Project Details
Projekt
Coordination Funds
Applicant
Professor Dr. Kai Uwe Totsche
Subject Area
Soil Sciences
Term
from 2015 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 251268514
Within the soil aggregate system, microaggregates are supposed to be of primary importance, as they are linked with essentially all processes which control interaction, transport and turnover of soil constituents. As such, they are intimately connected with energy and biogeochemical cycles. During pedogenesis, microaggregates are formed by a complex interplay of physical, chemical and biological processes. Although soil functions are to a large degree controlled by the formation of an aggregate structure, still very little is known about the rates and controls on microaggregate formation in space and in time. Yet, this knowledge is mandatory to link the microarchitecture of soils to fluid flow and transport, activity of microorganisms, turnover and interactions of elements, as well as to the stability of the microaggregates themselves. The grand goals of this research unit (RU) are to gain a model-based mechanistic understanding of the formation, build-up, composition, properties and stability of these basic soil structures and to relate that to fundamental target functions of soil: habitat, carbon sink and water-storage. Our objectives are the exploration and the quantitative characterization of the composition, the microarchitecture, the stability, and the properties of microaggregates with a unique combination of high-resolution imaging and analytical techniques. Thus, the RU is organized in different projects that provide the complementary and specific elemental, chemical, physical, topographic and mechanical information on the soil microaggregates at the micron to submicron scale with overlapping scale ranges. We expect that a major advancement of the mechanistic understanding of the target functions of soil will derive from the concomitant application of the above-mentioned techniques to both soil microaggregates isolated from a soil texture toposequence - in the second phase additionally a chronosequence - or collected from a so far unique multi-stable-isotope labeling microcosm experiment. The labeling experiment is designed to explore simultaneously the role of mineral and organic matter key components and key - actors - in the formation of soil microaggregates. Our experimental work are integrated by an explicit modeling approach on the continuum scale which will be used not only to - model the measurable - but to test already existing and newly developed theories and to quantitatively analyze the data-based theoretical concepts of soil microaggregate formation, stability and turnover. In this proposal we present the central coordination tasks of the RU and how we plan to accomplish these. These tasks comprise joint sampling campaigns, the central microcosms experiment, the provision and production of labelled compounds, the joint development and harmonization of protocols for microaggregate separation and isolation, the joint modeling and interpretation endeavor, the data handling strategy, and the dissemination of results.
DFG Programme
Research Units
