Environmental controls and the influence of vegetation type, fine roots and rhizomorphs on diel and seasonal variation in soil respiration
Environmental controls and the influence of vegetation type, fine roots and rhizomorphs on diel and seasonal variation in soil respiration
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DOI：
10.1111/j.1469-8137.2008.02481.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Allen, Michael F.
中科院分区：
文献类型：
--
作者：
Vargas, Rodrigo;Allen, Michael F.
土壤呼吸的时空变化特征与细根和根形态的动态耦合是理解土壤呼吸调节机制的必要条件。采用密集无线网络阵列土壤CO2传感器与微型电子管相结合的方法，在美国加利福尼亚州混合针叶林中连续测量了1年以上的土壤呼吸，在两个相邻的不同植被类型的区域：木本植被区（W-v）和分散的草本植被区（H-v）。土壤年呼吸速率、细根和根茎长度在W-v条件下大于H-v条件下。土壤呼吸与W-v条件下的细根和根状形态呈正相关，与H-v条件下的细根呈正相关。土壤呼吸模式和季节呼吸模式在W-v下与土壤温度不耦合，而在H-v下则不耦合。当解耦时，在温度升高时观察到较高的土壤呼吸速率，显示出滞后效应。土壤呼吸的温度依赖分量和光合有效辐射的变化分量可以解释W-v时的土壤滞回。结果表明，除光、温、湿变化外，植被类型、细根和根形态动态也影响土壤呼吸。
Characterization of spatial and temporal variation of soil respiration coupled with fine root and rhizomorph dynamics is necessary to understand the mechanisms that regulate soil respiration.A dense wireless network array of soil CO2 sensors in combination with minirhizotron tubes was used to continuously measure soil respiration over 1 yr in a mixed conifer forest in California, USA, in two adjacent areas with different vegetation types: an area with woody vegetation (W-v) and an area with scattered herbaceous vegetation (H-v).Annual soil respiration rates and the lengths of fine roots and rhizomorphs were greater at W-v than at H-v. Soil respiration was positively correlated with fine roots and rhizomorphs at W-v but only with fine roots at H-v. Diel and seasonal soil respiration patterns were decoupled with soil temperature at W-v but not at H-v. When decoupled, higher soil respiration rates were observed at increasing temperatures, demonstrating a hysteresis effect. The diel hysteresis at W-v was explained by including the temperature-dependent component of soil respiration and the variation dependent on photosynthetically active radiation.The results show that vegetation type and fine root and rhizomorph dynamics influence soil respiration in addition to changes in light, temperature and moisture.