Abstract: Soil microorganisms play important roles in material and energy flows of terrestrial ecosystems; understanding the changes of function and structure of soil microorganisms is of great significance to the study of the whole ecosystem. In order to evaluate the effect of the mixed Pinus tabuliformis Carr. + Quercus mongolica Fisch. ex Ledeb. forest on soil microbial community functional diversity, by using Biolog Ecoplate system, this paper studied the functional diversity of soil microbial community under three different vegetation types in Jianping County, Liaoning Province, including pure P. tabuliformis Carr. forest (YC), novegetation soil (NP), and mixed P. tabuliformis Carr. + Q. mongolica Fisch. ex Ledeb. forest (YM). The results showed that soil microbial metabolic activity (AWCD) was in the order of YM>YC>NP, and soil microbial metabolic activity of NP was the lowest. There were variations in carbon utilization by soil microbial communities among the three plantation forests. Soil microbes in the mixed forest had significantly higher utilization rates in L-asparagine, L-phenylalanine, L₄₀ serine, L-threonine, Tween-40, D-galactose acid-γ-fat, phenethylamine, D-glucose, amino acid, 4-hydroxy benzoic acid than in the YC (P<0.05). Principal component analysis showed that carbohydrate and amino acids were important factors affecting soil metabolic activity. The Shannon’s diversity index of soil microbes was not significantly different among the three plantation forests. The McIntosh’s index was in order of YM>YC>NP, while there was no significant difference in Simpson’s index between the YM and YC, and both had significantly higher Simpson’s index than NP. Our results demonstrated that planting P. tabuliformis and Q. mongolica trees together can promote soil microbial activity.

Key words: MTCLIM model, net primary productivity, topographic factor., 3PGS model, fire severity