In Brazil, along with the expansion of clonal forestry, the management of more productive and more nutrient-demanding genotypes has led to the appearance of micronutrient deficiency symptoms, mainly of boron (B), and more recently, of copper (Cu) and of zinc (Zn), especially in Cerrado areas. The purpose of this study was to evaluate three extraction solutions to determine Zn availability (Mehlich-1, Mehlich-3 and DTPA pH 7.3) for eucalyptus seedlings grown in a greenhouse, on six Cerrado soil samples, and to assess the influence of soil properties on the efficiency of these extractors. The treatments were arranged in a randomized block design, with four replications, in a 6 x 5 factorial scheme, representing six soils and five Zn doses (0, 2.5, 5, 10, and 20 mg dm-3). The critical levels of Zn in Cerrado soils for eucalypts seedlings, by the extractors Mehlich-1 and DTPA, are 0.23 and 0.05 mg dm-3, respectively. The levels of soil Zn by the three extractants and the plant levels and content increased with increasing Zn doses and were highly correlated. Zn availability to eucalypt seedlings can be determined using any of the three extractors. However, Mehlich-1 is the most recommended. Firstly, due to the ease of handling compared to the other methods and, secondly, for being widely used in most routine analyses in laboratories of the country.
extractors; Mehlich-1; Mehlich-3; DTPA; fertilization
