Progress in effects of biochar on organic carbon and microorganism in soil

Biochar is a solid carbonaceous residue made by burning biomass under oxygen-deficient conditions. Biochar plays a key role in biogeochemical cycles of soil organic carbon and integrated microorganism. The effects of biochar amendment on organic carbon and microorganism in soil are highly influenced by properties and application rate of biochar as well as environmental conditions of soil. Several authors observed a large increase in stability of soil organic carbon and decrease in mineralization rate of soil organic carbon in biochar amendment treatment，which indicated biochar application favors carbon sequestration. However，some results suggested that biochar application increased microbial biomass and stimulated microbial activity，in turn increased mineralization rate of soil organic carbon. This paper summarized the previous studies about the effects of biochar addition on decomposition of soil nature organic carbon，activity and stability of soil organic carbon，soil aggregate and its stability，biomass and activity of soil microorganism，and soil microbial community structure. Based on the previous studies and the remained questions，the following prospects in this field were proposed： improving the comprehensive study on environmental benefit and risk after biochar application