Nutrient dynamics in decomposing litter of three pine species in a Corsican Mediterranean pine forest

The dynamics of the nutrients, N, S, P, K, Ca, Mg, Mn, Fe, Zn, Cu, during the decomposition of litters of Corsican pine (Pinus lancio Poiret), Stone pine (P. pinea L.) and Scots pine (P sylvestris L.) incubated in a Corsican pine forest in South Italy Apennines was studied over two years and half with the aim to evaluate how the quality litter affects nutrient release. The concentration and absolute amount of N, P, S and Fe increased during the decay and a positive correlation was found between the concentration and the accumulated mass loss in all three litter types. By contrast, the three litter types showed different dynam¬ics for K, Ca and Mg; the initial concentration of these elements determined, at least in part, the rate of release or immobiliza¬tion. Manganese accumulation was recorded in Stone pine litter which had the lowest initial concentration, whilst this element started being released since the onset of decomposition in Corsican and Scots pines litters. No relationship was found between mass loss and Zn concentration. An increase of Cu concentration, positively correlated to accumulated mass loss, was observed in Corsican and Stone pines litters. Even if N, S were always immobilized suggesting that they were required for microbial growth, nevertheless, these element were not the major factor limiting decomposition. In fact, other elements less mobile like Fe and Mn for Stone pine litter, Fe, P and Cu for Corsican pine litter and P and Fe for Scots pine litter limited.