MITIGATING GREENHOUSE GAS EMISSIONS THROUGH CONTINUOUS ACIDIFICATION OF CATTLE SLURRY

The agricultural sector is a major contributor to global greenhouse gas (GHG) emissions, particularly through livestock activities such as enteric fermentation and manure management. These processes release methane (CH₄) and ammonia (NH₃), which contribute to climate change, atmospheric pollution, soil acidification, and water quality deterioration. In Malaysia, livestock production remains a significant source of GHG emissions, with 1,247.65 Gg CO₂-equivalent CH₄ emissions from enteric fermentation and 287.84 Gg CO₂-equivalent CH₄ from manure management reported in 2022, alongside 108.7 Gg CO₂-equivalent nitrous oxide (N₂O) emissions from livestock manure. Despite growing concerns about the environmental impacts of livestock production, the adoption of effective emission mitigation technologies in Malaysia has been limited due to financial constraints, technical requirements, and the dominance of profit-oriented production systems. Many globally recognized mitigation strategies, including dietary modifications, feed additives, and advanced manure management systems, remain costly or impractical for small- and medium-scale livestock operations. Slurry acidification has emerged as a promising and relatively cost-effective approach for reducing emissions from livestock manure. This technique involves lowering the pH of cattle slurry using chemical or biological acids, thereby inhibiting microbial processes responsible for methane and ammonia production. Previous studies have demonstrated that slurry acidification can reduce CH₄ emissions by 67–87% and NH₃ emissions by 50–88% during storage and land application, while also helping to control odors and reduce the overall environmental impact of manure management. However, most existing research has been conducted in temperate regions, leaving uncertainties regarding its effectiveness under tropical climatic conditions. Malaysia’s high ambient temperatures and potentially higher organic matter content in livestock manure may influence microbial activity and alter the efficiency of acidification processes. Therefore, exploring the applicability and performance of slurry acidification in tropical livestock systems is essential. This study examines the potential of continuous cattle slurry acidification as a strategy for reducing greenhouse gas emissions under Malaysian conditions, contributing to the development of practical and sustainable manure management practices in the country’s livestock sector.