SPP 1090 AG 1: Physical stabilization of soil organic matter caused by formation of hydrophobic interfaces on aggregates and particles
Description:
Recently, it has become evident that soil water repellency is much more widespread than formerly thought. Small amounts of soil organic matter (SOM) can drastically alter the surface properties of single particles or soil aggregates, which may convert wettable mineral surfaces to water repellent surfaces. Generally it is assumed that hydrophobicity stabilize SOM by different mechanisms. It was found that the degree of hydrophobicity can serve as an indicator for the microbial degradation of SOM. Further, decreasing wettability has an considerable impact on physical processes. Strong hydrophobicity often leads to severe runoff and erosion, rapid leaching of surface applied agrichemicals. Knowledge of the wetting behavior of soils is further essential to describe the time-dependent variability of soil water content in the soil matrix which may lead to an extremly different physical and chemical environment for roots and microorganisms. This project is structured around three objectives. The first objective is to assess the degree of water repellency of aggregate surfaces and single grains. In this part the measurement of the contact angle, surface energies and surface charge should give a comprehensive characterization of the soils selected for the Schwerpunktprogramm. The second objective deals with causes of water repellency. It is planned to use soil solution originated from the sampling sites of the project in order to investigate their surface tension and their potential to modify the surface properties of soil particles and model surfaces, e.g. quartz plates. Finally the results of the characterization of the surface properties should be discussed with other projects focused on the analysis of the chemical composition of SOM.
Executive Institute:
Institute for Soil Science (IFBK) Details of Institute for Soil Science
Parent institution:
Leibniz University of Hannover Details of Leibniz University of Hannover (Lower Saxony)
Contract period:
01. 01. 2000 - 01. 01. 2008
Collaborative Project:
SPP 1090: Soils as source and sink for CO2-mechnisms and regulation of stabilisation of organic substance in soils Details of SPP 1090: Soils as source and sink for CO2-mechnisms and regulation of stabilisation of organic substance in soils
Funding Programme:
- DFG - Priority Programme Details of DFG - Priority Programme
Subject:
- Soil science
Purpose of research:
Basic research
Funding Institutions:
- German Research Council (DFG) (DFG) Details of (DFG)
Project Management Agency:
- German Research Council (DFG) (DFG) Details of DFG