Emissions of CH4, N2O, NH3 and odorants from pig slurry during winter and summer storage

Manure storage contributes significantly to greenhouse gas (GHG), NH 3 and odour emissions from intensive livestock production. A pilot-scale facility with eight 6.5-m 3 slurry storage units was used to quantify emissions of CH 4 , N 2 O, NH 3 , and odorants from pig slurry during winter and summer storage. Pig slurry was stored with or without a straw crust, and with or without interception of precipitation, i.e., four treatments, in two randomized blocks. Emissions of total reduced S (mainly H 2 S) and p -cresol, but not skatole, were reduced by the straw crust. Total GHG emissions were 0.01–0.02 kg CO 2 eq m −3 day −1 during a 45-day winter storage, and 1.1–1.3 kg CO 2 eq m −3 day −1 during a 58-day summer storage period independent of storage conditions; the GHG balance was dominated by CH 4 emissions. Nitrous oxide emissions occurred only during summer storage where, apparently, emissions were related to the water balance of the surface crust. An N 2 O emission factor for slurry storage with a straw crust was estimated at 0.002–0.004. There was no evidence for a reduction of CH 4 emissions with a crust. Current Intergovernmental Panel on Climate Change recommendations for N 2 O and CH 4 emission factors are discussed.