火干扰恢复初期土壤呼吸及其组分与土壤温湿度关系

Relationship between Soil Respiration and Its Components,Soil Temperature and Moisture Factors in the Early Stage of Fire Interference Recovery

以内蒙古大兴安岭冻土区草类-兴安落叶松林火烧迹地为研究对象,采用定位观测测定土壤呼吸、土壤温湿度变化,分析火干扰初期重度火烧迹地土壤呼吸速率(R_(S))及其组分变化,探讨土壤呼吸速率与土壤温度、湿度的相关性,寻找林火干扰恢复初期冻土区土壤呼吸及其组分规律。结果表明:林火干扰当年对土壤呼吸与土壤异氧呼吸的影响较小;随恢复时间的推移,火烧样地土壤呼吸与土壤异氧呼吸逐渐增强。火干扰后恢复的前3年,火烧样地较未火烧样地相比,R_(S)增加了13.14%,土壤异养呼吸速率(R_(H))增加了38.38%,土壤自养呼吸速率(R_(A))降低34.09%。林火干扰对土壤呼吸、土壤异养呼吸有增强作用,对土壤自养呼吸有抑制作用。林火干扰后,土壤异养呼吸的增加抵消土壤自养呼吸的减少,土壤深度为10 cm处的土壤温度(T_(10))、湿度(W_(10))均升高,R_(S)、R_(H)与T_(10)的拟合度增强,R_(A)与T_(10)的拟合度降低。林火干扰降低了土壤呼吸及其组分对T_(10)的温度敏感系数(Q_(10))。火烧样地、未火烧样地土壤呼吸及其组分与W_(10)呈显著正相关关系,但拟合系数较低(R^(2)>0.13,P<0.05)。

Taking the Grass-Larix gmelinii forest burned area in the Daxing’an Mountains of Inner Mongolia as the research object,the soil respiration rate and soil temperature and humidity changes were measured by positioning observation,and the soil respiration rate(R_(S))and its component changes in the severe burned area at the initial stage of fire disturbance were analyzed to explore the soil correlation between respiration rate and soil temperature and humidity,looking for the law of soil respiration and its composition in the frozen soil area during the initial restoration of forest fire disturbance.The disturbance of forest fire had little effect on soil respiration and soil heterotrophic respiration in the early stage of fire,with the recovery time,soil respiration and soil heterotrophic respiration in the burned area increased gradually.Compared with the unburned sampleplot,the burned areas recovered from fire disturbances increased by 13.14%,R_(S) increased by 13.14%,soil heterotrophic respiration(R_(H))increased by 38.38%,and soil autotrophic respiration(R_(A))decreased by 34.09%in the first three years.Forest fire interference enhanced soil respiration and soil heterotrophic respiration,while inhibited soil autotrophic respiration.The increase of soil heterotrophic respiration after forest fire can offset the decrease of soil autotrophic respiration.The soil temperature(T_(10))and humidity(W_(10))of the soil depth is 10 cm increased after forest fire interference.After forest fire interference,the fitting degree of R_(S) and R_(H) with T_(10) was enhanced,while that of R_(A) with T_(10) was decreased.Forest fire interference reduced the temperature sensitivity coefficient(Q_(10))of soil respiration and its components to T 10.Soil respiration and its components in the burned and unburned sample plots were significantly positive correlated with W_(10),but the fitting coefficient was low(R^(2)>0.13;P<0.05).