Manure storage practices in Canada: farm survey analysis with implications for GHG emissions

Manure storage systems enable farmers to apply nutrients at the right time for crop production but are also a source of greenhouse gases. This study analyzed Canadian Farm Management Surveys (conducted in 2017 and 2021) to quantify the prevalence of manure management systems and use of mitigation practices and identify changes over time. The surveys represented the beef, dairy, poultry, and swine sectors fairly well with some exceptions (e.g., underrepresentation of swine in western Canada). Results show a shift towards liquid manure in the dairy sector and dominance of liquid manure in the swine sector and solid manure in beef and poultry sectors. Practices that may reduce emissions include mechanical separation, which gained popularity in the BC dairy sector. A stable minority (10%) of farmers use additives for their manure in some provinces. Anaerobic digestion remains rare (∼1% in the dairy sector and less in other sectors). For solid manure, storage for >6 months (many >1 year) was common. Adoption of solid manure active composting was modest at 5%–10%. These baseline data show there is a high potential for further adoption of beneficial management practices that decrease emissions.