Search results
Results from the WOW.Com Content Network
Vertisols of the world A more detailed map of the global distribution of Vertisols. A vertisol is a Soil Order in the USDA soil taxonomy [1] and a Reference Soil Group in the World Reference Base for Soil Resources (WRB). [2] It is also defined in many other soil classification systems. In the Australian Soil Classification it is called ...
Expansive clay, also called expansive soil, is a clay soil prone to large volume changes (swelling and shrinking) directly related to changes in water content. [1] Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols.
Gregory John Retallack (born 8 November 1951) is an Australian paleontologist, geologist, and author who specializes in the study of fossil soils (paleopedology).His research has examined the fossil record of soils though major events in Earth history, extending back some 4.6 billion years. [1]
Due to the physical and chemical properties of some clays [4] (such as the Lias Group) large swelling occurs when water is absorbed. Conversely when the water dries up these clays contract (shrink). The presence of these clay minerals is what allows soils to have the capacity to shrink and swell.
Age and origin of the source material determine the chemical structure of humic substances. In general, humic substances derived from soil and peat (which takes hundreds to thousands of years to form) have higher molecular weight, higher amounts of O and N, more carbohydrate units, and fewer polyaromatic units than humic substances derived from ...
Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles. [2] Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of ...
Unweatherable parent materials – sand, iron oxide, aluminium oxide, kaolinite clay. Erosion – common on shoulder slopes; other kinds also important.; Deposition – continuous, repeated deposition of new parent materials by flood as diluvium, aeolian processes which means by wind, slope processes as colluvium, mudflows, other means.
Most research on anthropogenic soils describes specific aspects of their biology, chemistry or physical properties, cultural heritage and human geography, erosion, wastes, pollution, fertilizer management, and taxonomy. Very few of them, [3] [4] [5] try to answer to the question: How fast do they start pedogenesis (viz., differentiating horizons)?