Release of plant nutrients from decomposing leaf litter in a South Swedish beech forest

Abstract

Weight loss and dynamics of plant nutrients (N, P, K, Ca, Mg, S, Fe, Mn, Na, Zn and Cu) in leaf litter were studied in a mature beech forest in South Sweden, using the litter bag technique. An initial decomposition period of about 12 to 18 months was characterized by an absolute net increase of N, P, and S contents in litter, followed by a period of net release of these elements. This development, which was most obvious for N and P, was interpreted as a change from a phase where decomposer activity was limited by the availability of nutrient elements to an energy‐limited phase. A net release of nitrogen did not occur until after two years of decomposition, and a transfer of nitrogen and phosphorus between different litter layers is here proposed to work as a retention mechanism.Potassium and sodium were quickly leached from the litter, while release of magnesium, calcium, and initially also manganese, was more associated to organic matter weight loss. Iron, zinc and copper were all strongly accumulated in the litter material. This is explained by mineral soil admixture for the former element and by atmospheric fall‐out in combination with the chemical complex formation character for the latter two elements.Finally, the importance of the different release processes in the total nutrient recycling of the forest is discussed.