AGRICULTURAL C CYCLE AND GREENHOUSE-GAS EMISSION IN CHINA

This paper assesses the production, consumption and store of organic c arbon in the agricultural system, including all products from agricult ure, of China. An estimation showed that about 90% of carbon uptake by agricultural systems would be emitted or returned to the atmosphere b y several types from 1990 to 2000, others remain in durable agricultur al products and soil. Even though the fixation rate is getting lower, generally speaking Chinese agriculture is a ''sink'' but not a ''sourc e'' in respect to the atmospheric CO2 and CH4 concentrations in both t he current period and that after few decades. China's Soil stores 12% of the whole soil carbon in the World. Considering the different globa l warming potentials (GWP), an approach to the country budgets of CO2 and CH4 has been presented based on the measurements in rice paddies a nd in the Tibet and Inner Mongolia grasslands.