17.11.2014

Sound manure management

With the exception of grazing systems where the animals excrete directly onto the pasture, livestock production generally requires some form of manure management (e.g. storage and removal/application to land), which provides further risk of nutrient loss and GHG emissions. Simple storage methods such as compacting and covering solid excreta can reduce N2O emissions by up to 90 per cent as well as NH3 emissions (that can then cause offsite GHG emissions) by up to 30 per cent (Chadwick, 2005), while reducing the surface area:volume ratio of the slurry storage pits or capping the pits will also reduce emissions. Further, manure can be used as an energy source through its use in biogas plants and the controlled conversion to CH4, although care must be taken to ensure that no leakages occur as this may even increase total GHG emissions (Bruun et al., 2014). Finally, the manure (or slurry from the biogas plant) can be used as fertiliser, reducing the need for external inputs (e.g.