- Root decomposition

Root decomposition

Fine roots represent a large fraction of annual primary productivity especially in grasslands and their decomposition may account for up to 53% of total plant tissue turnover. However, only about 2% of studies on decomposition included roots, not to mention in the context of plant diversity. Plant species composition and diversity could affect root decomposition in various ways, e.g. through roots of different quality and/or by providing different biotic and abiotic decomposition habitats.

In our study, we aim to evaluate the overall effect of plant diversity on fine root decomposition in grassland and to further disentangle the effects into those of root litter quality and more general effects of changing biotic or abiotic environmental conditions.

Our hypotheses are:

  1. Root litter quality decreases on average over the plant species richness gradient and
  2. Environmental conditions favor higher decomposition with increasing plant richness due to increasing soil moisture and increasing decomposer diversity and abundance.

The experiment is conducted in the frame of the Jena Experiment in Jena, Germany. The plots are of 6 plant species richness levels (1, 2, 4, 8, 16, 60 species) combined with 4 functional group richness levels (1, 2, 3, 4 functional groups).

Our study includes three sub-experiments using a litter-bag approach:

  1. Decomposition of plot specific roots in their origin plots
  2. Decomposition of standard roots (Lolium perenne) in all plots
  3. Decomposition of plot specific roots in a common-garden land

Root morphological and chemical traits are measured with WinRhizo and Near-infrared spectroscopy (NIRS), respectively. In addition, plot specific environmental factors (e.g. soil moisture, soil temperature and soil nutrient concentrations) are monitored and composition of soil fauna as well as microbes are analyzed in other projects in the Jena Experiment. This study is part of SP6 Root Turnover. This work is performed by Hongmei Chen.

letzte Änderung: 01.04.2015