Soil Formation

Soils form a unique and irreplaceable essential resource for all terrestrial organisms, including man. Soils form not only the very thin outer skin of the earth's crust that is exploited by plant roots for anchorage and supply of water and nutrients. Soils are complex natural bodies formed under the influence of plants, microorganisms and soil animals, water and air from their parent material, i.e. solid rock or unconsolidated sediments. Physically, chemically and mineralogically they usually differ strongly from the parent material, and normally are far more suitable as a rooting medium for plants. In addition to serving as a substrate for plant growth, including crops and pasture, soils play a dominant role in the biogeochemical cycling of water, carbon, nitrogen and other elements, influencing the chemical composition and turnover rates of substances in the atmosphere and the hydrosphere. Soils take decades to millennia to form. We tread on them and do not usually see their interior, so we tend to take them for granted. But improper and abusive agricultural management, careless land- clearing and reclamation, man-induced erosion, salinisation and acidification, desertification, air- and water pollution, and withdrawal of land for housing, industry and transportation now destroy soils more rapidly than they can be formed.

Klappentext

This is an essentially new text, dealing with qualitative and quantitative aspects of soil formation, underlying chemical, biological, and physical processes, and their measurable results. The starting point of the text is not soil classification, but weathering of parent materials, mobilization, transport, and immobilization of dissolved and suspended compounds, placed in the context of biosphere and geosphere. Connections between processes and diagnostic horizons of soil classification are discussed. Emphasis is laid on the universality of soil-forming processes and on the soil as a dynamic entity that forms part of the total environment. The complex genesis of many soils gets its deserved attention. The text is full of examples from literature and the student is guided through the book by a large number of questions and problems, the answers to which are also given.

Inhalt
Why Soil Genesis?.- Basic Processes.- Soil Physical Processes.- Soil Chemical Processes.- Biological Processes in Soils.- Soil Profile Development.- Studying Soil Profiles.- Organic Surface Horizons.- Hydromorphic Soils.- Textural Differentiation.- Formation of Calcic, Gypsiferous, and Saline Soils.- Formation of Vertisols.- Podzolization.- Formation of Andisols.- Ferralitization.- Dense and Cemented Horizons: Fragipan and Duripan.- Analysing Complex Situations.