China's conversion of farmlands to forests and grasslands has contributed more than 4 percent to the growth of global green areas, according to a release from the National Forestry and Grassland Administration published on Friday.

Since 1999, China has launched two projects returning 14.2 million hectares of farmland to forests and grasslands, with the central government investing more than 570 billion yuan ($84 billion) to the cause, the administration said.

Soil erosion treatment in the middle and upper reaches of the Yangtze River and the Yellow River has also improved, as has desertification in the northern regions and rocky desertification in the southwestern areas.

Millions of farmers and herdsmen from 25 provinces, autonomous regions and municipalities have participated in and benefited from the project.