“Be it deep or shallow, red or black, sand or clay, the soil is the link between the rock core of the earth and the living things on its surface. It is the foothold for the plants we grow. Therein lays the main reason for our interest in soils.” --- Roy W. Simonson, USDA Yearbook of Agriculture, 1957. The British naturalist Charles Darwin (1809–1882) was probably the first scientist to examine a soil profile and suggest factors responsible for the structure of the various layers. Nowadays, Soil Science is the science dealing with soils as a natural resource on the surface of the Earth, including soil formation,.