Compared effects of long-term pig slurry applications and mineral fertilization on soil denitrification and its end products (N sub(2)O, N sub(2))

The long-term (9 years) effect of pig slurry applications vs mineral fertilization on denitrifying activity, N sub(2)O production and soil organic carbon (C) (extractable C, microbial biomass C and total organic C) was compared at three soil depths of adjacent plots. The denitrifying activities were measured on undisturbed soil cores and on sieved soil samples with acetylene method to estimate denitrification rates under field or potential conditions. Pig slurry applications had a moderate impact on the C pools. Total organic C was increased by +6.5% and microbial biomass C by greater than or equal to 25%. The potential denitrifying activity on soil suspension was stimulated (x1.8, P