Usefulness of the carbon-13 tracer technique for characterizing terrestrial carbon pools

Application of the carbon-13 (¹³C) tracer technique to soil organic carbon emission is relatively new to many researchers and only a few results have been reported to date. This mini-review paper cites some well-documented research in organic carbon pool studies using the ¹³C tracer technique. The ¹³C abundance in soil usually remains at a stable level under a set of natural conditions. Variations in ¹³C reflect different sources and types of organic components from natural environments. An important feature of ¹³C discrimination in the soil C pool has permitted researchers to assess the dynamic nature of the pool. This discrimination may reflect a selective preference at early stage of residue decomposition by soil microbes. Crop rotation and residue input to humic substances can change the ¹³C abundance, which is a possible way to estimate soil C emission. However, the dynamic relationship between ¹³C abundance in the soil C pool and C emission is still in an early stage of development. Restrictions due to requirement of long-term experiments and duration of vegetation changes may affect its wide-spread adoptions in C emission studies. This revised version was published online in August 2006 with corrections to the Cover Date.