The South Downs are turning white and barren, threatening to end 5,000 years of farming, a report has warned.

A 25-year study by Oxford University's Environmental Change Institute has found erosion is causing serious damage to the Downs.

Soil is being turned thin and stony by erosion, accelerated by floods and modern farming methods.

Dr John Boardman, who headed the research, believes farming has become almost unviable and could disappear completely without urgent action.

He said: "The main issue in southern Britain is the impact it is having on communities in terms of flooding and also pollution of rivers in the wet autumns and thunderstorms in summer.

"Also, there's a longer-term issue of losing the soil and the ability to grow crops. Current farming systems clearly are unsustainable."

His research found persistent flooding during the Eighties and Nineties severely damaged fields of winter cereals.

"Muddy floods", carrying water, silt and pollution from fertilisers, have caused serious problems, with one property flooded 31 times in one winter.

The report, published in the respected periodical, Transactions of the Institute of British Geographers, states the soil on the Downs used to be at least one metre and up to four metres deep.

Now it is between 15cm and 25cm deep on most hill slopes.

Dr Boardman found more farmers were planting winter cereals such as wheat during the autumn.

This meant the plants had little time to take hold before the heaviest downpours between September and November.

He said: "Soil conservation measures have been negligible and flood protection has consisted mainly of engineering works and limited land-use change at sites where property damage has occurred."

He called for measures such as decreasing the stoniness of soils and providing better economic incentives for arable farming in marginal areas.

The National Farmers' Union said it was aware of problems and was considering what improvements could be made.

Tuesday September 2, 2003