Logo of the Information System for Agriculture and Food Research

Information System for Agriculture and Food Research

Information platform of the Federal and State Governments

SPP 1315: Dynamic (redox) interfaces in soil - Carbon turnover in microbial food webs and impact on soil organic matter

Project

Environment and ressource management

This project contributes to the research aim ' Environment and ressource management'. Which funding institutions are active for this aim? What are the sub-aims? Take a look:
Environment and ressource management


Project code: DFG SPP 1315
Contract period: 01.01.2007 - 31.12.2010
Purpose of research: Basic research

In soils, much of the stabilized soil organic matter is associated to minerals, in particular to Fe oxides and hydroxides. Therefore, interaction of organic material with mineral surfaces has been suggested to be an important mechanism for soil organic matter stabilization. However, even if we assume a very large capacity of some minerals to adsorb and protect organic matter, there will always be a point when the mineral will be saturated with organic matter. Beyond that point, theoretically no further stabilization of organic matter can occur. However, what is observed is that at any time a certain percentage of the C input and turnover is stabilized by minerals. In fact, every microbial feeding cycle in soil results in stabilization of a certain amount of C. This cannot be explained if we assume that the mineral surfaces in soil are static, but we need dynamic, regenerating surfaces or have to consider non-surface-dependent processes. In soil, there are two important processes which contribute to the regeneration of interfaces. The first one is reductive dissolution and oxidative precipitation of Fe oxides and hydroxides. The second one is changing water content, which exposes the surfaces to different water tensions and thus modifies microbial activity on the microscale. Every change from anoxic to oxic conditions will create fresh surfaces which are able to adsorb and stabilize organic matter.

show more show less

Subjects

Advanced Search