Re: Mollic epipedon carbon

There is no such requirement for the carbon in the mollic (or umbric) epipedon. It could be included as a criterion, but then we would have to consider how to actually determine this. Doing that would likely be problematic because a surface horizon may have very old carbon (as in human transported material), but it will also have newer carbon from recent vegetation. There may be a way to make a meaningful separation based on the form of the organic matter itself rather than its age that might be more feasible to determine in the lab. This may be something worth pursuing as a way to exclude this particular anthropogenic influence in some soils. Determining age directly may be too difficult and costly to be practical.