A late harvest plus an early freeze equals a headache for winter manure management. The Cornell University PRODAIRY program; NYS Department of Agriculture and Markets; NYS Department of Environmental Conservation (DEC); and USDA-Natural Resources Conservation Service recently issued the following bulletin to New York dairy farmers:
Whether your farm is a CAFO or not, it is important to take stock of manure storage capacity: at current fill rates, know how long before the storage will reach maximum fill level, and have a plan in place to avoid a situation of overtopping. CAFO farms should reach out to their planner to review emergency and winter/wet weather spreading plans.
Farms who are concerned about storage levels but do not have a CAFO planner should reach out to Soil and Water Conservation or Natural Resources Conservation Service staff to get help with identifying lower risk fields and other practices to reduce risk of runoff when having to spread to avoid overtopping.
Although the goal is always to avoid spreading when conditions are poor, it’s important to be prepared in case your back is against the wall with extended wet field conditions and storage that is at risk of overtopping.
For CAFO’s, emergency spreading to avoid an overflow must be communicated to DEC either through a written incident report or in the Annual Compliance Report. If, during emergency spreading, maximum application rates identified in the permit are exceeded, DEC must be notified within 24 hours followed by a written incident report in 5 business days. Additionally, storages that overflow MUST be evaluated for structural integrity and re-certified by a Professional Engineer (PE). A PE evaluation after an overflow is a smart safety practice for all other farms. For making field application decisions, farmer knowledge of safe fields is critical.
During winter weather conditions, defined as more than 4 inches of snow or 4 inches of frost in the soil, CAFO farms must follow the Winter and Wet Weather Manure Application Guidelines, and it is recommended that CAFOs follow these same guidelines during wet conditions. The document provides useful guidance for non-CAFO’s as well.
Penn State University Extension also has published a list of “Do’s and Don’ts of Winter Manure Spreading.” Author Charles White says guidelines apply to farms operating under a Manure Management Plan, which are typically smaller, less intensive operations. They include:
- Do maintain a setback of 100’ from streams, lakes, ponds, sinkholes, drinking water wells, and aboveground inlets to agricultural drainage systems. The reductions in manure spreading setbacks around streams, lakes, and ponds that are allowed in other seasons by implementing best management practices do not apply during the winter.
- Don’t spread on slopes greater than 15%. These would be soils listed with “D” or “E” codes on a soil survey map.
- Do limit winter application rates to less than or equal to the following: 5,000 gallons/acre of liquid manure; 20 tons/acre of solid non-poultry manure; 3 tons/acre of solid poultry manure. Alternatively, you can use a nutrient balance sheet to determine the phosphorus balance rate of manure for the next crop and apply equal to or less than that rate.
- Don’t spread on fields with less than 25% crop residue cover unless a cover crop has been planted there. Corn silage and low yielding soybean fields typically have less than 25% residue cover during the winter.
- Do prioritize winter spreading on fields with living plant cover, such as cover crops, hay fields, or pastures. The living plants in these fields will do a better job preventing nutrient losses during winter by taking up nitrogen into plant biomass and more effectively preventing erosion.
- Do list the fields that will receive winter manure applications in the “Winter Application Worksheet” of your Manure Management Plan. Also make a note of the fields that will receive winter spreading on your farm map and indicate the slopes in those fields.
“Larger, Concentrated Animal Operations (CAOs) that are regulated under Act 38 or permitted Concentrated Animal Feeding Operations (CAFOs) should consult their Nutrient Management Plan to determine allowable winter spreading practices,” advises White.
White’s recommendations, including Manure Management Plans, are based on Pennsylvania regulation. Guidelines and regulations for applying manure in the winter may vary among state NRCS jurisdictions.
Although USDA-NRCS provides criteria for legal winter manure application, it should be viewed as an emergency exemption, not a standard practice. Winter application should not be a routine element in a farm’s manure management plan. If you are faced with the unavoidable necessity of winter application, it is best to contact your local NRCS officials in advance to develop a legal application plan.