Winter manure application has negative environmental impacts like nutrient runoff leading to eutrophication. Some states have banned winter spreading between specific dates, but bans have limitations and don't consider field/weather conditions. Alternative approaches focus on evaluating field conditions prior to spreading to minimize runoff risks. Future regulations may combine limited late-winter bans with field evaluation tools to balance environmental protection and farm needs.

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Relevant Issues and State Specific Regulations for Winter Manure Application
Janina R. W. Kavetsky
ANS 418: Animal Agriculture and the Environment
Michigan State University Fall 2016
December 9, 2016

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Spreading of manure onto winter fields (especially when frozen or snow covered) has
long been a contentious practice in many parts of the United States. Within many states,
agricultural authorities have sought to curb this practice, primarily in hopes of minimizing
associated negative outcomes. Despite this, many established regulations have built in
exceptions, and in states without such rules, winter spreading may be a common practice. The
purpose of this paper is to: analyze negative impacts of this practice, spotlight established bans
and potential outcomes of such bans, highlight how other parts of the country have developed
alternative means to deal with this issue, and finally speculate on possibilities for future control
measures.
Numerous research studies have been conducted that establish a link between winter
manure spreading and negative environmental impacts. According to Randy Pepin in his article,
What’s the Big Deal with Winter Spreading of Manure?, these negative impacts are the result of
nutrients such as nitrogen and phosphorus being introduced into waterways (2013). When excess
phosphorus enters water bodies, it can result in eutrophication (rapid plant growth). When the
excess plants die it causes water hypoxia (low oxygen), which decreases the ability for water
plants and animals to survive (Pepin, 2013). Under normal circumstances, phosphorus will stay
in the ground attached to soil particles. However, in the case of erosion or frozen impervious
ground (where phosphorus remains on soil surface) this nutrient is carried in water runoff (from
snowmelt or precipitation) along with soil into nearest bodies of water. Nitrogen on the other
hand is mainly lost in the atmosphere as ammonia (NH4) in a process known as volatilization.
Nonetheless, many organic manure compounds are both contributors to eutrophication and are
water soluble, meaning they are subject runoff from spring thaw or rain events (Pepin, 2013)

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In a University of Vermont study, researchers found that winter dairy manure application
resulted in runoff concentrations of nitrogen and phosphorus that was 2-15 times greater than
those from summer applications (Meals, 2005). In light of evidence such as this, many feel that
manure spreading should be banned for negative impacts to environment alone. However, this is
only part of the picture; such practices can also have major economic and social implications.
For example- following a 2005 winter in Wisconsin, improperly land applied manure ended up
wiping out 10 years and $2 million worth of restoration works in one watershed, and causing
contamination of private drinking water wells (Meals, 2005).
Looking at things from the farmer’s perspective however, winter spreading is a logical
and necessary practice. Many farms may need to spread in the winter because they have
limitations of storage facilities. Updating storage on farms can be both costly and difficult,
especially if there are nearby residences that could limit placement options for such structures.
Additionally, winter spreading makes sense for farmers as it allows farmer to limit amount of
time devoted to spreading in the spring, which for many farmers is considered one of the busiest
time of the year (Bogovich, 2011).
Despite the inherent complexity of this issue, many states resort to one-size-fits-all
solutions, namely the use of winter manure spreading bans. The oldest of these bans was
established in Vermont in 1995 (Kling, 2013). The state of Vermont bans winter manure
application between December 15 and April 1.Vermont’s ban exists as part of their Accepted
Agricultural Practices (AAPs), and requires farmers to store all manure produced during the
period (107 days) or be able to stack all manure in a way that will not lead to water quality
impacts (discharge). Additionally, the AAPs require the stacking site to be greater than 100 feet
from private wells, property lines, surface water, or land that is subject to annual overflow from

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adjacent waters (Kling, 2013). While all farmers are expected to comply with these regulations,
exemptions may be granted by the secretary of agriculture in emergencies such as failure of
waste storage facilities.
The second oldest state ban was established in Maine in 2001(Kling, 2013). Though less
comprehensive in its requirements, Maine also focuses its spreading prohibition based on time
period (December 1- March 15) (Maine Department of Agriculture). While outright exemptions
do not exist in this state, farmers may apply for ban variances and receive leeway concerning
spreading dates based on the discretion of commission. Variances for this spreading ban are only
granted in case of emergency, and must be made verbally to commissioner or designee followed
by written request within 10 days of verbal request. The variance issued does not entirely let the
farmer off the hook for compliance but, the commission has discretion as to changing the start
date of ban for that specific farmer.
The most recent manure spreading bans were enacted in Pennsylvania (2011) and
Maryland (2013). The ban in Maryland is similar to the ones in Maine and Vermont, where the
ban is centered on spreading prohibition based on calendar dates (November 1 or 15-March 1)
(Kobel, 2016). Like the previous bans the Maryland restriction does have built in exemptions in
case of emergency. The provisions in Pennsylvania on the other hand, base spreading
recommendations on field conditions. Under this regulation spreading is prohibited unless the
field has a 100’ setback from environmentally sensitive areas, if on high slope fields and on
fields without adequate residue or cover crops (Kling, 2013).
When looking over the different states which are employing bans to manage winter
manure spreading, the question one must ask is, what has been the outcome of these regulations?
While the intention of these regulations was to limit the occurrence of discharges, to prove a

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reduction in negative impacts, there is a need for cohesive data pointing to what outcomes were
produced following ban implementation. Wisconsin Discovery Farms conducted one of the first
on-farm evaluation projects to identify the risks of manure application in the late winter period
(Radatz, Cooley and Frame, 2013). Close evaluation of the data indicates that spreading during
early winter (November-January) is much different than spreading in late winter when the frost
extends deeper and is more solid. Further, this project showed that manure applied during
February and March have increased risk of running off and contributing to high nutrient losses
into surface water. Additionally, they found that total bans, increase volume of manure that must
be stored and can increase the risk of runoff during spreading in the spring (Radatz, Cooley and
Frame, 2013).
Based on the findings of the Wisconsin Discovery Farms study, researchers proposed that
a more reasonable approach would be to manage spreading based on field conditions rather than
rigid prohibitions based on calendar dates (Radatz, Cooley and Frame, 2013). Bans based on
calendar date alone do not take into account climactic variations, or individual field
characteristics. For example- there are times when applying early in winter is optimal because
lack of snow and/or frost affords the opportunity for manure to come in contact with the soil.
Along this same line of reasoning, not allowing farmers to begin fieldwork based on calendar
dates can increase risk of runoff or discharge because the window for application is narrower and
potential for runoff from saturated soils and spring rains is greater. Despite this, the study did
illustrate the need for some caution concerning time of year when application occurs. This study
found that around 90% of annual runoff in Wisconsin occurs between December and June. While
runoff between December and March most often occurs from snowmelt or rain on frozen ground,

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simply avoiding application in February and March could reduce total nutrient loss, since 50% of
annual runoff occurs between these two months (Radatz, Cooley and Frame, 2013).
Overall though, because of the complexity of this issue, one-size-fits all legislation often
fails to meet the needs of all those which may be affected by impacts of winter application.
Rather, future legislation would be more effective when employing multiple tactics to minimize
negative spreading impacts. While a strict ban prohibiting spreading starting in November or
December may not be advantageous, because of the increased risk of runoff in February and
March, if a ban must exist, it would be better applied to late winter rather than fall or early
winter. However, a ban alone would likely not be sufficient as it does not address field
conditions or climactic variation in a given season. Therefore a truly comprehensive policy
would have to include standards or means of evaluating field conditions on the day of
application.
Encouragingly enough, not all states resort to bans alone to control winter spreading.
Michigan for example, has chosen to circumvent a ban, and alternatively encouraged farmers to
use an evaluation tool, the Manure Application Risk Index (MARI) to determine if field
conditions are adequate for winter manure spreading. By using this tool before manure
application, farmers are also protected from nuisance complaints under Right to Farm legislation
(ANS 418, 2016). While accordance to MARI recommendations is not mandatory, it allows
farmers protection under Right to Farm should their spreading practices be called into question.
Some states are looking at implementing evaluation tools such as MARI in their own states, but
whether or not they will tie such tools to legislative measures remains to be seen. Despite future
legislative measures however, winter manure spreading is likely to remain a complex and
contentious issue well into the future.

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References
Bogovich, W. (2011. February). Regulations.gov- Comment on Proposed Changes to National
Handbook. Retrieved December 3, 2016 from,
https://www.regulations.gov/document?D=NRCS-2011-0001-0119.
Kling, C. (2013). Iowa State University- State Level Efforts to Regulate Agricultural Sources of
Water Quality Impairment. Retrieved December 3, 2016 ,
http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1026&context=econ_las_pubs.
Kobel, R (2016, July). Bay Journal- Hogan Administration Eyes Relaxing Maryland Farm
Pollution Regulation. Retrieved December 3, 2016 from,
http://www.bayjournal.com/article/hogan_administration_eyes_relaxing_maryland_farm_polluti
on_regulation.
Maine Department of Agriculture, Conservation and Forestry. Nutrient Management Rules.
Retrieved December 3, 2016 from,www.maine.gov/sos/cec/rules/01/001/001c565.doc
Meals, D. (2005, November). CTIC Partners - Research Shows Winter Application of Manure is
a Bad Idea. Retrieved December 03, 2016, from
http://email.ctic.purdue.edu/partners/112005/rnt.asp
Pepin, R. (2013, December). What's the big deal with winter spreading of manure? Retrieved
December 03, 2016, from https://www.extension.umn.edu/agriculture/dairy/manure/whats-the-
big-deal-with-winter-spreading-of-manure/
Radatz, A., E. Cooley, D. Frame (2013, November). UW Discovery Farms- Will Spreading Bans
Reduce Manure Runoff Events? Retrieved December 3. 2016 from,
http://articles.extension.org/pages/67684/will-spreading-bans-reduce-manure-runoff-events.