Objective  The response of amino sugar transformation characteristics of temperate forest soil to exogenous nitrogen (N) and litter addition is of great significance for temperate forest soil N management and alleviating the negative effects of N deposition.

  Method  A laboratory incubation of organic layer (O-layer) of temperate forest soil samples was conducted to study the dynamics of three kinds of microbial-derived amino sugars after adding N and litter. The relative contribution of soil fungal and bacterial residues to soil N transformation and accumulation was also investigated by the ratio of glucosamine to muramic acid.

  Result  The results showed that the responses of amino sugars from different microbial sources to the addition of exogenous substances were different in the O-layer of temperate forest soil. The N addition only treatment (N) and the combination of N and litter addition treatment (N + L) both were beneficial to the accumulation of bacterial residues, while the N treatment had no effect on the accumulation of fungal residues, and the N + L treatment was detrimental to the accumulation of glucosamine. The response of galactosamine to extraneous substances addition was weak. Since the stability of fungal residues was higher than that of bacterial residues, the N + L treatment could be detrimental to the stability of soil microbial residues. The ratio of a fungi-derived amino sugar to bacteria-derived amino sugar in soil was affected by the addition of exogenous substances. The ratio decreased in the N and N + L treatments (decreased by 28.32% and 30.50%, respectively), which indicated that the contribution of bacterial residues to soil N transformation was greater that of fungal residues after the addition of exogenous substances.

  Conclusion  The addition of exogenous N and litter changes the transformation process of microbial residues in the O-layer of temperate forest soil.