Temperature effect on the rate of decomposition of peat-forming plants: results of a model experiment

Abstract

The decomposition of the prevalent peat-forming plants of oligotrophic bogs in the southern taiga subzone of Western Siberia is quantified in a model experiment. The decay rate (DecR) of Sphagnum fuscum, Chamaedaphne calyculata, Eriophorum vaginatum, and mixed sample (60% of Sph. fuscum and 40% of C. caltculata)is estimated as a C(CO2) emission from plant samples over 3 months at different temperatures (2, 12, 22° C) and at a moisture level corresponding to 60% of their water holding capacity. The dynamics of DecR of the prevalent peat-forming plants during the experiment is considerably influenced by both factors: the temperature and the type of plant litter. A remarkable increase in the C(CO2) emission rate is observed for all plant samples at the initial stages of decomposition. An increase in the DecR for all types of plants is observed first at 22° C and 1-2 weeks later at 2°C. During the 3 months of the experiment, the Sph. fuscum looses only 3-5% of the initial amount of C, whereas the C-losses from the C. calyculata and E. vaginatum vary from 6 to 18% depending on the temperature. The effect of plant species on the DecR is more pronounced and explains about 61% of the DecR variability. The temperature coefficient Q10 depends on the type of plant and varies from 0.97 to 1.3 in the low temperature range of 2-12°C and from 1.34 to 2.16 in the temperature range of 12-22°C.