Effectiveness of different mitigation strategies to reduce nitrous oxide emissionsfrom pig manure amended soils

摘要

Developing effective mitigation strategies for reducing nitrous oxide (N_20) emissions from manured soils requires a better understanding of the microorganisms and mechanisms involved (Barton et al. 2013; Banning et al. 2015). Previous work has indicated that nitrifying microorganisms at the surface (0-10 cm) were largely responsible for N_20 emissions in Western Australian semi-arid soils and these microorganisms responded to targeted mitigation strategies for reducing N_20 (Barton etal. 2013). However, the effect of adding pig manure to these soils on the N_20 emitting microbial populations and mitigation remains largely unknown. The aim of this study was to evaluate the effectiveness of different pig manure types (stockpiled, composted and pelletised manure) and application methods (broadcast or incorporated into the soil) at reducing N_20 emissions following manure amendment. It was hypothesised that the amount of nitrified-N_20 could be reduced by a) incorporating manure at depth to avoid ammonia oxidisers in the topsoil, and b) composting or pelletising manure to decrease availability of ammonium (VanderZaag et al. 2011; Barton et al. 2013).