This article is more than 11 years old

This article is more than 11 years old

Almost 100 million people in south-west China will lose the land they live on within 35 years if soil erosion continues at its current rate, a nationwide survey has found.

Crops and water supplies are suffering serious damage as earth is washed and blown away across a third of the country, according to the largest study for 60 years. Harvests in the north-east, known as China's breadbasket, will fall 40% within half a century on current trends, even as the 1.3 billion population continues to grow.

While experts said farming and forestry were the main causes of the problem in more than a third of the area affected, the research team said erosion was damaging industrial areas and cities as well as remote rural land.

About 4.5bn tonnes of soil are scoured away each year, at an estimated cost of 200bn yuan (£20bn) in this decade alone.

The poor will be worst hit, warns the report from China's bio-environment security research team, with almost three-quarters living in erosion-hit areas.

The country's 80,000 reservoirs are also affected, with sand and mud reducing their storage capacity each year. Like soil deposits along rivers, that increases the risk of flooding.

"If we don't conduct effective measures, erosion will cause major damage to social and economic development," Chen Lei, director of the ministry of water resources, told the official People's Daily.

Professor Mu Xingming of the Institute of Soil and Water Conservation told the Guardian that overpopulation was largely to blame.