ESTIMATES OF VOLUMES AND EXPOSED SURFACE-AREAS OF STORED ANIMAL MANURES AND SLURRIES IN ENGLAND AND WALES

Estimates of animal manure (solid material) and slurry (liquid materia l) stored on farms are needed by the Ministry of Agriculture, Fisherie s & Food (MAFF) for compiling national inventories of gaseous emission s. Data needed for this purpose include the total volume and surface a rea of stored manures and slurries from different livestock species. E xisting sources of data were reviewed but have limitations in the cont ext of an emissions inventory. Suppliers of prefabricated stores were approached for numbers and sizes of stores sold since 1970. ADAS pollu tion control consultants made informed estimates of the geographic dis tribution of methods of storage in use in England & Wales for manure a nd slurry from dairy cows, other cattle and pigs. This information was combined with June 1992 census figures to provide estimates of volume s (raw and diluted) and exposed surface areas of stored manures and sl urries. ADAS livestock consultants were used to interpret census data and provide estimates of the distribution of poultry manure handling m ethods. A computer spreadsheet was used to store and process this data and is available to allow future adjustments or sensitivity analyses. In this paper, these estimates are reported on a national basis but t hey were originally gathered separately for each of 15 areas and appen ded to a report produced for MAFF. These detailed figures are availabl e on request. The majority of diluted livestock slurry is stored in ea rth-banked lagoons, with an estimated total volume of 15.5 Mm(3) and a n estimated surface area of 7.0 Mm(2). The total volume of stored soli d manure is 14.9 Mm(3) with an estimated surface area of 11.9 Mm(2) Th e estimates were compared with data from other sources and show an acc eptable level of agreement. (C) 1997 Silsoe Research Institute.