Productividad aérea y ciclo de nutrientes en plantaciones de Pinus Taeda l. en el norte de la provincia de misiones, Argentina

aboveground net primary productivity (anpp), nutrient cycling and nutrient use efficiency (nue) were estimated for three 20 years-old pinus taeda l. experimental plantations in the north of the misiones province, argentina. anpp was 34.8 ±1.5mg·ha-1·yr-1 and litterfall was 16 ±1.1mg·ha-1·yr-1. mean annual bole increment was 20% higher than the mean for commercial plantations of misiones and near the upper limit of the range for tropical and subtropical pine plantations. carbon requirement and uptake were 18 and 16mg·ha-1·yr-1, respectively. the requirements of n, p, k, ca and mg were, respectively, 298, 15, 63, 70 and 15kg·ha-1·yr-1. uptake was 161, 8, 36, 70 and 15kg·ha-1·yr-1, respectively. the requirements were allocated mainly to leaves and bole. the nutrient return represented ~70-90% of annual uptake. the leaf resorption efficiency of n and p was ~40%, and that of k ~44%. proficiency of n and o was complete. the nutrient use efficiency (nue) for n was higher than in tropical forests. compared with pine plantations on less fertile tropical soils, the plantation from misiones showed higher anpp and nutrient uptake and return, but lower nue, especially of n and p. despite the fact that p is potentially limiting, this was not evident in the studied plantation probably because organic matter and nutrient legacy from the previous humid forest supplied the first rotation plantation with the initial nutrient needs and fast decomposition of litter continued this supply.x653