Uni-Bayreuth grafik-uni-bayreuth



Dynamics of phytogenic silica in soil – plant system

Uta Beyersdorf1, Michael Sommer2, Yakov Kuzyakov1
1 Institut für Agrarökosystemforschung, Universität Bayreuth
2 Zentrum für Agrarlandschafts- und Landnutzungsformen (ZALF) e.V., Universität Potsdam

P 1.13 in Ecosystem Function

Phytogenic silica is one of the most active silica pools in terrestrial biogeosystems. Dissolution of phytogenic silica determines the output of Si from the soil to aquatic ecosystems, plant uptake of Si and is therefore important for silica cycle (Sommer et al. 2006).
This poster demonstrates the importance of phytogenic silica in the terrestrial Si cycle and summarizes methods of planned experiments to determine Si uptake by plants, formation, dissolution and leaching of phytogenic silica and the expected results.
The uptake of silica from different pools in soil will be quantified for characteristic deciduous trees, conifers and grasses and the formation of biogenic silica will be analyzed in experiments under controlled conditions. For investigations of Si uptake by plants germanium (Ge) will be used as tracer for Si. Kinetics of dissolution of phytoliths will be examined by incubation experiments under varying conditions of pH and redox potential. With percolation experiments lessivation and leaching of phytogenic silica will be investigated.
On two study areas with different geology and vegetation in the Black Forest (Baden-Wuertemberg), namely Seebach and Wildmooswald, litter and organic horizon will be sampled and Si contents will be analyzed. Then annual Si input from plant litter will be assessed and from sampled material phytoliths will be extracted which will be analyzed in further investigations. Microscope techniques will be applied to consider the amount, composition and morphological shape of phytoliths and their changes during dissolution.  

last modified 2009-04-01