Changes in nutrient and fibre content of decomposing Phragmites australis litter

A litter bag experiment was performed in a healthy and a die-back reed stand of Lake Ferto/Neusiedler See. Mass loss, hemicellulose, cellulose, lignin, C, N, S and P concentrations of Phragmites australis leaves and culms were determined. Leaves decomposed faster than culms at both sites. After 33 months 82-90% of the leaf and 39-43% of the culm mass was lost, corresponding to a fibre loss of 82-90% and 32-35%, respectively. The N, C and S concentrations increased as decomposition proceeded, while the P concentrations decreased. The decaying coefficient model gave the best fit of the mathematical models tested (single exponential, decaying coefficient and composite exponential model). No significant differences in decomposition rates were detected between the two sites.