Measuring and Monitoring Soil Carbon Storage.

The exchange of carbon between land and the atmosphere is crucial to ecosystem function and performance.  Of the main biologically-mediated greenhouse gases, carbon dioxide is unique in that time-integrated fluxes may be estimated from high-resolution measurements of temporal changes in soil carbon storage.  That is, fluxes over a period of years may be inferred from temporal changes in soil carbon stocks.  We will review the sampling and analytical variables that may have the greatest influence on the accuracy and precision of soil carbon and nitrogen estimates, and suggest strategies to estimate soil carbon in field studies of carbon and nitrogen cycling.