Effect of Adding Alum or Zeolite to Dairy Slurry on Ammonia Volatilization and Chemical Composition
The research paper by A. M. Lefcourt and J. J. Meisinger, published in the Journal of Dairy Science, investigates the effectiveness of two amendments—alum and zeolite—in reducing ammonia emissions and altering the chemical composition of dairy slurry. As dairy farming expands, the challenge of managing manure effectively has intensified, particularly concerning nitrogen loss through ammonia volatilization and excess phosphorus levels.
The study involved measuring ammonia emissions and chemical changes in dairy slurry treated with varying concentrations of alum (0.4%, 1.0%, 2.5%, and 6.25%) and zeolite over a 96-hour period. The researchers utilized small wind tunnels to assess ammonia volatilization and analyzed manure samples for total nitrogen, phosphorus, and other chemical parameters.
Results indicated that the addition of 6.25% zeolite and 2.5% alum significantly reduced ammonia emissions by nearly 50% and 60%, respectively. Alum worked by lowering the slurry pH to below 5, effectively retaining ammonia, while zeolite acted as a cation exchange medium, adsorbing ammonium and reducing dissolved ammonia gas. Both amendments also decreased soluble phosphorus levels, with alum eliminating it almost entirely.
The study highlighted the importance of careful alum application to avoid excessive soluble aluminum levels, which could pose environmental risks. The findings suggest that both alum and zeolite can serve as viable on-farm amendments to mitigate ammonia emissions and manage phosphorus in dairy slurry, contributing to more sustainable dairy farming practices.
This research paper is significant in the field of agricultural science, particularly in manure management and environmental sustainability. It addresses critical issues related to nutrient management in dairy farming, where the balance of nitrogen and phosphorus is essential for both crop productivity and environmental protection. The research contributes to ongoing discussions about effective strategies for reducing ammonia emissions, which have implications for air quality and public health.
By demonstrating the effectiveness of alum and zeolite as amendments, the study provides practical solutions for dairy farmers facing regulatory pressures and environmental challenges. The findings can inform best management practices and encourage the adoption of cost-effective treatments that enhance nutrient retention in manure, ultimately benefiting both agricultural productivity and environmental health.
