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为研究亚热带次生林不同土壤呼吸组分对土壤呼吸的贡献率及土壤呼吸组分的温度敏感性,于2010-03-2014-02进行了4 a的野外观测试验.设置了4个随机区组,每个区组设置断根和不断根处理,在断根小区四周挖壕沟以防止根系进入断根小区.采用Li-8100便携式土壤碳通量测定系统观测不同处理的土壤呼吸,并同步观测土壤温度和土壤湿度.结果表明,不断根小区的土壤呼吸速率和断根小区的异养呼吸速率均具有明显的季节变异规律,不断根小区的土壤呼吸速率量值极显著(P<0.001)高于断根小区的异养呼吸速率量值.4 a观测期间不断根处理平均土壤呼吸速率为(2.59±0.48)μmol·(m2·s)-1,而断根处理平均土壤呼吸速率为(1.74±0.28)μmol·(m2·s)-1.不同年份观测的土壤呼吸速率的年平均值之间无显著差异(P>0.05),各年份异养呼吸速率的年平均值之间亦无显著差异(P>0.05).土壤呼吸中的异养组分与土壤呼吸之间的关系可用比例函数方程拟合,异养呼吸占土壤呼吸的比例为65.9%,自养呼吸占土壤呼吸的比例为34.1%,异养呼吸是土壤呼吸的主要组成部分.随着观测时间的延长,异养呼吸占土壤呼吸的比例呈线性下降趋势.异养呼吸速率和自养呼吸速率与土壤温度之间的关系均可用指数方程拟合,异养呼吸的温度敏感系数Q10值低于自养呼吸的Q10值.
In order to study the contribution of different soil respiration components to soil respiration and the temperature sensitivity of soil respiration components in subtropical secondary forests, a 4-day field experiment was conducted from March 2010 to February 2014. Four randomized field groups were set up, Each group set up root-cutting and root-processing, digging trenches around the root-cutting plot to prevent the root system from entering the root-breaking community.Use Li-8100 portable soil carbon flux measurement system to observe the different treatment of soil respiration, and simultaneously observe the soil temperature and soil moisture The results showed that both the soil respiration rate of the continuous root zone and the heterotrophic respiration rate of the severed root zone all had obvious seasonal variations. The soil respiration rate of the continuous root zone was significantly (P <0.001) higher than that of the root zone The average soil respiration rate was (2.59 ± 0.48) μmol · (m 2 · s) -1 for continuous rooting during the observation period while the average soil respiration rate after root cutting was (1.74 ± 0.28) μmol · (m 2 · s) s) -1. There was no significant difference (P> 0.05) between the annual average of soil respiration rate observed in different years, and no significant difference (P> 0.05) between the annual average of heterotrophic respiration rate in each year. Heterotrophic group in the breath The relationship between soil respiration and soil respiration can be fitted by the proportional function equation. The proportion of heterotrophic respiration to soil respiration is 65.9%, that of autotrophic respiration to soil respiration is 34.1%, and heterotrophic respiration is the main component of soil respiration. With the extension of observation time, the proportion of heterotrophic respiration to soil respiration decreased linearly.The relationship between heterotrophic respiration rate and autotrophic respiration rate and soil temperature can be fitted by exponential equation, the temperature sensitivity coefficient of heterotrophic respiration The Q10 value is lower than the Q10 value of autotrophic respiration.