Soil properties and rate of organic matter decomposition in riparian woodlands using the TBI protocol

This study deals with the decomposition rates of two types of commercial teas (green and rooibos) using the protocol proposed by Keuskamp et al. (2013). The tea bag samples were distributed at 60 sites along two major rivers (Coaticook and Massawippi) in south-central Quebec (Canada). The sampling sites were distributed in keeping with two separate zones: flood zones (FZ) (interval recurrence of 0-20 years) and no-flood zones (NFZ). Several soil and environmental parameters were included in the analysis of the tea bag samples, including soil acidity, total organic carbon and total nitrogen content, texture, litter thickness (cm), drainage and topography. The green tea samples were found to decompose twice as fast as the rooibos tea samples under similar soil and environmental conditions. The remaining green tea mass showed average values of 23 and 34% for the FZ in the Coaticook (COA) and Massawippi (MAS) areas, and 32 and 30% for the NFZ in the same two areas. The average values for the rooibos tea samples were 62 and 60% (FZ), and 62 and 61% (NFZ), respectively. The decomposition rate (k) and stabilization factor (S) for the tea bag samples are comparable between zones (FZ and NFZ) and between areas (COA and MAS), with values ranging from 0.020 +/- 0.01 to 0.030 +/- 0.01 g.g(-1).day(-1) (k), and from 0.165 +/- 0.08 to 0.218 +/- 0.05 g.g( -1) .day(-1) (S). Based on the results obtained, the S and k variables were not correlated with any soil and environmental variables, and the statistical analyses did not yield any significant differences (p-value 0.05). By grouping various soil and environmental parameters with the analysis of the decomposition of the tea bag samples, these parameters were seen to have little influence, and the nature of the organic compounds (higher or lower litter quality) appears to be the main factor in determining the decomposition rate.