In biogeography, soils are viewed in relation to the various factors which have created their diverse forms and potentialities. Comparisons of coniferous with deciduous woodland ecosystems consistently show the latter produce larger fluxes of nutrients from soil to foliage to soil than the former. The formation of soils depends on nested sets of environmental systems which have varying roles at different terrestrial scales. Periods of stable soil development took place during periods of complete vegetation cover while surface processes were more active when plant cover was reduced by drought or cold. Abrupt changes in the state factors determining the soil system causes sudden soil responses but it would seem that slow change over a prolonged period can similarly generate future change of a sudden nature. Within the Quaternary period soil formation has been profoundly affected by climatic change. The ecosystem of which soil is a part thus embraces not only the conservation of nature but of the whole of mankind.