Spatial and Temporal Trends in Atmospheric Sulphur Deposition to Agricultural Surfaces in the United Kingdom

Keywords: Sulphur, Deposition, Agricultural surfaces.

Sulphur dioxide is emitted whenever sulphur-containing fossil fuels are burnt. Per capita sulphur dioxide emissions to air in the United Kingdom are among the largest in western Europe and, although some 80-90% of this sulphur is transported overseas, the remainder deposited within our boundaries currently contributes between 5 and 25 kg S /ha/yr to surface soils and vegetation. While this input of sulphur leads to acidification of poorly buffered upland catchments, it provides necessary nutrients to agricultural soils where acidification is not a problem. UK sulphur dioxide emissions have already halved since the peak around 1970 and will continue to fall further as we implement the changes necessary to meet our international treaty obligations. S inputs to land from the atmosphere have decreased by at least this amount. Over much of the agricultural area of the UK, direct absorption of sulphur dioxide by crops and soils was the major sulphur deposition route but sulphur dioxide concentrations have declined faster than total UK emissions, especially in England where rural concentrations of sulphur dioxide are now some 10% of what was measured 20-30 years ago. Wet deposition inputs have also decreased, but by a factor similar to that for total emissions. By 2010, total S inputs in the UK will have declined further to between 5 and 10 kg S /ha/yr.

G W Campbell, AEA Technology, Culham Laboratory, Abingdon, UK

R I Smith, Institute of Terrestrial Ecology, Penicuik, Scotland

24 pages, 9 figures, 16 refs.