Soil-the thin outer skin of the Earth's land-is a critical and fragile natural resource. Soil is the basis for almost all global agriculture and the medium in which most terrestrial biological activity occurs. Here, we reconsider the five forming factors of soil originally suggested more than a century ago (parent material, time, climate, topography, and organisms) and updated over the years to add human activity as the sixth forming factor. We demonstrate how present anthropogenic activity has become the leading component influencing each one of the original forming factors. We thus propose that, starting from the Anthropocene, human activity should no longer be considered as a separate forming factor but rather a main driving force of each of the five original ones. We suggest that the importance of soil and the strong direct and indirect effects of anthropogenic factors on soil-forming factors should be considered together to ensure sustainability of this critical resource.
© 2021 The Authors. Published by American Chemical Society.