This soil, typically 6 inches or so deep, was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. (treehugger.com)
But sometime within the last century, as human and livestock populations expanded, soil erosion began to exceed new soil formation over large areas. (treehugger.com)
The fact that it takes 100 years to form 1 cm of new soil under natural temperate grasslands gives an idea of the magnitude of the problem of soil loss in the EU. (sciencedaily.com)