It is unclear the mechanisms of nitrogen deposition to carbon sequestration and depletion in terrestrial ecosystem where restricted by nitrogen

especially lack of understanding on processes of soil organic carbon input

transformation and output.In this paper

newly research advances on the influence of extrinsic nitrogen(such as nitrogen deposition and adding nitrogen) on decomposition of litter and turnover of soil organic matter fractions are discussed.In addition

the different responses of soil respiration components(such as root respiration

microbial respiration of rhizodeposits and SOM decomposition) on nitrogen increase are also concerned.Furthermore

uncertainties and countermeasures and potential directions are pointed out in above three research fields.