Soil Carbon Dynamics: Separating autotrophic and heterotrophic components of soil respiration: lessons learned from trenching and related root-exclusion experiments

摘要: INTRODUCTION Soil respiration ( R S , Fig. 8.1) is the sum of an autotrophic component A ) produced by roots and associated rhizosphere (mycorrhizae bacteria) a heterotrophic H originating from soil micro-organisms that decompose organic materials both above-ground below-ground litter (Bowden et al ., 1993; Boone 1998; Epron 1999). Autotrophic involves root carbohydrates exudates have very low residence time in soil, while carbon compounds with longer time, ranging months to years for fresh centuries old matter. All components are thought be differently influenced climatic conditions site characteristics (Boone 2001; Lavigne 2004; Dilustro 2005) respond elevated atmospheric CO 2 or warming (Rustad King Pendall Soe Eliasson 2005). Thus, separate estimations these required analyzing modelling its response climate perturbation, providing better knowledge budgets ecosystems improving sequestration (Hanson 2000; Ryan Law, 2005; Subke 2006).