EXTRAÇÃO E EXPORTAÇÃO DE NUTRIENTES PELO Eucalyptus grandis HILL ex-MAIDEN EM FUNÇÃO DA IDADE: 1 - MACRONUTRIENTES *

SUMMARY Leaves, stems plus bark and branches of E. grandis (Hill ex-Maiden) from one year up-to seven years old, situated on a soil type «latossol vermelho-amarelo, barro arenoso" (Orthox) belonging to the Champion Paper and Celulose Company at Mogi-Guacu, SP, Brasil, were collected. The materials were analyzed for N, P, K, Ca, Mg and S by conventional methods. The authors concluded: - The maximum dry matter yield occurs at the age of 6, 7 years old tree. - The maximum highest occurs with 7 years old tree and the maximum diameter (measured at 1.30 m from ground), after 7 years. - The leaves present the highest concentration of N, P, K, Mg and Sin all parts of the nutrients. - The maximum quantities of nutrients were detected at the following age of the tree: P -6.1 years; N, K, Ca, Mg and S -7.0 years. - The nutrients were extracted and exported by the tree at the following order: Ca > N > K > S > Mg > P. - Six years old tree accumulated more than 98% of the total P. - Among the nutrients Mg accounted for the highest exportation by the tree, succeeded by P > Ca > K = S > N. 1. INTRODUCAO Por se constituir uma essencia florestal de grande importância, o genero Eucalyptus tem merecido a atencao de diversos pesquisadores na area da nutricao mineral, principalmente nos paises onde essa especie e bastante difundida. Muitos autores sugerem as possibilidades economicas na exploracao dos solos de cerrado pela silvicultura, devido as condicoes que oferecem para minimizar os custos de