STUDY ON EVOLUTION OF ORGANIC CARBON STOCK IN AGRICULTURAL SOILS OF CHINA: FACING THE CHALLENGE OF GLOBAL CHANGE AND FOOD SECURITY

China is facing the great pressure under the Kyoto Protocol in reducing the rapid increasing emission of CO_(2 )resulted from the rapid industrialization. This paper deals with the issue of the study on status and dynamics of organic carbon stock of agricultural soils of China. China agriculture is meantime facing the double challenge of stabling the food production under the shortage of arable lands with decreasing soil productivity and of enhancing the C sink for mitigating the increasing CO_(2) emission. The general poor storage of organic carbon and the apparent significance in crop productivity in the arable soils of China offers a great potential and, however, an urgent need for C sequestration agriculture in China. The evolution of C stock of the agricultural soils in the last two decades and the possible sink effect, the overall C sequestration potential and the feasible rate should be taken into account in the issues of priority researches. The authors strongly suggest that a C sequestration strategy, a win-win strategy, and technology should be developed after well-done investigations of soil C sequestration and put into practice in croplands of China in the early 21~(th) century to meet the commitment to the Kyoto Protocol. Soil C sequestration links concerns of global change and food security for sustainable development of agriculture of China and buys China opportunity for control the fast increasing CO_(2) emission due to the rapid industrialization. Priority of research should be put to the following issues of soil C sequestration: (1) the overall C stock of China cropland soils and the changing dynamics with the agricultural development at various scales; (2) features of C cycling in cropland soils with land fragmentation, and under intensified agriculture and high chemical inputs; (3) coupling mechanisms of soil C sequestration and productivity enhancement for different farming systems for sustainable agriculture in the future.