| A field experiment was conducted in a natural mixed Pinus tabulaeformis Car. and Quercus Haotungensis Koidz. forest stand in the Lingkong Mountain nature reserve, Shanxi Province, to study the effects of different quantity and quality of litter and different nitrogen addition rates on0～10cm soil microbial biomass carbon and nitrogen (MBC and MBN), microbial activity (MR) and soil quantity using randomized complete block design, and sixty2m×2m plots were installed. The litter treatments include complete litter removal (N), doubling of leaf litter (L), doubling of woody litter (B) and doubling of mixed leaf and woody litter (LB), and the nitrogen addition rates are:0,5g·m-2·a-1, and10g·m-2·a-1.After data analysis, we got that:1) MBC, MBN and MR varied in the ranges of262.42～873.16mg·kg-1,73.55～173.85mg·kg-1and2.38～3.68mg·kg-1·d-1, respectively, with significant and positive correlations among each other. Nitrogen addition did not show any effect on MBC、MBN and MR, whereas litter treatment significantly affected MR, which was the highest under LB treatment, higher under L treatment and the lowest under N treatment. And there were no interactive effects between litter and nitrogen addition treatments on any of the variables studied;2) While doubling of forest floor litter decreased soil bulk density significantly, soil organic carbon (SOC) was significantly increased, which was higher under LB and L treatments than that under B and N treatments. Especially, SOC increased the highest was under LB treatment when nitrogen addition rate at5g·m-2·a-1, while soil bulk density was decreased the highest. Except soil total nitrogen decreased significantly under N treatment when nitrogen addition rate at0, there was no significant difference among the effects of other litter and nitrogen addition on soil bulk density, and soil pH was not affected significantly by different quantity and quality of litter and different nitrogen addition rate. |
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