Effect of Application of Zinc on Seedlings of Eucalyptus urophylla

Abstract

Eucalyptus represents a species with consolidated cultivation in the Cerrado and that has been cultivated in several states that cover this Biome. Thus, the objective was to evaluate the growth and development of Eucalyptus urophylla seedlings in response to soil and foliar zinc application in a Cerrado Red Latosol. Two experiments were set up in a completely randomized design, with five treatments and seven replications. The first experiment consisted of five doses of Zn, in the form of zinc sulfate for both experiments, 0; 2.5; 5; 10 and 20 mg/dm³ applied via soil and the second experiment consisted of five doses of Zn, 0; 2.5; 5; 10 and 20 mg/L applied via foliage plus an extra dose of 20 mg/dm³ of Zn applied via soil, this dose being necessary due to the low zinc content in the soil and which could compromise the initial development of seedlings that would receive applications via leaf. The experiments were carried out in a greenhouse and after 80 days of planting, the following were evaluated: stem diameter (neck), height, root length, number of leaves, shoot and root dry matter, total dry matter, of macro and micronutrients in leaves and gas exchange: internal carbon concentration, stomatal conductance, transpiration and net photosynthesis rate. Even though Eucalyptus urophylla seedlings did not show statistically significant differences, part of the evaluated variables showed a positive response to the application of zinc, analyzing the linear and quadratic regression graphs, mainly at doses of 10 and 20 mg/L and 10 and 20 g/dm³.