TP14 Development of an Integrated
site analysis using non-invasive methods
There is an
increased awareness in soil science, that single non-invasive methods are
insufficient for a comprehensive characterisation of sites as they describe
only spatial variability of single soil properties. Following MCBRATNEY ET AL.
(Geoderma 117, 3-52, 2003), only 3 studies
exist worldwide at present (published in international, peer-reviewed journals)
coupling more than 3 non-invasive methods (partly confined to the field -
scale). Consequently there is considerable requirement in research,
particularly across field boundaries.
Even in these new approaches of “digital soil mapping” the influence of lateral
flux is disregarded in the majority of cases. With the exception of erosion
processes, systematic approaches are missing. Moreover, requirements in
research arise from analysing the temporal dynamics of spatial site
variability, which is caused by interaction between static site factors “soil”
and “relief” and dynamic external drivers such as “weather” and “management
practice”. Non-invasive methods – as
far as they map stable properties – describe the properties of the first 2 site
factors as time-invariant. This is comprehensible for properties as relief, clay
content etc, but not for their site relevance. As an example, the same soil
with high clay content may cause O2 deficiency in the root-zone of
plants in a wet year, whereas water deficiency is induced in a dry year. A
depression in the terrain with both, surface and subsurface lateral influx
enables high biomass production in dry years whereas lower biomass production
appears in wet years due to temporal O2 deficiency compared with
similar structured soils in flat terrain positions. Therefore geophysical methods and digital terrain analysis
require site interpretation from long-term observation. On the field scale
first approaches exist using multi-temporal remote sensing techniques, however,
these approaches have to be extended systematically in future to larger areas
and various natural landscapes.
The main
task of the subproject is the development of an integrative site analysis in
the selected research areas under practical conditions. We focus on three
single objectives:
1. The
development of a rule-based expert system for mapping site variability in space
and time using different non-invasive methods.
2. The development of a simplified methodology to identify areas with potential
lateral flux (source- and return flow areas)
3. Defining site types using a hierachical rule-type (in close collaboration
with TP 15, 16 and 23)