Silicon fractions in Histosols and Gleysols of a temperate grassland site |
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| Authors: | Axel Höhn Michael Sommer Danuta Kaczorek Gisbert Schalitz Jörn Breuer |
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| Institution: | 1. Leibniz‐Centre for Agricultural Landscape Research (ZALF) e.V., Institute of Soil Landscape Research, Eberswalder Stra?e 84, 15374 Müncheberg, Germany;2. University of Potsdam, Institute of Geoecology, P.O. Box 601553, 14415 Potsdam, Germany;3. Leibniz‐Centre for Agricultural Landscape Research (ZALF) e.V., Experimental Field Station Paulinenaue, Eberswalder Stra?e 84, 15374 Müncheberg, Germany;4. University of Hohenheim, Landesanstalt für Landwirtschaftliche Chemie (710), Emil‐Wolff‐Stra?e 14, 70593 Stuttgart, Germany |
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| Abstract: | The importance of silicon (Si) in nutrition is currently being recognized by its beneficial effects on many crops. Therefore, it is important to determine the soil Si status and to examine different extractants for testing plant‐available Si. Little information is available about the Si status of Histosols and Corg‐rich Gleysols in temperate climate. This study was undertaken (1) to characterize different Si pools in Corg‐rich groundwater soils of an experimental site and (2) to study the influences of small‐scale variability on element distribution. At the experimental site, the thickness of the Corg‐rich layer ranges between 4 and 5 dm overlying fine‐sandy fluvial sediments. Four extractants were evaluated: 0.01 M CaCl2, 0.5 M acetic acid, 0.1 M sodium pyrophosphate, and 0.1 M Tiron (C6H4Na2O8S2 · H2O). Further, total element content was determined following HNO3/HF digestion. Calcium chloride–soluble Si shows no significant relations to other parameters analyzed. On the basis of published data, the soils investigated could be classified as Si‐deficient. The Si fraction extracted with acetic acid displays relations to Corg content of the soil and a weak correlation to CaCl2‐soluble Si, indicating that both solutions extract overlapping but not the same fractions. Sodium pyrophosphate extracts mainly organo‐mineral Fe and Al complexes in the soils studied, which is reflected in a highly positive correlation to Corg. Pyrophosphate‐soluble Si showed a negative relationship to Corg, which means a closer relation of this Si fraction to mineral matter than to Corg. The Tiron solution extracted most Si of all extractants, but this amounts only 1% of the total Si content. Taking into account the element‐specific relationship between pyrophosphate and Tiron‐extractable Fe, Al, and Si, it can be concluded that Tiron dissolves mainly the opaline silica present in Histosols and Corg‐rich Gleysols. The distribution of Corg and ash content shows clear spatial trend at the experimental site, which is correlated to pyrophosphate‐extractable as well as total Si. This small‐scale variability of soil parameters itself is related to a distinct microrelief. |
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| Keywords: | silicon Histosols Gleysols Si extraction methods |
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