Open access publications in the SLU publication database

Abstract

Effects of temperature history on litter decomposition was evaluated with the Q-model calibrated to a needle litter incubation experiment and using the GLUE modelling framework. The needle litter incubation was a full factorial design with initial and final temperatures 5, 15 and 25oC. Samples going to a different second temperature were moved when approximately 12% carbon had respired. We used four variations of the Q-model; the combination of one or two initial litter quality values and fixed or temperature-dependent decomposer efficiency. The model was calibrated to the constant temperature subset of the data. Evaluated against the subset containing temperature shifts, gave good results, except just after the change in temperature where the model predicted less than measured. Using one or two initial litter quality values and fixed decomposer efficiency had little effect on litter quality and respiration during the final incubation temperature. When the decomposer efficiency was allowed to vary with temperature, the best predictions had decomposer efficiency values that decreased between 5 to 15oC and did not change between 15 and 25oC. Having flexible decomposer efficiency resulted in substantial differences in litter quality between the three temperatures at the end of the initial incubation. This resulted in that samples at the same final temperature, subjected to different initial temperatures, decomposed at significantly different rates. The result suggests that it might be important to consider other factors than the variation in temperature sensitivity with quality when evaluating effects of temperature changes on soil organic matter stability.