How long does it take for soil to form?

The answer

Very long by human standards: soil forms through the weathering of rock and the slow addition of organic material. FAO notes that soil formation and regeneration processes are predominantly slow, so soil lost to erosion or burial should be treated as irreplaceable within a lifetime. The UN Convention to Combat Desertification says current farming practices erode soils up to 100 times faster than natural processes replenish them. Fertility and structure, however, can be improved much faster than a whole soil can form.