How crops feed. A treatise on the atmosphere and the soil as related to the nutrition of agricultural plants

The colluvium and alluvium problem: Historical review and current state of definitions

“…Thus, colluvium started to become a unique category of sediments. Johnson (1880) proposed in the classification of transported soil, mainly represented by drift (diluvium) and alluvial, a third class called colluvium to designate diluvium and alluvium like sediment containing angular rock fragments or when distinction between diluvium and alluvium is impossible:…”

“…"Colluvial Soils, lastly, are those which, while consisting in part of drift or alluvium, also contain sharp, angular fragments of the rock from which they mainly originated, thus demonstrating that they have not been transported to any great distance, or made up of soils in place, more or less mingled with drift or alluvium" (Johnson, 1880) The addition of angular rock fragments as a criterion for colluvium began the shift away from fluvial processes.…”

“…John Wesley Powell (1888), who was the director of the United States Geological Survey at the time, proposed the name "overplacement soils" to describe soil formed in material "transported by gravity", such as talus, landslides, and alluvial cones. Although hinted at in characteristics listed in the colluvium definitions provided by Kerr (1875) and Johnson (1880), this concept of mass-gravity being the defining mode of transport constituted a fundamental change in the classification of transported materials and had a crucial effect on the colluvium definition in the USA. In the same year, the Russian, Aleksey Petrovich Pavlov (1888) introduced the word "deluvium" instead of "colluvium" to designate accumulation of sediment along or at the footslopes of hills after rainfall (Teisseyre, 1991;Baužienė et al, 2008;Kittel, 2014).…”

“…In this movement it is impelled by gravity abetted by frost action, the expansion of roots, the overturning movement of uprooted trees, and the burrowing work of a host of animals. " Shaler (1892) In line with this concept, but heralding back to the logic provided by Kerr (1875) and Johnson (1880), Cook (1897) evoked the term colluvial as he wrote, "When colluvial soils contain angular fragments of the rocks from which they have in part originated, it may be inferred that such soils were not transported from any very great distance. "…”