The long, long travel from rock to soil (I)

There is hardly a subject in all nature, of which the majority of people has so unclear terms and which has hitherto been so completely misunderstood, as the soil on which they walk.

F.A. Fallou

Soil is often considered as the skin of the Earth and is located at the interface between the lithosphere, hydrosphere, atmosphere and biosphere. Air, water, rock and living beings interact to form soil, which, in turn, is the physical and nutritional support for living organisms in emerged areas. Currently, we define soil is an open system that temporarily stores the necessary resources for living organisms. The availability of these resources (water, energy, mineral nutrients, etc.) depends on the intensity and speed of exchange processes between soil and the rest of compartments of ecological systems.

Soil in the interface, by Antonio Jordán. Distributed by Imaggeo.

But the concept of soil has been modified in accordance to the increasing understanding of its components and the relations among them. During centuries, soil was considered not more than dirt on rocks, when not simply one of the strata in geological profiles. See, for example, the following statement: “That all the earthy part of soil consists of minute fragments of rock does not require argument, or need proof, but inspection merely to determine it. We have only to place specimens under the magnifier and their rocky origin will become manifest” (Eaton and Beck, 1820). Continue reading