Ningxia Hui Autonomous Region, an arid area in northwest China, has reported marked reduction of mud and sand washed into the Yellow River, thanks to soil and land conservation efforts over the past years.

Photo taken on September 17, 2008 shows the Yellow River, dubbed the "mother river" of China, flows through Ningxia Hui Autonomous Region, an arid area in northwest China. [Xinhua]

Ningxia had harnessed soil erosion over an area of 19,500 square kilometers, or 40 percent of the region's total, as of the end of last year, and mud and sand washed into the Yellow River had been reduced by 40 million tons annually since 2003, said an official with local water resources department on Thursday.

"The regional government spent more than 4 million yuan (about US$590,000) on average each year to harness soil erosion," said Zhang Ning, an official with soil and water conservation bureau of the regional Water Resources Department.

He said the investments were used to build new dikes, reinforce existing dikes and plant trees along the river.

The areas along the middle and upper reaches of the Yellow River suffer the most serious soil erosion in the world, with a total eroded area of 454,000 square kilometers. The average amount of mud and sand washed into the river every year reaches 1.6 billion tons.

Beginning in 2003, China planned to pour a total of 83 billion yuan into tackling soil erosion along the Yellow River by constructing more than 160,000 dams.

"Greater efforts are still needed to plant trees and grass in areas along the river to reduce the amount of mud and sand washed into the Yellow River as arid weather has worsened the soil erosion situation," said Li Shengbao, vice-president of Ningxia Academy of Agriculture and Forestry Sciences.

Li is a director of a program, which focuses on studying techniques to restore ecological system in Semiarid Loess Hilly Area. Under the program, a 2,000-hectare experimental base will be set up in Penyang county of Ningxia.

"We hope that the program will help the forestation rate in the experimental area stay at 50 percent or above," said Li.

Ningxia has already invested 45 million yuan so far this year to combat soil erosion.

"We believe water in the Yellow River will become more clear in the future," Zhang said.

With a mainstream of 5,464 km, the Yellow River, dubbed the "mother river" of China, originates from Qinghai Province, flows eastward through Sichuan and Gansu provinces, Ningxia Hui and Inner Mongolia autonomous regions, and Shaanxi, Shanxi and Henan provinces before emptying into the Bohai Sea from Shandong Province in east China.