that reduces soil erosion is usually a plus for selecting a manure application field. Extremes: surface-applied and unincorporated manure, normal rates, on a frozen HEL field that’s had corn silage removed—a formula for trouble. Injected liquid manure on a non-tile-drained, NHEL field that has lots of corn crop residue—you’re looking good. Which brings up all the discussion about vegetative buffers, vegetative fence rows, cover crops, pasture and hay field options, etc.—keep your options open when the spreading window starts to close. Tile drains could be trouble: monitor the outlets if you spread manure over tile drains. Some fields with shallow soils over bedrock, gravel, or sand should be avoided as well, and for operations with a permit, must be carefully selected.
Soil surface—snow or ice cover
If you surface apply on snow or ice, it’s reasonable to assume there won’t be any infiltration until the cover thaws—then snow or ice melt will take manure with it. The only protection you have is more distance to surface water, less slope, and more residue or crop cover. But if you can inject liquid manure into non-frozen soil beneath the surface, there is no specific prohibition against it—just the slope limit and vague erosion control guidelines. I’d suggest you carefully monitor runoff during a melt and do damage control if you find manure coming off the field.
By the way, one of the more sure ways to force your operation into the NPDES permit program is to be slipshod about spreading manure in winter. No dumping! Manure should be applied at a maximum of the “agronomic” rate of nitrogen or phosphorus, depending on the specific situation. There is no provision in the rules for “emergency over-application” of manure! If you aren’t sure of the rate you should use, don’t guess; make a phone call. And there is no excuse for operating a spreader that has not been calibrated.
Don’t spread close to, or onto, waterways. Observe common sense practices. Especially with drag hose applications doing surface application (since you don’t turn off the flow during turns), lay out the hose so that you stay well away from waterways or other conduits to surface water. Plan on leaving extra-wide setbacks if you are applying on frozen ground, especially if it is ice- or snow-covered. Be prepared to clean up releases caused during disconnecting and cleaning hoses.
Those facilities that are required by virtue of size (over 1,000 Animal Units) to have a manure management plan under the LMFA are already bound to respect the manure spreading setbacks from surface water and well heads. But those setbacks should be honored by smaller operations as well; fall and winter spreading are, if anything, more sensitive times for manure runoff, and setbacks help. Keep written records of manure storage levels as we head into winter.
IBA has retained the services of Ted Funk, a licensed professional engineer and former University of Illinois agricultural engineering professor, to visit individual farms by request of producer members. IBA will share in the cost of this confidential professional service as a membership benefit. If you are interested in learning more about Dr. Funk’s services contact that IBA at 217-787-4280.