Evaluation of calcium superphosphate as an additive to reduce gas emissions from rabbit manure

Abstract

Techniques to reduce the emission of air pollutants from livestock production are demanded. In this study, the effect of an additive (calcium superphosphate) on gas emissions from rabbit manure was investigated and compared with a control where no additive was used. Calcium superphosphate was applied at a rate of 100 g/m2 per week in a manure pit during 2 cycles of growing rabbits. Manure samples were collected weekly and then chemically and microbiologically analysed. Gas emissions (ammonia, carbon dioxide, methane and nitrous oxide) were determined in 2 open flux chambers. No differences were observed in gas emissions between the treated and control samples except for ammonia emissions, which were reduced by 33% when the additive was applied (P<0.05). No statistical differences were obtained in the microbial content between control and treatment, as results showed a high variability. Dry matter content and pH were the most influential parameters on the emission of gases from manure. According to these results, the application of calcium superphosphate may be considered as an effective technique to reduce ammonia emission from rabbit manure. The additive may also be potentially effective in other species, but additional research is necessary to investigate its performance.