【摘要】 土壤营养元素赋存状态和微生物活性是喀斯特地区生态恢复的关键质量指标,温室气体N2O的排放是全球变暖的重要因子。研究了雨季贵阳不同演替阶段森林表层土壤(0～10cm)微生物生物量(SMB)、反硝化酶活性(DEA)、无机氮(N)库和N转化特征,并与玉米地、茂兰喀斯特原始森林土壤做了对比分析。结果表明,微生物群落对土壤水分条件响应强烈,土壤有效N的增加有助于微生物群落的增长,土壤N转化速率越快,微生物N同化作用越低。人为干扰(火烧和农业活动)会增加或降低土壤SMB、增加潜在的气态N流失。总的来说,不同演替阶段土壤SMB、DEA和土壤N库均有显著差异,随植被恢复土壤SMB呈上升趋势,温室气体N2O的排放量呈下降趋势,气态N流失形态从N2O转变为N2,N循环过程趋于优化,表明自发演替是退化喀斯特森林恢复的可靠方式。更多还原

【Abstract】 Soil nutrients distribution and microbial activity are key qualitative index of ecology recovery in Karst regions.The emission of greenhouse gas N2O is an important factor in global warming.We have studied soil microbial biomass(SMB),denitrification enzyme activity(DEA) and nitrogen cycling characteristics on surface soil(0-10 cm) at different succession stages of forest,and compared with corn field and Maolan original forest.The results show that microbial community responses strongly to soil moisture conditions.Increasing soil available nitrogen is beneficial to the increase of microbial communities.Microbial nitrogen assimilation becomes lower when soil N converted faster.Human disturbance(fire,agricultural activities) increases or decreases the microbial biomass and increase the potential gaseous N emission.In general,microbial biomass,denitrification enzyme activity and soil N pool are significantly different during succession.Microbial biomass tends to increase but greenhouse gas N2O emission tends to reduce during the recovery of forest vegetation.The forms of gas N emission changes from N2O to N2 which optimizes the nitrogen cycle.Therefore,self-succession is a reliable method of degraded Karst forest restoration.更多还原