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Gewählte Master / Diploma Thesis:

Elena Cocuzza (2017): Silicon availability in Lower Austrian topsoils.
Master / Diploma Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 61. UB BOKU obvsg FullText

Data Source: ZID Abstracts

Abstract:: Silicon is an important plant nutrient involved in alleviation of multiple stresses. Globally increased export of silicon with harvest has raised concerns about Si depletion in cultivated soils. We determined CaCl2-extractable (potentially plant available) and NaOH-extractable (amorphous) silicon in Lower Austrian topsoils under arable and grassland use in Lower Austria. To this end we re-sampled 95 sites for which archived soils collected between 1986 and 2000 are available. Using multiple linear regression models we show that the plant available silicon concentrations in archived non-calcareous soils are positively related to pH and clay content, and negatively with organic matter. In calcareous soils plant-available silicon was negatively related to organic matter, sand and silt content. While we found no model explaining the amorphous silicon fraction in non-calcareous soils, this fraction was related negatively to organic matter, sand and carbonate content in calcareous soils. The amorphous silicon fraction increased with the advance of soil formation, as we measured higher concentrations in more developed soil groups. Plant-available silicon showed a similar pattern, however, lower values for the most developed, more acidic Cambisols and Umbrisols. The medians of the amorphous silicon fraction were similar in archived (2730 mg kg-1) and re-sampled (2620 mg kg-1) soils, with no relevant difference between soil use. The medians of the plant-available silicon concentrations were 29.0 mg kg-1 in archived, and 20.5 mg kg-1 in the re-sampled soils, with lower concentrations in grassland as compared to the arable soils. The fraction of soils below the suggested critical value for plant-available silicon (20 mg kg-1) increased from 39 % in the archived to 47% in the re-sampled soils. We conclude that a substantial, increasing proportion of Lower Austrian soils is depleted of plant-available silicon, possibly requiring fertilization and/or changes in management.; Beurteilende(r): Wenzel Walter; 1.Mitwirkender: Puschenreiter Markus