Eficiência de utiliza??o de nutrientes e sustentabilidade da produ??o em procedências de Eucalyptus grandis e Eucalyptus saligna em sítios florestais do estado de S?o Paulo

摘要

Nutrient use efficiency and growth of three provenances of Eucalyptus grandis and three of E. saligna were evaluated, at 78 months of age, on various sites located in the counties of Angatuba, Itapetininga, Paraibuna, S?o Miguel Arcanjo and S?o José dos Campos, in the state of S?o Paulo, Brazil. There was a variation in biomass production among sites, with the highest yield being obtained in S?o Miguel Arcanjo, followed by Paraibuna. The other counties constituted a third group. The genetic materials revealed variations in nutrient use efficiency from site to site. E. grandis showed greater N, P, and Mg nutrient use efficiency than E. saligna. There were no appreciable differences in efficiency between the two species for Ca and K. High nutrient use efficiency is not necessarily related to high productivity. Ca and K are the nutrients that could most limit productivity of the next rotation, when harvesting the stem. However, this limitation can be substantially reduced, especially for Ca, if only stemwood is harvested.