Thesis subject

Assessment and modelling the interaction between nitrogen inputs and carbon sequestration in agricultural and natural ecosystems

The Environmental Systems Analysis Group provides the possibility for students to do their thesis in collaboration with our group. This is one of many possible thesis subjects. Please feel free to contact professors De Vries or Kuijper (right) for more information.

A very important driver, whose impacts on C sequestration is still rather controversial, is nitrogen (N). In natural systems (especially forests), retarded below-ground carbon cycling in response to N addition seems the general rule thus leading to N induced increases in (soil) C sequestration. There are also conditions under which N addition accelerates decomposition and soil respiration, thus decreasing soil C sequestration, such as forest with severe N limitation or inversely strong N saturation, but this seems to be a minority of the systems. In agricultural systems, however, the impact of N inputs on soil C sequestration is less clear. There are datasets indicating an increase in soil C in agricultural soils in response to inorganic N fertilizer addition, but the reverse has also been claimed. Until now the impact of N on soil C sequestration by agricultural soils is unresolved, and the same holds for the mechanisms behind the effect of N addition on C turnover processes.

The aims of MSc theses related to this topic are to:

  1. give an overview of current insights on the effect of nitrogen deposition on soil carbon sequestration, specifically with respect to carbon decomposition (soil respiration),
  2. collect and evaluate datasets that can be used to assess interacting impacts of N on soil C sequestration,
  3. (iii) further improve current models for soil chemistry and carbon sequestration by including new insights in soil microbiology into these models, model validation on existing datasets and application of the model on a regional scale.