Geoscience Reference
In-Depth Information
pollution of ground water is thought to date back to the wide-scale ploughing up of
grassland during and after World War II.
Water drains more quickly when the rock is fissured; thus nitrate levels are much
higher in aquifer water underlying the Lincolnshire Limestone, for instance, than in
most chalk aquifers. However, it is predicted that even the levels in the limestone wa-
ters will rise further as stored nitrate is flushed from the finely porous stone.
F
IG. 63
Gully erosion in a field sown with oil-seed rape, Penrith. (Photograph by R. Evans.)
E
ROSION
In 1982, representatives from eight EEC countries met in Florence to discuss soil
erosion and conservation. In surveying the problem, D. W. Sanders of the Food and
Agriculture Organisation stated that “large areas of the world's agricultural land are
now suffering from severe erosion and related forms of land degradation. It is estim-
ated that between 5 and 7 million hectares of land are lost annually through soil de-
gradation. This must be stopped if the world is to retain the potential to feed future
populations.”
The figures may change but the message has remained the same since G. V. Jacks
and R. O. Whyte wrote
The Rape of the Earth
in 1939. We are used to hearing about
soil erosion in the Third World and in the U.S.A. but, unless we have seen an affec-
ted area, dry statistics do not evoke strong images or emotions. In Britain, we tend
to think of erosion as something affecting Cat Bells in the Lake District, or Mam Tor
