Assessment of availability of Cu and Zn by chemical extractor organic acids

Abstract

The evaluation of the availability of any plant nutrient begins with a selection of a proper extractor that must simulate as closely as possible the solvent power plants roots, is low cost, and does not present danger of contamination to the environment. However, the efficiency of an extractor is dependent on its composition and how it is employed for extraction methodology, and its validation is done by the significant correlation between soil extracted and the concentrations present in plants grown in the same. The aim of this study is to assess the availability of Cu and Zn to plants through chemical extractors organic acids and compare it to the DTPA, Melich-1. The experiments are conducted in a completely randomized design with four replications, 5 doses, and 2 soil types, totaling 40 experimental units for each experiment. Will be used two soils, medium loamy and sandy, collected in topsoil (0-20 cm) in Piracicaba-SP. For different concentrations of Cu and Zn in soil, apply 5 doses of each micronutrient in their experiments. Doses for both Cu and Zn are 0, 2.5, 5, 7.5, 10 mg kg-1, in the form of copper sulfate pentahydrate and zinc sulfate heptahydrate. The concentration of Cu and Zn available will be extracted with DTPA, Mehlich-1, and two solutions of organic acids. The statistical analysis will be performed using the statistical package SAS ® "Statistical Analysis System". Data will be submitted to analysis of variance and regression between the dependent variables (dry matter production of shoots and content of Cu and Zn in the plant) as a function of doses of Cu and Zn and content available Cu and Zn (DTPA , Melich-1, organic acids S1 and S2). (AU)