Project Details
Projekt
Differentiating the roles of organic nuclei and mineral surfaces in the formation of soil microaggregates by exploring their elemental and isotopic label composition
Applicant
Professorin Dr. Ingrid Kögel-Knabner
Subject Area
Soil Sciences
Term
from 2015 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 251268514
With this proposal we aim to elucidate governing processes and mechanisms for the formation of soil microaggregates by analyzing the microspatial elemental/isotopic composition and the three-dimensional association of organic and mineral soil components at submicron resolution. We suggest that the different forms of organic matter that enter soils provide important nuclei for the formation of microaggregates leading to a compartmentalized architecture of aggregates. In a new incubation experiment we will therefore test the different mechanisms for microaggregate formation as initiated by different organic matter inputs that serve as organic nuclei, i.e. dissolved organic matter, particulate plant residues, or microbial necromass. We also intend to reveal soil microaggregate formation by applying our analytical approach to the natural soil materials from the loess pedosequence and the organic matter depletion field trial of the research unit. We will specifically focus on the analytical power of NanoSIMS to co-localize the sequestration/accrual of organic matter and minerals and quantify how it influences the heterogeneous soil microarchitecture. These spatially explicit data will be supplemented by bulk scale measurements, such as 13C-NMR spectroscopy to characterize the chemical composition of organic matter. The data collected will enable us to identify and quantify the contribution of distinct parts of the particle surfaces for the functions of soils for binding organic carbon, their water storage and transport function and as habitats for microorganisms. The developed identified mechanistic relationships will form an integral part of the quantitative model developed in the research unit.
DFG Programme
Research Units
