Abstract: 【Objective】For a long time, largely conventional tillage and burning straw cause much losses of Soil Organica Matter(SOM), which makes cropland be an emission source of Greenhouse Gas(GHG). In recent years, with no-tillage and straw returning being extended largely, as well as extensively using cropland management such as fertilizing and irrigating, organic carbon in cropland is rising again. It is supposed that cropland will be an important sink of GHG. By analyzing the change of soil organic carbon(SOC) under cropland management, carbon sequestration by cropland management in China was estimated and the character of carbon sink under cropland management in China was pointed.【Method】By reviewing lots of references and analyzing the change of SOC under cropland management in long-term experiment, we conceived cropland management scenarios. Meantime, according the areas partitioned by farming system in China, the quantity of carbon sink under cropland management was estimated and compared with the result of IPCC good practice guidance (GPG) Tier 2. Last, we used meta-analysis to estimate carbon sequestration by croplang management in China. 【Result】The total Chinese cropland carbon sink is 16.8～115.6Tg/a. It is different that SOC is influenced under different management in different area. Relationship between the annual ratio of SOC and original value in types of cropland management was analyzed. Both of them have distinct negative correlation. Saturation value of SOC is different under different managements.【Conclusion】The best management that increases SOC is using fertilizer and manure together. Next is straw returning, using manure and no-tillage. The last is using fertilizer, which even decreases the SOC. Last, We pointed the character of carbon sink under cropland management in China. Comparing with others, carbon sequestration of no-tillage, straw returning and using fertilizer and manure together is more.

Key words: China, Cropland management, Soil carbon sink, GHG, IPCC GPG, Meta-analysis