林火是影响多年冻土稳定性的主要因素之一,对火后多年冻土区土壤微生物生物量碳氮的变化特征进行分析,为火后冻土土壤恢复提供理论依据.以大兴安岭漠河2002年火烧灌丛湿地为研究对象,在未火烧和火烧区分别随机设置5个试验样地采用土钻分别采集土壤深度(h)为0＜h≤30 cm和30 cm＜h≤60 cm 土层土壤土样,分析火后0～60 cm 土层土壤理化性质和土壤微生物生物量碳/氮(MBC/MBN)的变化特征.结果表明:(1)火烧样地0＜h≤30 cm和30 cm＜h≤60 cm 土层的MBC质量分数分别降低54.69％和53.11％,MBN质量分数分别降低38.77％、33.00％.(2)火烧样地0＜h≤30 cm 土层的土壤温度和土壤密度分别增加90.82％、161.54％,土壤含水率、全碳质量分数和全氮质量分数分别降低88.51％、48.57％和32.98％;30 cm＜h≤60 cm 土层的土壤温度、土壤含水率、硝态氮(NO3--N)质量分数和pH分别增加213.26％、24.23％、38.36％和3.75％,土壤全碳、全氮和全磷质量分数分别降低44.70％、38.0％和31.03％.(3)在0＜h≤30 cm 土层,MBC、MBN与土壤含水率、土壤全碳、全氮和全磷质量分数呈显著正相关关系,与土壤密度和林火强度(FS)呈显著负相关关系,土壤全碳质量分数、土壤密度和林火强度是影响MBC和MBN的主要因子;在30 cm＜h≤60 cm 土层,MBC、MBN与全碳质量分数、全磷质量分数呈显著正相关关系,与土壤密度呈显著负相关关系;土壤密度、全碳质量分数和土壤含水率是影响MBC和MBN的主要因子.
Effects of Forest Fires on Soil Microbial Biomass Carbon and Nitrogen in Shrub Wetlands of the Permafrost Zone in the Greater Khingan Range
Forest fires are one of the main factors affecting the stability of permafrost.This study analyzes the changes in soil mi-crobial biomass carbon and nitrogen in permafrost zones after fire,providing a theoretical basis for soil recovery post-fire.The research was conducted in the shrub wetlands of Mo'he,Greater Khingan Range,which experienced a forest fire in 2002.Five experimental plots were randomly established in both unburned and burned areas,where soil samples were col-lected at depths of 0＜h≤30 cm and 30 cm＜h≤60 cm using a soil auger.The study analyzed the physicochemical properties of the soil and the changes in microbial biomass carbon(MBC)and nitrogen(MBN)in the 0-60 cm soil layer after fire.The results showed that:(1)The mass fraction of MBC in the burned site decreased by 54.69％and 53.11％for the 0＜h≤30 cm and 30 cm＜h≤60 cm layers,respectively,while the mass fraction of MBN decreased by 38.77％and 33.00％,respectively.(2)In the burned site,the soil temperature and soil density of the 0＜h≤30 cm layer increased by 90.82％and 161.54％,respectively,and the soil moisture content,total carbon mass fraction,and total nitrogen mass fraction sig-nificantly decreased by 88.51％,48.57％,and 32.98％,respectively.For the 30 cm＜h≤60 cm layer,the soil tempera-ture,soil moisture content,nitrate nitrogen(NO3-N)mass fraction,and pH increased by 213.26％,24.23％,38.36％,and 3.75％,respectively,while the mass fractions of total carbon,total nitrogen,and total phosphorus decreased by 44.70％,38.0％,and 31.03％.(3)In the 0＜h≤30 cm layer,MBC and MBN showed a significant positive correlation with soil moisture content,total carbon,total nitrogen,and total phosphorus mass fractions,while exhibiting a significant negative correlation with soil density and fire severity(FS).The total carbon mass fraction,soil density,and fire severity were the primary factors influencing MBC and MBN.In the 30cm＜h≤60cm layer,MBC and MBN were significantly posi-tively correlated with total carbon and total phosphorus mass fractions and significantly negatively correlated with soil densi-ty.Soil density,total carbon mass fraction,and soil moisture content were the main factors affecting MBC and MBN.
万方数据
维普
