Project Details
Projekt
Dichotomy of gluing and cementing agents in soil microaggregation
Subject Area
Soil Sciences
Term
from 2015 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 251268514
The identification of mechanisms in soil microaggregation is only possible by linking the surface chemistry of involved components to the formation and properties of microaggregates. We aim at identifying the role of different aggregate-forming agents (organic matter, clay minerals, metal oxides) involved in microaggregate formation and stability. For this, we will investigate the formation and temporal and spatial change of physicochemical properties of microaggregates (20-250 ¿m) and their building units (<20 ¿m) in a series of batch and microcosm experiments as well as in a soil toposequence. Our basic analytical approach relies on X-ray photoelectron spectroscopy (XPS) of microaggregates to determine the elemental composition of inorganic and organic surfaces. The microaggregate surface chemistry (XPS), morphology (scanning electron microscopy), particle and pore size distribution (laser diffraction, Hg porosimetry, gas adsorption), as well as wettability (contact angle analysis) will be related to the stability of microaggregates. Consequences of changing environmental conditions to microaggregate stability will be assessed upon selective removal of aggregate-forming agents via microbial reduction of FeIII oxides, organic matter mineralization, and pH shifts. These studies will provide a mechanistic background for modeling microaggregation with relevant implications for soil organic matter stabilization.
DFG Programme
Research Units
Subproject of
FOR 2179:
MAD Soil - Microaggregates: Formation and turnover of the structural building blocks of soils
Co-Investigator
Dr. Klaus Kaiser
