Fertilization during the establishment of a Eucalyptus camaldulensis plantation in the northern Brazilian Amazon = Aduba o no estabelecimento de um plantio de Eucalyptus camaldulensis na Amaz nia setentrional brasileira

Forestry plantations should be regarded as an alternative sustainable land-use system in degraded savannah areas. They contribute to the maintenance of productive processes in degraded soils that are of economic importance for local inhabitants; in addition, in the ecological sense, timber and non-timber products from planted forests reduce the exploitation pressure on native forests. Eucalyptus plantations on degraded savannahs in the northern Brazilian Amazon may help to reduce exploitation pressure on native forests. However, there is no information regarding the nutrients rates that would allow faster eucalyptus growth in that region. A trial was installed in an Yellow Latosol (Oxisol) soil type adopting a one-half-type fractionalfactorial design with four rates of N, P, and K. Functions were adjusted for the dependent variables height, diameter at breastheight (DBH), leaf tissue nutrient content, and soil-chemical attributes. Interaction N versus K was observed on tree heightwith a maximum of 7.8 m recorded at 200 kg ha-1 of N and 50 kg ha-1 of K. Phosphorus fertilization promoted greater DBH growth with maximum value at 120 kg ha-1 of P; however, the highest gain was obtained at 30 kg ha-1 of P. The NPK rates that maximized Eucalyptus camaldulensis growth were 200, 30, and 50 kg ha-1, respectively. Planta es de eucalipto, em áreas de lavrado degradadas na Amaz nia Setentrional brasileira, devem contribuir para diminuir a press o de explora o em florestas nativas. Porém, n o há informa es sobre as doses de nutrientes que permitem o rápido crescimento do eucalipto nesta regi o. Um experimento para avaliar a resposta à aduba o do Eucalyptus camaldulensis foi instalado em Latossolo Amarelo, adotando o delineamento fatorial fracionário com quatro doses de nitrogênio (N), fósforo (P) e potássio (K). Fun es foram ajustadas para as seguintes variáveis dependentes: altura, diametro à altura do peito (DAP), conteúdo de nutrientes nas folhas e atributos químicos do solo. Foi observada intera o NxK para a altura, com um máximo de 7,8 metros registrados com a dose de 200 kg ha-1 de N e 50 kg ha-1 de K. A aduba o fosfatada promoveu o maior crescimento do DAP com o valor máximo obtido com a dose de 120 kg ha-1 de P; O maior ganho, entretanto, foi obtido com a dose de 30 kg ha-1 de P. As doses de NPK que maximizaram o crescimento do Eucalyptus camaldulensis foram 200, 30 e 50 kg ha-1, respectivamente.