Winter spreading can be beneficial for farmers, providing time for application on cropland and reducing the risk of soil compaction by heavy equipment. However, winter application is discouraged & under increased public scrutiny and carries an increased risk of polluting groundwater or surface water. The biggest risk is when spread on snow-covered or frozen fields and within 72 hours of a significant rainfall or snowmelt event.
Follow this 6-point winter manure management strategy:
- Provincial regulations restrict/limit the spreading of manure during winter months. In Alberta for instance, spreading on frozen or snow-covered ground is prohibited (AOPA) unless special permission is received. In Manitoba restrictions on the application of nutrients came into effect on November 10th.
- Which fields could benefit most from nutrients in manure? Often it becomes easiest to apply manure to fields closest to manure storage, but farmers should seek to optimize return to the value of manure by using the 4R principles. The Prairie provinces produced a manure best management guide for producers: Tri-Provincial manure Application and use Guideline. Ontario Guidelines on Winter application
- Assess the risk of ground & surface water for all fields being considered for application. Provincial resources and agronomy specialist can help assess varies soil factors the pose greatest risk to water runoff or groundwater contamination. Prioritize fields with living cover or those with crop residue cover.
- What is the runoff/ groundwater risk potential based on soil moisture, snow accumulation and melt, and weather forecast?
- Determine safe rates of manure application. It is best if you can get a soil sample before spreading manure. Collect a representative sample of your manure from storage as it is being applied. A manure analysis will provide both the total nutrient content and nutrients available to the next crop.
- Have a contingency plan in case weather conditions change and contamination event occurs or risk is high. Provincial nutrient management regulations provide good guidelines as to things that should be included in your plan like the Ontario NMP Contingency planning
Bottom line is to avoid winter manure spreading if possible, have a strategy, have a good understanding of the benefits and risks, test your manure and soils regularly.
Talk to one of our specialists to get started on soil sampling and field mapping or for additional resources.