Act 38 Winter Manure Application Guidance

The purpose of this article is to clarify the requirements for winter manure applications for Act 38 Nutrient Management Plan (NMP) operations; CAOs, CAFOs and VAOs. Specifically the requirements apply to manure applied on the operation and to manure exported from the operation for land application on importing operations.

It should be recognized that winter application of manure is generally not a preferred practice for addressing water quality, and therefore should only be considered for use where it is a necessary practice for the operation of the farm, and where fields identified for winter manure application are situated in such a way as to minimize the potential for manure or nutrient runoff. Winter manure applications should be minimized, as much as possible, by spreading only the amount that is absolutely necessary. Winter application of solid manure can be easily avoided by stockpiling that manure during winter.

Manure application on snow or ice provides for the highest level of risk for runoff and should only be approved for unique situations that have a very low risk of runoff to a water body. Winter application fields should primarily be those with a “growing” crop. Finally, if winter application is absolutely necessary, significantly reducing the application rate for winter manure can help minimize the manure runoff potential.

All fields identified for winter application must be assessed using the most current version of the Winter Manure Application Matrix. Along with the winter matrix, Part B of the P-Index will need to be completed for any fields proposed for this practice (Version 5.0 of the NMP Spreadsheet, once released, will include “will manure be applied in winter” as one of the P-Index, Part A questions).

It is important to remember that the winter matrix is simply a guidance tool and the planner and reviewer may disagree with the results of the matrix based on specific understanding of how a particular farm site has, and is being managed. For instances where the results are questioned due to additional site specific knowledge, the results should be discussed with the SCC regional coordinator to determine if the fields are acceptable for winter application or not.

In addition to completing the winter matrix and P-Index Part B, the planner must list specific information for each winter application field in NMP Summary Notes including the 25% cover requirement, whether or not the field will be allowed to be used if it is snow or ice covered and additional setbacks to be used for added water quality protection. If at all possible, the plan notes should indicate that application will only take place at times when the ground is neither snow nor ice covered.

In addition, additional winter application setbacks will also need to be assessed for these fields.

All of the requirements outlined above apply not only to manure applied on the Act 38 operation but also to any operation that imports Act 38 manure for land application. The Nutrient Management Technical Manual, Version 9.0, NMP Summary section, page 6 states:

“Note: The Act 38 winter manure application requirements stay with the manure; independent of the final user’s animal density classification (i.e. importers of Act 38 manure that plan to spread manure in winter must develop a winter manure application matrix for each importer that plans winter applications). Importing operations should assess their fields for winter application using the same criteria that is used and explained above for CAOs and/or CAFOs”.

Nutrient Balance Sheets (NBS) completed for manure exported from an Act 38 operation must be completed using Option 3 (P-Index Part B) for any fields where winter manure applications are planned. Also, a winter matrix must be completed and submitted for any winter application fields and the NBS Summary Notes must include the appropriate winter application information outlined above.

Please see Nutrient Management Technical Manual, Version 9.0, NMP Summary section, pages 2 – 6 for additional guidance on winter manure applications. You can also contact the SCC Regional Coordinator that covers the county that you are working in.

Contact Information

Jamie Ulrich
  • Nutrient Management Program Coordinator – Central PA, State Conservation Commission
Phone: 215-287-5187