Simple Management Changes Drastically Reduce Pig House Methane Emission in Combined Experimental and Modeling Study

Area of Science:

• Environmental Science
• Agricultural Science
• Climate Change Mitigation

Background:

• Livestock slurry management is a significant source of greenhouse gas emissions, particularly methane.
• Reducing methane from animal agriculture is crucial for global warming mitigation efforts.
• Slurry retention time and temperature influence microbial activity and methane production.

Purpose of the Study:

• To evaluate the effectiveness of frequent slurry removal strategies in reducing methane and ammonia emissions from pig houses.
• To assess the impact of these strategies on overall emissions, including potential increases from outside storage.
• To provide recommendations for optimizing slurry management to minimize greenhouse gas impact.

Main Methods:

• Conducted a year-round continuous measurement campaign in pig houses.
• Implemented and tested three distinct frequent slurry removal strategies: slurry funnels, slurry trays, and weekly flushing.
• Utilized an extended anaerobic biodegradation model (ABM) fitted and validated with barn measurements to predict storage emissions.

Main Results:

• Slurry funnels, slurry trays, and weekly flushing reduced methane emissions by 89%, 81%, and 53%, respectively.
• Slurry funnels and slurry trays demonstrated a 25-30% reduction in ammonia emissions.
• Model predictions indicated a risk of negating barn methane reductions due to increased emissions from outside storage.

Conclusions:

• Frequent slurry removal from pig houses is an effective strategy for reducing methane and ammonia emissions.
• Combining slurry removal with pre-storage anaerobic digestion or storage mitigation technologies (e.g., acidification) is recommended to maximize emission reductions.
• Even without storage mitigation, a net methane reduction of at least 30% is achievable across all tested removal strategies.