Although the government is investing heavily in soil and water preservation, China's severe soil erosion problem is continuing to worsen.

If no tough measures were taken to tackle the problem, soil erosion would affect sustainable development and threaten the ecological safety of the country, said experts at an on-going water forum in Beijing.

Fast economic and social development requires large-scale infrastructure construction, which has affected the natural environment, said Jiang Dewen, senior engineer with the surveillance center of water and soil conservation under the Ministry of Water Resources.

The conflict between economic development and natural resources has become very pronounced in China, said Jiang at the forum to promote cooperation between China and Japan in water protection.

In the past five years, the central government invested 30 billion yuan (US$3.6 billion) in water and soil conservation. But only 50,000 mu (about 3,330 ha) of land was protected. Meanwhile, every year, nearly 10,000 mu (about 660 ha) of land suffers soil erosion.

The soil erosion caused by human activities is much harder to deal with than natural erosion and some affected land will never be recovered, said Jiang.

The key to preserve water and soil lies in prevention, said the expert. Once soil erosion occurs, the cost to harness it is much higher.

China has a large erosion affected are - 3.56 million square km- and every year, about 5 billion tons of soil is lost.

In the past, over-farming on waste land and deforestation were major causes of soil erosion. At present, soil erosion is mainly caused by large-scale construction projects, said Jiang.

A law on water and soil conservation that took effect in 1991 in China regulates that all the construction projects should make plans to preserve water and soil before they start. The project owner should be responsible for any possible soil erosion during and after the project.

At present, many big state projects have schemes to protect water and soil, including water diversion from the south to the north, the Three Gorges Project and railway building connecting west China's Qinghai Province and Tibet Autonomous Region.

However, the regulation is not well implemented in many areas as local officials do not have a strong sense of environmental protection, said Jiang.

According to a new concept of scientific development proposed by the central government recently, economic development should be in line with environmental protection. This will help change local officials' minds and urge them to devote more attention to water and soil conservation, said Jiang.

The western regions are the origins of many rivers in China and water and soil conservation there is especially important. The central government should give more policy and financial support as these areas are economically backward, said Jiang.

China has made a full set of laws and regulations on water and soil conservation and the key is to enhance people's sense of environmental protection and ensure the implementation of these laws and regulations, he said.