A study of the development of agric horizons in Quebec soils
| Autor: | Seddyk, Esam Abdul-Sattar |
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| Jazyk: | angličtina |
| Rok vydání: | 1979 |
| Předmět: | |
| Druh dokumentu: | Electronic Thesis or Dissertation |
| Popis: | Pan layers have been observed in profiles of humo-ferric podzol soils of the St. Lawrence Lowland region (Quebec, Canada). Physical, chemical and mineralogical studies were conducted on four selected profiles, three cultivated, and one non-cultivated, in order to assess the influence of cultivation in the development of an agric horizon. The non-clay fractions (2-0.02 mm) of the parent material contained chlorite, mica with feldspar and quartz as the predominant light minerals, hornblende, pyroxenes, olivines, epidote, magnetite, ilmenite, anatase and rutile in the heavy mineral fraction. The fine silt (2-20 (mu)m) and clay (< 2 (mu)m) fractions of the sandy parent material contained primarily quartz, feldspars, chlorite, mica and hornblende minerals. During soil development and formation of agric horizon these minerals underwent weathering at different rates and to different extents. In the fine silt fraction, weathering seemed to occur mostly by fragmentation of particles. In the clay fractions of the cultivated profiles, the phyllosilicates successively formed irregularly interstratified minerals with contractible and expandable vermiculite and smectite but less so in the non-cultivated soil profile. The mineralogical composition of the agric horizon consisted of the non-expanding minerals, with a predominance of illite and chlorite. The release of iron and/or aluminum hydroxy materials resulting from weathering of silicate minerals, and their translocation in the form of organo-metal complexes to where they precipitated due to ionic concentration effects, contributed to the formation of the agric horizon. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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