Abstract:Soil microclimate and chemical/physical properties are among the key regulatory variables determining microbial activities in forest soils. We manipulated moss cover (i.e., modifications of soil microclimate) and added nitrogen in an interior forest and an area of edge influence (AEI) to examine how changes in microclimate and N addition may alter the soil microbes. With N addition, we found decreased pH and elevated N and P, although moss removals and ecotope complicated the changes of soil properties and their responses to N treatment. Overall, moss cover alleviated the stress of soil acidification, decreased available N, and stimulated the available P at N addition conditions. The above changes produced significant influences on soil microbial communities. The low N addition lowered the environmental stress of soil microorganisms at the AEI, while the intermediate and high level of N additions increased environmental stresses. Any N addition increased the environmental stress of soil microorganisms at the interior forest. The moss cover treatment decreased the environmental stresses on soil microorganisms and, consequently, enhanced the soil microbial metabolic activities.