The researchers blamed farming and the clearing of forests for much of the damage. Rural areas are not the only ones losing soil. Land is also being affected in cities and near mines and factories.

The researchers say that every year, four and one-half billion tons of soil are washed or blown away. At that rate, they say, grain production in northeastern China could decrease forty percent within forty to fifty years. The country depends on that area for grain; the northeast is often called China's breadbasket.

The research team estimates that erosion has cost China at least twenty-nine billion dollars in economic losses since two thousand. The team also says that seventy percent of China's poor live in areas damaged by soil loss.

Xinhua, the official news agency, reported that the team said China is in a worse situation than many other countries suffering from soil erosion. These include India, Japan, the United States and Australia.

Land sometimes becomes desert and can no longer support plants. This process is called desertification. A study published earlier this year suggested that climate change has been a major cause of this in China. The paper appeared in Earth-Science Reviews in June.

Scientists say more than ninety percent of grasslands in northern China have decreased in quality as a result of desertification. Dried lakes in the north produce most of the dust that affects life for people in cities like Beijing and Tianjin.

Still another problem for China has been flooding along the Yangtze River. Widespread flooding took place in the late nineteen nineties. After that, the government limited tree cutting along the sides of mountains near the river.

And that’s the VOA Special English Agriculture Report, written by Jerilyn Watson. Archives of our reports are at voaspecialenglish.com. I'm Jim Tedder.