More than one-third of China's vast territory is crumbling, according to statistics from the Ministry of Water Resources.

Up to 3.56 million square kilometers of the country's landmass is already affected by serious erosion, while about 4.5 billion tons of soil (19.2 percent of the world's total) is being lost every year.

Not only is black soil in northeast China losing its fertility, other areas have also suffered soil erosion, with extreme cases including the deadly mudslides last August in Zhouqu, Gansu Province.

Annually, the Yellow River takes away about 1.6 billion tons of earth from the northwestern Loess Plateau (a large area that includes Gansu), 400 million tons of which deposit at the lower reaches.

As a result, the bed of the lower Yellow River is about 5 meters higher than that of the land outside its dikes, creating what is called "a hanging river". In Kaifeng, a city in Henan province, the riverbed is about 12 meters higher than street level, posing a serious threat to the safety of residents.

The Yangtze River also takes away 2.4 billion tons of soil every year, resulting in similar problems.

Ecologists say that such soil losses can contribute to deterioration in a river's water quality due to the pesticides and chemical fertilizers contained in the soil.

The Xinjiang Uygur and Inner Mongolia autonomous regions, as well as other northwestern provinces, also suffer severe wind erosion and desertification as a result of their dry climates. Sandstorms originating in these regions can affect areas thousands of kilometers away.

The Qinghai-Tibet Plateau is also affected by erosion caused by constant freezing and thawing.

In southwest China's red soil region -- largely Guizhou and Yunnan provinces -- heavy rainfall, especially torrential rains, easily flushes away the thin layer of red earth on the rolling hills. Due to the red soil region's lack of arable land, farmers have to exploit every area, which in turn leads to more deforestation and makes erosion even worse.

Apart from natural, geographic and climate conditions, human activities like the construction of roads, railways, hydropower projects, mining, over-farming and over-grazing also take their toll on the land.

Eco-degradation is also interrelated with poverty, according to official statistics, which show that about 74 percent of poverty-stricken residents live in areas that suffer severe water and soil erosion.

(China Daily September 28, 2010)