As the world's largest agricultural nation, China has great potential to cut greenhouse gas emissions (GHG) through the application of a Clean Development Mechanism (CDM), experts said.

During a two-day seminar that ended on Tuesday, experts majoring in sustainable agriculture and climate change discussed the feasibility of CDM projects in two agricultural areas, including rural household biogas and conservation tillage.

China is the biggest seller in the CDM market, with 701 projects having been registered with the CDM executive board by Jan 19, 2010, according to statistics from the National Development and Reform Commission.

Currently, most registered projects are related to small-scale waterpower, industrial energy efficiency and renewable energy development. Only a few concern agriculture and forestry, which are actually major anthropogenic sources of greenhouse gas emission in the country.

Dong Hongmin, deputy director at the Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agriculture Sciences, said the biogas CDM project has great potential to control greenhouse gas emissions and to increase farmers' incomes.

Dong developed China's first household biogas digesters project in Enshi, a poverty-stricken city in Central China's Hubei province, which was approved by executive board as a successful CDM project in 2009.

"As a CDM project lasts for 10 years, it is expected to bring 60 million yuan ($8.79 million) to 33,000 farmers. Each farmer will earn 182 yuan a year from the project," she said.

At present, 195 million households are suitable for developing biogas digesters in China.

However, since a biogas digester usually costs between 4,200 to 5,000 yuan, less than 20 percent of these families can afford installations, Dong said.

Some 5 million rural household biogas digesters will be built this year, with the total number of households with biogas expected to reach 40 million by the end of the year, according to a plan announced by the Ministry of Agriculture on May 6.

Conservation tillage, an innovative method that employs no tillage and leaves the remains of crops in the soil to reduce the effect of wind and water erosion, was another sector discussed by experts for its enormous control of CO2 emission.

Professor Li Hongwen of the Conservation Tillage Research Center of the Ministry of Agriculture, estimated that a hectare of farmland could have a CO2 emission reduction around 300 kg.

"If only 10 percent of farmlands in North China can employ conservation tillage, the annual reduction of CO2 emissions will reach up to 2 million tons."