Assessment of litter decomposition in temperate deciduous forest: A case study in Fruška Gora, Serbia

INTRODUCTION: Our study has been conducted as a part of the large scale decomposition experiment within the global collaborative network “TeaComposition initiative”. The aim of this initiative was to estimate short- to long-term plant litter decomposition rates by using standard protocols and substrates—commercially available Green tea and Rooibos tea with different decom-position rates—for comparison of the litter mass loss at numerous sites across various ecosystems worldwide. OBJECTIVES: The aim of our study was to test the effects of both litter type and land-use on litter decomposition in 3, 12, 24 and 36 months of incubation, by comparing the percentages of the tea mass lost. METHOD / DESIGN: The TeaComposition method (modified Tea bag method) involves measuring a tea bag before and after incubation in the field, and using the difference in weight as a measure of the organic material decomposed. The three localities chosen for our experiment corresponded to the three levels of protection regime established for the National park Fruška gora, with different management and treatments within the temperate deciduous forest. The guidelines of the standardized protocol of the “TeaComposition initiative” were followed throughout. Two homogenous plots were selected at each of the three sub- sites; two replicates of the two tea types were buried in the topsoil layer in each of the two blocks, resulting in four bags of each tea type per sub-site and sampling time. RESULTS: The values of the tea mass lost during all four incubation periods were higher for the Green tea than for the Rooibos tea. This pattern was expected because of the faster decomposition rate of Green tea due to higher content of non-lignified cellulose and of water-soluble compounds. Furthermore, the difference of the two tea types’ mass loss was the highest in three- months incubation. Our study has also shown no clear pattern regarding the values variation of the tea mass loss among three different plots; however, the highest level of variation was found for the Green tea in the longer incubation periods (24 and 36 months). CONCLUSIONS: These conclusions are in accordance with the results of previous research showing that, in the early stage of litter decom-position, the litter quality had the strongest influence on mass loss, whereas there was no significant effect of land-use or management practices. The microbial decomposition is carried out by many groups of microorganisms and is not limited by nutrients during the growing season. Still, differences in the litter mass loss among the land-use types increase in the later phases—as decomposition progresses—because of the decomposer groups being more selected, since fewer microbes possess the degradation enzymes for the remaining organic compounds. This pattern is clearer in Green tea, because Rooibos tea has much slower plant litter decomposition rate, due to high lignin content.