Manure applicators must recognize and respond when conditions are at high risk for runoff

We remind farmers and manure applicators to recognize and respond when conditions are at high risk for runoff when making decisions about manure storage management and applications this fall and winter. While late corn silage harvest has created situations where some manure storages may be approaching their full operational capacity, it is critical to follow the Revised Winter And Wet Weather Manure Spreading Guidance and the spreading plans in your CNMP.

You can monitor forecasts to identify days in the near term that may have conditions with lower risk using the Runoff Risk Forecast for New York State. Figure 1 shows the forecast for the next three days compared to the longer term forecast for a week out. By waiting just two or three days, some locations will go from high runoff risk to low or no risk. Be sure to check this and any local weather forecasts on the day of spreading to confirm the assumptions of the runoff forecast and actual conditions on that day.

The CAFO Permit requires that, “Farm personnel shall manage application rates and timing so as to prevent runoff from leaving crop fields during any application event,” and prohibits manure applications on saturated or frozen-saturated soils or when applied at a rate that causes the soil to become saturated at the time of that application. When winter or wet weather conditions[i] exist, manure applications must follow the revised winter and wet weather guidance which outlines the following.

. Recognizing high risk situations:

Significant rainfall or snowmelt is predicted within the next 48 hours. Concrete frost, ice layer on soil or in snowpack, deep or dense snow, or water saturated soil is present. Tile drains are flowing at least moderately from field drainage (as opposed to ground water interception).

Avoid spreading on fields with:

Past runoff problems or groundwater/well problems (see Groundwater Protection Guidelines for Agriculture). Significant surface runoff or subsurface flow that can reach a stream or ditch. An orientation toward a stream or watercourse with a slope greater than 3 to 5%. Concentrated flows are present in the field.

Implement strategies to reduce runoff risk:

Store manure until lower risk conditions return. Apply to lower risk fields (identified in your CNMP). Apply to fields with groundcover (hay fields, established cover crops). Inject or incorporate manure immediately. Increase setback distances from waterways (ditches, streams, etc.). Reduce spreading rates and/or break up applications over multiple days. Do not spread in or near areas of the fields that produce runoff (concentrated flows, grassed waterways, etc.). Monitor tile outlets during manure application.

If a CAFO finds itself in an emergency situation, the farm should discuss with their AEM certified planner other interim solutions that may be available to the farm to alleviate the emergency.

Farms that do not operate under the CAFO permit should also heed these strategies for manure management and application, as no farm is allowed to create a water quality violation as a result of a manure application.

For questions, please contact:

• The farm’s CNMP planner for help identifying low risk fields, adjusting rates and setbacks, concerns about manure storage capacity, or farm or field-specific questions.
• Kirsten Workman, PRO-DAIRY Nutrient Management & Environmental Sustainability Specialist, 607-255-4890 or kw566@cornell.edu, for technical assistance, questions about the runoff risk forecast tool or for general guidance, especially third-party manure applicators who do not work directly CNMP planners.
• Sara Latessa, NYSDEC – Division of Water, sara.latessa@dec.ny.gov for questions related to the CAFO permit.

Wet weather spreading conditions means significant precipitation (e.g., greater than 0.25 inches of rain within 24 hours when soils are approaching saturation or greater than 1 inch of rain independent of soil moisture content)  and/or snowmelt events (e.g., greater than 40°F for 6 hours or more) is forecasted within the next 48 hours.  Winter spreading conditions means soil is frozen (4”+), snow covered (4”+), or encumbered by significant surface icing. As defined by the NYSDEC CAFO General Permit (GP-0-22-001)