Stabilization of organic matter by layer silikates - quality and turnover of interaction products

• Applicant: Professor Dr. Reinhold Jahn
• Subject Area: Soil Sciences
• Term: from 2000 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5247490

The overall goal of this proposal is to determine quantitative andqualitative relationships between carbon sequestration and clay mineralogy. The idea behind the project is that a extended period of fertilizer depletion combined with continued nutrient removal through plants will lead to changes in organic matter composition as well as to changes in the clay minerals assemblage (mainly through K-depletion in illitic materials). This in turn implies modifications in the physical properties as well as in the stability of the predominating clay-organic matter associations. We intend to investigate such changes on short, medium and long timescales. We will use experiments dating from 1902, 1956 and 1982. The overall goal will be devided in the following subgoals: a) which are the mechanisms behind the protective capacity of the mineral assemblage, b) what is the influence of clay mineralogy on stabilisation rates, c) how does theclay mineral assemblage influence proportion and type of organic matter associated with clay minerals, d) are there pathways from the pool of easily degradable organic matter into the pool of organic matter, that is stabilized through interaction with clay minerals, e) which rates of transfer are applicable here.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1090: Soils as Source and Sink for CO2 Mechanisms and Regulation of Organic Matter Stabilisation in Soils
• Participating Person: Professor Dr. Markus Kleber