Reduction of ammonia emissions by applying a urease inhibitor in fattening pig houses
Ammonia emissions have a negative impact on the environment due to acidification and eutrophication. In Germany, more than 92% of emissions come from agricultural production. European efforts are underway to regulate ammonia emissions. One measure to reduce ammonia emissions is the use of a urease inhibitor, which inhibits the enzyme urease and thus prevents the hydrolysis of urea, which in turn leads to a reduction in ammonia emissions. The inhibitor's potential to reduce ammonia emissions has already been demonstrated in cattle farming. In this study, the first structured investigations were carried out on the use of a urease inhibitor to reduce ammonia emissions in three mechanically ventilated fattening pig houses with fully slatted pens and under-floor slurry storage. In addition to ammonia concentrations, the gas concentrations of carbon dioxide, methane and nitrous oxide and odour emissions were measured. The reduction effect was calculated using four different calculation approaches based on the case-control principle: a linear mixed model, the direct case-control approach, the case-control in time approach and a novel developed ratio-difference approach. It was demonstrated that a daily application with an inhibitor application rate of 50 mg m-2 and application liquid of 0.15 litres m-2 could be recommended. A reduction in ammonia emissions of 22% was demonstrated. The effect of the inhibitor on the other emissions – carbon dioxide, methane and odour – was also investigated. Neither an increase nor a reduction was observed. No effect could be analysed for nitrous oxide, as the FTIR measuring technique used was not suitable for the very low nitrous oxide concentrations. The results of this study show that the use of a urease inhibitor in fattening pig houses is a suitable mitigation measure for reducing ammonia emissions.
urease inhibitor, ammonia mitigation, gaseous emissions, pig fattening, calculation approaches
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