World Congress of Soil Science Logo 18th World Congress of Soil Science
July 9-15, 2006 - Philadelphia, Pennsylvania, USA
International Union of Soil Sciences

Tuesday, 11 July 2006
44-3

This presentation is part of 44: 2.4A Poorly Ordered Nanoparticulate materials (PONM) in Soils - Theater

Global Laws of Genesis and Geography Nanoscopic the near Order Minerals in Soilforming Rocks and Soil.

Boris Gradusov, Soilsince Institut of V.V. Dokuchaev, Pyshevsky, 7, Moscow, Russia

468334 1. The representation about a low degree of ordering of structure of clay minerals of soil for a long time exists in soil science and mineralogy of clays . The properties and genesis of minerals of a clay type with near order are considered by the author earlier. Among many attributes of minerals of the near order main is till now x-ray. In work on the laws of genesis and geography of these minerals are considered on the basis of a complex of methods: macroscopic (granulometric, microaggregate and total chemical), and also micro-nanoscopic - x-ray. Characteristic for the very low intensity x-ray bazal reflections even at removal of organic substances and oxides of iron is caused by defects of structure, its mixed-layer distribution by the disorder type, and also imperfection of imposing of layers on bazal plane owing to aggregation of particles. 2. Nanoscopic poorly-ordered clay minerals (PONmin) in soils are submitted: smectite, mixed-layer mica - smectite and chlorite-smectite, including di- and di - triokhtahedral, halloysite, allophane. They are accompanied by the poorly disorder forms hydrooxids-oxides of aluminium and iron. 3. The basic source PONmin are soilforming rocks. The minerals are dated for three types of rocks : 1) and mica - smectite on volcanic glasses volcanic - depozit of complexes rocks. 2) smectite and chlorite-smectite, frequently triochtahedral regional metasomatic basic rocks. 3) highrothermolics of the volcanic countries with smectite and kaolinite-smectite. 4. These minerals are characterized by a high degree dispersity. At humidity appropriate to natural displays of the elementary particle are submitted by individual layers silicate type. In conditions subaeral type and in soils at repeated changes of humidity and temperature, including at passage through 0 - meanings PONmin is quickly irreversible change in the party of increase of the sizes of particles by processes histeresis of a type. PONmin, involved in a soil profile undergo a number of change. (a) In humus horizons of soils such as chernozem, sod-podzolic, gray forest etc. they cooperate with organic, including humic matter with formation more or less strong complexes making mikro-nanoscopic structure of aggregate conditional of horizons. (b) In intensive permazidic eluvial horizons PONmin intensively collapse and are partial taken out in illuvial part of a profiles, and also behind its limits. Thanking, high dispersity they have high ability to penetrate in cracks and pores of space of soils. A global type of horizons of destruction PONmin are eluvial horizons of podzolic, yellow-podzolic and red-podzolic soils actually humidic boreal, subtropical and tropical areas. In boreal conditions its display are concentrated in soils of plane-platformas regions, in subtropical-tropical - to modern and ancient mobile belts of the continental block. In subaridic and aridic areas boreal zone, in less measure in conditions aridic subtropics and tropics the process of a soil type transformation of particles of clay minerals and mixed-layer formations with smectite package in superdispersional condition formation is carried out. Such forms new-created PONmin are dated for areas of soda soils. They are formed in conditions diluted high alcoline solutions at escalating powerful environments of molecules of water around of natrium ions. The condition separated silicate layers promotes penetration into an interlayer of organic compounds, including fulvic type of humus. The map-scheme of geography of types PONmin in soilforming rocks and soils are developed. Poorly-ordered minerals are characteristic for ploughed soils. The downturn of intensity of reflexes of clay minerals with swelling structure in intensively used soils with application of organic and mineral fertilizers is caused not by destruction smectite phase, but low degree its ordering structure in c and a - b planes. It is caused by changes of acid-alkaline conditions, and also con-centration in soil solutions of potassium- and ammonium- ions , phosphate- and sulphate- ions, and also aggregation of particles at interaction with low-mobile elements - aluminium, iron and silicon and organic matter of diffrent types.

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