University of California – Davis in Science Daily – August 14, 2019
In addition to this article, the following clarifications by Dr Beverley Henry, member of the “4 per 1000” STC: “When both compost and cover crops were added in the organic-certified system, soil carbon content increased 12.6 percent over the length of the study, or about 0.07 percent annually.
That’s more than the international “4 per 1000” initiative, which calls for an increase of 0.04 percent of soil carbon per year. It is also far more carbon stored than would be calculated if only the surface layer was measured.”