Sintomas de deficiência de macronutrientes e de boro em clones híbridos de Eucalyptus grandis com Eucalyptus urophylla

Abstract

To characterise symptoms of macronutrient and boron deficiencies in hybrid clones of Eucalyptus grandis with Eucalyptus urophylla, a trial was conducted using nutrient solution, with treatments including complete solution and minus N, minus P, minus K, minus Ca, minus Mg, minus S and minus B with four replicates. Descriptions of the symptoms were made monthly, 4 months after the establishment of the treatments. Samples of leaves were collected to determine nutrient concentrations, taking the fifth and sixth leaf as standards, counted from the tip of the branches in both upper and lower parts of the crown. Another sampling was performed, collecting only leaves with deficiency symptoms, for N, P, K and Mg using old leaves and for Ca, S and B young leaves. The sequence of symptoms appearance was N, P, B, K, Ca, Mg and S. Nutrients concentrations in leaves of treatments with omitted nutrients were lower as compared to leaves of the complete treatment, indicating that the symptoms described were really due to the deficiency effect. The nutrient concentration of leaves with high symptoms was smaller than those for the fifth and sixth leaves, except for calcium. Eventhough, these leaves appeared to be adequate to predict nutritional deficiencies in Eucalyptus. The highest intensity of symptoms occurred for boron and the lowest for sulphur.