| 亚热带次生林不同土壤呼吸组分的多年观测研究 |
| 摘要点击 1549 全文点击 1098 投稿时间：2014-07-06 修订日期：2014-09-18 |
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| 中文关键词 次生林 土壤呼吸 异养呼吸 自养呼吸 温度敏感系数 |
| 英文关键词 secondary forest soil respiration heterotrophic respiration autotrophic respiration temperature sensitivity coefficient |
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| 中文摘要 |
| 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. |
| 英文摘要 |
| A four-year field experiment was performed from March 2010 to February 2014 in order to investigate the contribution of different respiratory components to soil respiration and the temperature sensitivity of different respiratory components. Four blocks were arranged in field, and there were trenched and un-trenched plots in each block. Trenching, which can exclude roots, was performed around the trenched plots. A portable soil CO2 fluxes system (Li-8100) was used to measure soil respiration rates. Soil temperature and soil moisture were simultaneously observed when measuring soil respiration rates. The results showed that the heterotrophic respiration rate in the trenched plots and the soil respiration rate in the un-trenched plots had the same seasonal pattern. Soil respiration rate in the un-trenched plots was significantly (P<0.001) higher than that in the trenched plots. Mean soil respiration rates in un-trenched plots and mean heterotrophic respiration rate in trenched plots were (2.59±0.48) and (1.74±0.28) μmol·(m2·s)-1, respectively. There was no significant (P>0.05) difference in the mean soil respiration rate or mean heterotrophic respiration rate between measurement years. The relationship between heterotrophic respiration and soil respiration could be fitted with a proportion function. Heterotrophic and autotrophic respiration contributed 65.9% and 34.1% to the soil respiration, respectively. The main contributor to soil respiration was heterotrophic respiration. The relationship between the ratio of heterotrophic respiration to soil respiration and measurement date could be fitted with a linear function. An exponential function could be used to fit the relationship between heterotrophic respiration and soil temperature, and between autotrophic respiration and soil temperature. The temperature sensitivity coefficient (Q10) for heterotrophic respiration was lower than that for autotrophic respiration. |
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