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Spatiotemporal dynamics of biogenic Si (silicium) pools in initial soils and their relevance for desilication
Project
Project code: ZALF-786
Contract period: 01.01.2013
- 31.12.2015
Purpose of research: Applied research
The
project has the objective to clarify the interactions between dynamics of
biogenic Si pools and desilication rates in transient state soil systems. This
will be the first attempt ever to quantify sizes and turnover dynamics of both
phytogenic and zoogenic Si pools in soils at the same time, together with the controls
acting on them. Starting with a characterization of soils’ initial state at
catchment scale we will analyze the annual SiO2 production of the
vegetation as a function of (i) spatial distribution of plant available Si in
soils as well as (ii) dynamics of invading Si accumulators. To do so we will
employ modern remote sensing techniques (UAV). After four vegetation periods,
changes in soils’ phytogenic Si pool will be compared to cumulative SiO2
production of Si accumulators by mass balance calculations. Using plot scale
manipulation experiments we will elucidate the influence of an increasing phytogenic
Si pool on desilication rates. At four sites annual Si exports via soil
solution will be determined under pure stands of both, Si accumulator and
non-accumulator plants. Plant SiO2
will be subjected to
dissolution experiments to yield mechanistic information necessary for the
development of algorithms to model observed desilication rates. The dynamics of
the zoogenic Si pool (testate amoebae) in soil will be quantified as a function
of plant pattern dynamics at catchment scale. For the first time, the attempt will
be made to quantify the zoogenic Si pool size by analyzing living and dead
amoebae with Energy-dispersive X-Ray Spectroscopy combined with Scanning
Electron Microscopy (SEM-EDX). The factors controlling testate amoebae
densities will be identified in plot and lab experiments. We will test the
presumed carbon, water / nutrient and Si limitation on amoebal growth at plot
scale using a completely
randomized block design. The influence of silica supply on testate amoebae
(idiosome growth) will be clarified in lab experiments under controlled
conditions (clonal cultures).
Section overview
Subjects
- Soil science
