Variability of the foliar nutrient concentration of Alnus acuminata

Abstract

Variability of the foliar nutrient concentration of Alnus acuminata. The position of the samples in the canopy in A. acuminata trees of 3 and 5 years of age does not significantly affect the foliar concentration for most of the nutrients. The only exception is Ca in 5 year-old trees, whose concentration in the upper part was less than in the middle part of the crown. Although not significant, it was observed that the concentration of Fe, Mn and Zn tends to be greater in the external upper section of the crown at the age of 3; while the concentration tends to be higher in the external middle part of the crown at the age of 5. No significant differences due to age of plantation were observed in the foliar concentration of the nutrients from 2 to 8 year-old, in none of the compared seasons, except for the Mn, which tends to diminish with the age of the plantations (86 to 26 mg kg-1). The foliar concentration of Mg, Fe, Zn, Mn, Cu and B was higher during the dry season than during the rainy season, while the foliar concentration of N and P was higher during the rainy season and no variation was observed in the foliar concentration of Ca, K and S due to the sampling season. Based on these findings, the foliar critical levels for all elements analyzed in A. acuminata are presented.