How fast does soil grow?

Quantifying the rate of soil formation has become important in response to the consideration of soil as a renewable resource. The availability of new sophisticated laboratory techniques has opened up the possibility of addressing the demand of quantifying processes of soil landscape evolution in the critical zone. Here, we investigated the rate of soil formation of world soils based on published results of TCN-derived (terrestrial cosmogenic nuclides, Be-10) soil production rates (SPR). The compilation of published TCN-derived SPR for different climatic zones and lithologic conditions showed exponentially decreasing SPR with increasing soil thickness for the majority of the discussed studies. This implies that the presence of a soil mantle protects the bedrock from further weathering. We found that rates of soil production in Australia appear to be similar in range when compared with other parts of the world. We concluded that we can formulate an average quantitative estimate of 'global' soil production based on TCN: soil production rate (mm kyr(-1)) = 114 +/- 11 exp (-2.05 soil thickness in mm). Such a rate is useful for global modelling of soil formation to better understand the role of soils in landscape evolution. (C) 2013 Elsevier B.V. All rights reserved.