Abstract:

Aims Estimation of ecosystem carbon balance may be affected by timing of sampling. Our objective was to determine the effect of different incubation starting times on litter decomposition rate (k) in a tropical and subtropical forest.
Methods We used litter bags and incubated them in the field at the same site beginning on eight different starting times over a year, beginning January 13 and at 45-day intervals. Each of the eight sets of litter bags was sampled four times over a period of 12 months, remaining litter mass was determined and k values were estimated. Temperature, precipitation, photosynthetically available radiation, soil water content and relative humidity were measured throughout the experiment.
Important findings The remaining litter mass and k values were significantly different (p < 0.05) among the eight starting times. Rate of litter decomposition was significantly (p < 0.05) correlated to temperature and precipitation during the early phase rather than the later phase of the experiment. The k values ranged from 0.78 to 1.30, and were significantly higher (p < 0.001) for litter whose incubation started in the wet seasons as compared to the dry seasons. Therefore, time for the start of incubation may significantly influence estimation of k values, which in turn may influence estimation of ecosystem carbon balance.

Key words: environment factor, incubation time, litter decomposition constant k, litter decomposition, subtropical forest