Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Methane emissions from animal wastes under different environmental conditions - CC0209

Anaerobic biological activity in excreta from farm animals is a potentially significant source of atmospheric methane. Previous estimates of methane emissions have been of limited accuracy, due to a lack of data specifying emissions from manures deposited on pastures by grazing animals. The overall objective of this study is to improve the reliability and accuracy of such estimates. The project will aim to determine the effects of various environmental factors on the specific methane emission rates from manures of the most numerous classes of extensively reared farm livestock, and to investigate changes in emission rates that occur with time, following manure depletion. The work will take place under controlled environmental conditions, using a novel odours and emissions chamber that enables air to be circulated at velocities between 0.2 and 5.6 m/s across the surfaces of emission sources. Air and emission source temperatures can be controlled to within a range of 12 to 25C. Methane accumulation will be monitored in an enclosed volume of circulating air over a period of time sufficient for the establishment of equilibrium. Measurements of methane concentration in air as a function of time will allow calculation of specific methane emission rates and mass transfer coefficients. The results of the study, together with field measurements obtained in another project (CSA 2302), will be included in a mathematical model to estimate the effects of environmental factors and experimental error on the accuracy of a national methane inventory. Experimental data from the study may also be used to challenge or support assumptions made in the evaluation of methane conversion factors.
Time-Scale and Cost
From: 1993

To: 1995

Cost: £49,639
Contractor / Funded Organisations
Silsoe Research Institute (BBSRC)
Fields of Study
Agriculture and Climate Change