Methane emissions from Danish cattle dung pats in the field

Abstract

The emission of methane from stored cattle manure has been intensively studied in recent years, whereas little information is available on the release of CH4 from dung pats in pastures. The total emission of CH4 from 1 kg cattle dung pats in a Danish pasture was therefore measured in late summer 1992 and 1993 and in the spring and early summer of 1993. Closed chambers (31 headspace) were used, with corrections for non-linearity of CH4 accumulation as a function of time and for daily variation in the release of CH4. CH4 release from fresh 1 kg pats began immediately and ceased after 10-18 d. Total emissions ranged from 37 (late summer 93) to 170 (spring 93) ml CH4 per dung pat. The total release of CH4, estimated on the basis of these values, from the dung pats produced by a cow during the grazing season in Denmark is only 0.8-4% of the emission likely to result from the same dung production stored as liquid manure during the same period.