Agriculture Reference
In-Depth Information
America and Asia. The hydrolytic environments cover the largest areas of the terrestrial
surface and the major processes dominating in these areas are, in decreasing order of
importance, hydrolysis, acido-complexolysis, salinolysis and alkalinolysis. The areas of
arid climate have lower rates of chemical weathering and are dominated by salinolysis
and alkalinolysis; little chemical weathering occurs in the extreme desert environments.
3.2
Formation and structure of organic reserves
3.2.1
DYNAMICS OF ACCUMULATION
Living organisms colonise soils from the very early stages of their formation.
Photolithotrophic micro-organisms and plants fix atmospheric carbon and nutrients from
the weathering parent materials and incorporate them into their tissues.
While they live, plants release such metabolites as root exudates and foliar and bark
leachates into the soil. These are supplemented with microbial by-products and animal
mucus and polysaccharides to form part of the metabolic organic matter defined
by Parton
et al.
(1983) (Figure II.4).
