... unlike the plant, they usually possess much more of the latter than of the former In the plant, the organic matter constitutes the most considerable portion of the whole In the soil, on the contrary, ... of the entire soil, sometimes less and it has no reference to the sand, clay, and vegetable matters which they contain From analyses of many fertile soils, and of others which are barren or of ... soils What is the general rule concerning the composition of rocks? Do these distinctions affect the fertility of soils formed from them? What we mean by the mechanical character of the soil? Is its...