Plant litter decomposition in agro-ecosystems: a functional study on the effect of resource history, chemical composition of plant litter and the dynamics of the microbial community.

Abstract

Microbial decomposition of plant litter is of vital importance to agricultural ecosystems because it facilitates nutrient cycling in soils. The functional dynamics of the microbial community and their interaction with plant substrate chemistry are poorly understood. In the majority of global carbon models, soil communities are assumed to be functionally similar with regard to decomposition. The underlying idea is that a high degree of functional redundancy is present in microbial systems due to high species richness, rapid adaptation and physiological flexibility. However, this idea has recently been challenged. It is now considered likely that microbial communities are functionally dissimilar. However, the mechanisms by which these differences arise are not yet clear. Among the possibilities are local adaptation of communities or differences in overall ability, which implies that some soils are simply more active than others. This insight calls for research to clarify the interaction between soil microbial community and plant litter composition to provide better estimates for carbon models. Research questions that will be addressed are:

1) Are soils functionally dissimilar?

2) Is home field advantage or ability the driving mechanism for differences in litter degradation between temperate soils?

3) At what time scale does local adaptation occur?

The project is innovative as the interaction between the microbial community and plant litter chemistry in artificial soils has not yet been studied. Moreover, the use of state of the art methods like shotgun – mRNA metatranscriptomics and pyrolysis-molecular beam mass spectrometry will provide a high resolution insight in plant litter decomposition dynamics.