In eastern Australia, two Catchment Management Authorities have begun programs to encourage farmers and graziers to manage for increased soil organic matter. Both programs involve measuring on-farm results with before and after soil testing. Both programs are aimed at enhancing soil health and the sustainability of farming, rather than at "offsets" to fossil fuel emissions.
Soil scientist Ray Archuleta shows a remarkable contrast in the responses of tilled and no-tilled soil to water. Note that the biological glue he speaks of during the second half, substances such as glomalin, are one of the important large compounds that contain soil carbon. The takeaway from this demonstration is also that soil organic carbon has huge leverage on the effectiveness of the water cycle. See also http://managingwholes.com/eco-water-cycle.htm
Charles E. Kellogg wrote an essay published in the United States Department of Agriculture's 1938 Yearbook of Agriculture (Soils and Men). Thanks to Abe Collins for the tip.
John Todd, of Living Machines fame and the New Alchemy Institute, has an interesting essay on http://www.thesolutionsjournal.com/node/634 about the need for our urban and industrial society to understand the foundational role of soil, and the carbon cycle.