Nutrient accumulation in Eucalyptus bark at different population densities

Acúmulo de nutrientes na casca de Eucalyptus em diferentes densidades populacionais

ABSTRACT

The objective of this study was to quantify the accumulation of nutrients in the bark of four eucalyptus clones at 12 years-of-age, planted at different population densities, and the values were extrapolated to kg of nutrients per hectare. The experiment used randomized blocks in a 4 × 3 factorial design and three replications, with four Eucalyptus clones (2486, I182, I144, and GG100) planted at three population densities (416, 833, and 1111 trees ha^-1). The rigorous cubage of three trees per plot was performed by collecting discs of bark at the following heights: diameter at breast height (1.30 m), 0, 25, 50, 75, and 100% of the commercial height of the stem. The bark discs of each tree were grouped and used to determine N, P, K, Ca, Mg, and S content, in addition to the basic density. The volume and dry mass of bark per tree was estimated and the accumulation of nutrients per tree ha^-1 was estimated sequentially, for each population density. Analysis of variance and Tukey’s post-hoc tests verified that Ca showed the greatest accumulation in the bark, followed by N, K, S, Mg, and P. The increase in population density contributed to higher bark production and greater nutrient accumulation per hectare. However, this increase was not evident when comparing densities of 833 and 1111 trees ha^-1.

Key words:
compartmentalization; nutrient cycling; spacing