Considerable uncertainty remains on the decomposition dynamics of plant litter and thus in the estimates of CO2 emissions from this litter pool. Harmonized data obtained from standardized litter experiments would provide a key prerequisite for further developing simulation models for the estimation of the C balance of ecosystem litter pools. Moreover, a tea bag approach would enable high-resolution decomposition measurements in space and time, which would provide unique data for calibration and up-scaling to ecosystems and for modeling efforts enabling a more accurate quantification of litter decomposition processes. Existing models to simulate C cycling in litter and soil (e.g., C-Tool, Century, RothC , or Yasso ), typically differ in the representation of decay processes as, for example, in the extent of representing litter quality. The models were also developed for use in different ecosystems and at different scales. Based on concurrent application of different models to simulate the decomposition of standardized litter, it would be possible to identify the significance of the underlying model assumptions and of knowledge gaps. Such model comparisons could also be used to strengthen the confidence in model estimates. A robust comparison between models is still difficult because suitable data are lacking to examine the role of process-detail for model predictions; hence obtained data through the TeaComposition initiative together with the data on the local litter decomposition would provide an excellent basis for it.
First tests have been done with the Yasso model. Other models are also encouraged to join.
Yasso -soil carbon model
A dynamic model to calculate the amount of soil carbon, changes in soil carbon and heterotrophic soil respiration. http://en.ilmatieteenlaitos.fi/yasso
Contact: Jari Liski