Measuring soil organic carbon stocks - issues and considerations

摘要

Increasing soil organic carbon (SOC) stocks has been widely discussed as a short- to mid-term implementable solution to the problem of rising atmospheric greenhouse gas (GHG) concentrations, with the technical mitigation potential of soil carbon sequestration around 5 GtCO_2eq/yr by 2030. However, as the spatial variability of SOC is high, coefficients of variation in SOC stocks can rise sevenfold when scaling up from point sample to landscape scales, resulting in high uncertainties in calculations of SOC stocks. This hinders the ability to accurately measure changes in stocks at scales relevant to emissions trading schemes (ETSs). Further, the depth distribution of SOC has not been thoroughly investigated, resulting in possible underestimations ofcarbon sequestration due to inadequate sampling depth. Research is needed to eliminate these uncertainties in SOC stocks and enable soil organic carbon to be incorporated into ETSs. Reliable and low-cost methodologies for measuring SOC are also required,so analysis costs do not outweigh carbon credits. When assessing SOC stocks, sampling and analysis must be carefully planned to avoid bias and ensure accurate calculations.