For some, it is already the season of snow shovelling and fuzzy mittens. For others, they are unlikely to see a snowflake anytime soon. But, for most North American farmers, we have begun to approach some semblance of winter. For some, winter implies a few months of frozen ground. For others, winter is cold and wet, but with little snow and only a short period of frozen ground. But for farmers all over, many want to know when they can – and can’t – spread manure.

This varies by jurisdiction, and can be a complicated question to answer at times.

For one thing, all states also have different definitions of “winter,” most of which extend beyond the typical definition of “Dec. 21 to March 20.” Many states define winter by whether or not the ground is frozen, consecutive days of snowfall, days below a certain temperature, etc.

Exceptions, exemptions and other caveats can also apply depending on location, the size of the farm, the existence of a nutrient management plan, etc. In the interest of helping landowners understand their winter manure options better, Manure Manager has prepared a guide. In order to ensure information stays correct and relevant in the long-term, this guide is not a list of states or provinces where spreading is banned but rather is a guide on understanding the nuances of winter spreading regulations.

This article is meant for informational purposes only and should not be relied upon to determine legal obligations.

What is defined as ‘winter?’ Well, it’s complicated.

If you were to ask most adults (at least in the northern hemisphere), “when is winter?” they would probably tell you it’s Dec. 21 to March 20. However, interestingly, if you were to ask a young child “when is winter?” they might answer something to the degree of “when there’s snow on the ground.” As such, children in some parts of North America might think of Nov. 15 as “winter” more readily than they’d think of March 17 as winter. And while those children would be technically wrong, they’re not the only ones with a more fluid definition of winter.

In the context of manure and/or manure application, few states and provinces define winter as Dec. 21 to March 20. For example, in the context of spreading, Alabama defines winter as Nov. 15 to Feb. 15.

Some jurisdictions rely solely on ground, temperature and/or precipitation conditions. For example, in Arkansas, as of 2015, land application of waste, including manure, cannot be undertaken when soil is saturated, frozen or covered with ice or snow. It also cannot occur when “significant precipitation” is anticipated within the next 24 hours.

Other jurisdictions might use a combination of dates and conditions. For example, in Ontario, for spreading, winter is defined anytime soil is frozen or snow-covered, or as Dec. 1 to March 31 regardless of whether or not soil is frozen/snow-covered. Delaware’s ban applies from Dec. 7 to Feb. 17, but beyond that timeframe, applying nitrogen or phosphorus fertilizers is prohibited on frozen or snow-covered ground.

Even “snow-covered” can differ in its definition between jurisdictions. For example, Wisconsin defines “snow-covered” as one inch or more of snow, whereas Ontario defines snow-covered soil as soil with a layer of snow on the surface with “an average minimum depth of five centimeters.” Frozen soil is defined as any five centimeter layer of frozen moisture in the top 15 centimeters of soil.

Bans, exemptions and recommendations

Not all states or provinces have hard bans on spreading; some, such as Ontario, define winter manure application as “inappropriate” or “not recommended.” States with broad bans include: Delaware, Maine, Maryland and Vermont. More states, such as Massachusetts, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin, have restrictions on spreading but would not be accurately characterized as outright banning the practice.

Even some states and provinces with hard bans have exemptions and variance provisions meant to accommodate extraordinary circumstances such as extreme weather events (such as the 2021 December rainstorms in British Columbia, after which a ban was temporarily lifted to decrease the risk of pits spilling over) or economic hardship. However, in many or most cases, exemptions and variances require prior approval and thorough demonstration of necessity.

Some restrictions also vary depending on the size of the farm and whether or not the farm as a nutrient management plan. For example, in Wisconsin, large, permitted farms (CAFOs) are not allowed to spread on frozen or snow-covered ground. Smaller farms under nutrient management plans follow the Wisconsin Nutrient Management Plan 590 Standard. However, not all smaller farms have nutrient management plans. Some counties, such as Brown County, require winter manure spreading plans for all farms.

In Minnesota, winter spreading is restricted for permitted facilities, usually sites with 1,000 animal units are more. However, some sites may have permits for other reasons.

Regulations can also differ in different parts of states. Since NRCS Code 590 for Alabama was changed in 2002, winter application for North Alabama is now a “consideration” more than a hard and fast rule – where plants are actively growing and expected to be able to take up the nutrients applied, winter application may be permitted (however, this must be justified in a nutrient management plan).

When in doubt

Remember, good manure management principles are always relevant. Common restrictions, such as the minimum distance between manure stockpiles/temporary storage and a body of water or distances between stockpiles and slopes apply year-round. For more information on temporary manure storage regulations, see our recent feature.

If you are unsure of winter spreading regulations, restrictions or bans in your area, contact local officials, consult your state’s agriculture department website and work with your local Extension office to get the latest information and ensure proper understanding.

• Tweet

• Net farm income down for 2024, livestock strong: USDA
• Funding: $7Million for climate-smart dairy farmers