亚洲精品久久久久久一区二区_99re热久久这里只有精品34_久久免费高清视频_一区二区三区不卡在线视频

Scientists warn that rock desertification has become the no.1 ecological disaster in southwest China and that it is urgent to take steps to control it.

The area of rock desertification is expanding at an annual 2500 square kilometers and is restricting social and economic development in southwest China.

Rock desertification and desertification are the two extreme forms of the worsening of the eco-environment. Due to serious destruction of the surface vegetation and soil erosion, soil degrades and the base rock emerges where no grass may grow. By the end of 2001, the area of rock desertification in 284 counties in Yunnan, Guizhou, Sichuan, Chongqing, Guangxi and western Hunan has come to more than 100,000 square kilometers with an annual economic loss exceeding tens of billions of yuan.

Rock desertification gives rise to rapid worsening of local eco-environment. In southwest China areas where rock desertification is a scourge the forest coverage is mostly lower than 15 percent. Under the impact of rock desertification in its environs, the waterfalls in Huangguoshu in Guizhou has extended its annual dry season from two months in the 1980s to five months now and sometimes even dries up. Rock desertification hit 80-90 percent of the land in the more than 3000 square kilometer heartland of Mashan in Guizhou where forest coverage used to amount to 60-80%. More than 100,000 people find it difficult to live and will have to be resettled.

Rock desertification has seriously hit the economic growth in southwest China. Due to the serious destruction of vegetation, the small regional climate becomes foul. In the last few years, the incidence of natural disasters has jumped from one in eight or nine years to one in two or three years with an annual economic loss of more than 400 million yuan in Guangxi where rock desertification is serious.

Rock desertification has brought a loss of 2.8 billion yuan (US$338 million) to 77 counties in Guizhou whose annual per-capita GDP accounts for one third of the national average. Of the 48 poverty-stricken counties, 39 are in rock desertification-stricken areas. There are more three million poverty-stricken people and the rate of the people who return to poverty is high.

Rock desertification causes the serious loss of soil and water, endangering the navigational safety in the Pearl River and the Yangtze River. The amount of the sand flown into the Yangtze, the Pearl River and their tributaries from rock desertification-stricken areas in southwest China is nearly five times the average eroded soil in eastern China.

Guizhou where rock desertification is the most serious suffers the loss of soil and water in 80,000 square kilometers and sends annually 270 million cubic meters of sand into the Yangtze River and the Pearl River, posing serious dangers to the electric power stations in the lower reaches.

The sedimentation of sand in the last five years at the Wujiangdu Power Station on the Wujiang River, a major tributary of the Yangtze, is ten times the designed amount. Sand from rock desertification are now posing serious dangers to Longtan and Dahua power stations on the Hongshui River, a tributary of the Pearl River.

The normal operations of these power stations have direct bearing on the implementation of the national project of sending electricity in the west to the east as well as on the ecological safety and economic and social stability in Guangxi, Gguangdong, Hong Kong and Macao.

Scientists appeal that northwest China must be aware of the fact that rock desertification has become its no.1 ecological disaster and that it is necessary to make large-scale rock desertification control and the rebuilding of a benign eco-environment as an important part of the efforts to open China's west.

They suggest that the governments at all levels and scientific research institutes have to do a good job of planning for the large-scale control. The plans should be unified and biological, engineering and management steps should be organically combined to form a multiple layer and highly effective comprehensive system.

They said that the rock desertification control should be integrated with efforts to help peasants get rid of poverty and ask them to give up crop farming and return to bamboo, grass or fruit farming wherever it is ecologically necessary and also be combined with tourism.

They say that it is necessary to give up crop farming and return to forestry and cultivate forestry by setting mountains off limit to human activities. Excessive logging and all acts detrimental to ecological vegetation must be forbidden in an all-round way in southwest China.

Electricity, natural gas and coal should be used instead of firewood as the cooking fuel. All means should be employed to protect and rejuvenate vegetation and build southwest China into China's biggest green resource bank, a tropical fruit base and an ecological tourist garden to contain the spread of rock desertification.

They say that it is imperative to enact relevant laws and decrees and preferential policies for rock desertification control. The rock desertified hill slopes should be allocated free of charge to all those units or individuals who are willing to invest in the control and no changes will be made in the coming 30 or 50 years.

They suggest that preferences in taxation and capital support will be given. A new mechanism for the long-term investment in land with the eco-agriculture as the mainstay will be established and new industries for in-depth development of ecological products will be developed to quicken the pace in rock desertification control and ecological building.

(www.cenews.com.cn September 9, 2002)