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首页> 外文期刊>Agricultural and Forest Meteorology >Estimating heterotrophic and autotrophic soil respiration using small-area trenched plot technique: theory and practice.
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Estimating heterotrophic and autotrophic soil respiration using small-area trenched plot technique: theory and practice.

机译：使用小面积地沟图技术估算异养和自养土壤的呼吸作用：理论和实践。

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摘要

The trenching method of root exclusion is generally used to estimate heterotrophic (microbial decomposition) (Fh) and autotrophic (root and associated rhizosphere respiration) (Fa) components of soil respiration (F0), particularly in forest ecosystems. However, some uncertainties exist on the accuracy and interpretation of the results from such experiments using small-area root exclusion plots. Using field and laboratory measurements as well as simulations using a process-based model of CO2 production and transport in soil, we show that: (a) CO2 concentrations at or immediately below the depth of root exclusion in small-area root exclusion plots are similar to those at the same depth in nearby undisturbed soil and (b) the contribution of soil CO2 flux from below the root exclusion depth to the measured efflux at the surface of a root exclusion plot (F0re) is increased because of the higher concentration gradient at the bottom of the root exclusion layer due to the decreased rate of CO2 production above this depth. Consequently, Fa, calculated as F0c measured in control (non-disturbed) plots minus F0re measured in root exclusion plots, is underestimated. We describe an analytical model, derived from the soil CO2 production and diffusion equation, to obtain correct estimates of Fa measured using small-area root exclusion plots. The analytical model requires knowledge of depth distribution of soil CO2 diffusivity and source strength as inputs..
机译：根系排除的挖沟方法通常用于估计土壤呼吸作用（F0）的异养（微生物分解）（Fh）和自养（根和相关的根际呼吸）（Fa）成分，尤其是在森林生态系统中。但是，在使用小面积根系排除图进行此类实验的结果的准确性和解释上存在一些不确定性。使用田间和实验室测量以及使用基于过程的土壤中CO2产生和运输的过程模型进行的模拟，我们表明：（a）在小面积根系排斥图中，根系排斥深度处或紧邻其下方的CO2浓度相似（b）从根排斥深度以下的土壤CO2通量对根排斥图（F0re）表面测得的流出量的贡献增加了，因为由于在该深度以上CO2的生成速率降低，根部排斥层的底部。因此，Fa被低估了，Fa计算为在对照（非扰动）图中测得的F0c减去在根排除图中测得的F0re。我们描述了一种从土壤CO2产生和扩散方程式得出的分析模型，以获得使用小面积根系排斥图测得的Fa的正确估计。该分析模型需要了解土壤CO2扩散深度分布和源强度作为输入。

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