China must pay attention to soil erosion problems associated with large-scale construction of infrastructure as it could threaten the security of food supply and ecological environment, an official has warned.

Zhang Xuejian with the Soil and Water Conservation Department under the Ministry of Water Resources said China could face a grave challenge if its rapid modernization continued to take a toll of land resource.

Besides natural causes, human activities -- mainly the construction of roads, railways, hydropower projects, mining and urban areas -- also led to soil erosion and the loss of water resource, Zhang was quoted as saying by People's Daily on Tuesday.

It is estimated that construction projects completed or to be finished in the 2006-2010 period would result in soil erosion in land areas totaling 15.27 million hectares.

"As things are going, large-scale human activities could cost more than the environment could sustain," Zhang said.

China lost 3.3 million hactares of farmland in the past 50 years, making the scarcity of arable land in the world's most populous country an acute challenge, according to the report.

A satellite survey of soil erosion in 2002 showed that 37 percent of the country's land areas suffered from the loss of soil due to natural and human factors.

In 2000, the soil erosion caused 400 billion yuan (US$58.8 billion) in economic losses, or 4.48 percent of the annual GDP of that year, the newspaper said, citing the Asian Development Bank figures.

Worse, 74 percent of impoverished people in China lived in areas suffering severe soil erosion.

Floods and the shortage of water supply as a result of soil erosion are also among serious consequences, Zhang said.

Although the central government's annual investment in tackling soil erosion has increased from 300 million yuan ten years ago to two to three billion yuan now, it is far from enough to guarantee projects for the prevention and treatment of the problem, Zhang said.

(Xinhua News Agency October 21, 2009)