can anybody give e me range of values for the ratio between Water-Extractable Organic Carbon and the Total Carbon (determined with combustion) of a (clay) soil?
Also references to the literature would be greatly appreciated.
I had a student several years ago that evaluated this question under monoculture grass species. His findings were that at the time of sample collection, (this was one point in time) that the water-soluble C consisted 3-7% of the total organic C. This probably varies seasonally and with seasonal climate changes but it appears that there is a consistent presence of WSOC that can contribute to deep soil C movement and accumulation.