CAPACITY OF THE EXTRATION METHODS AND BIOAVAILABILITY OF ZINC FOR CULTURE OF THE MAIZE CULTIVATED IN EUTROPHIC YELLOW RED ARGISOL

Abstract

Increasing grain yielder, with reduction of costs, depends currently on the use micronutrients as complementation of the conventional fertilization. In this study two chemical extractors were tested (Mehlich-1 and DTPA), in the extration of Zn available in eutrophic Yellow Red Argisol, besides verifying amount of this metal in the foliate fabric of maize cultivated in this soil, with application of
different doses of Zn under different treatments with NPK. The experiment was lead in the city of Palotina - PR (September/2002 - January/2003), in a randomized block delineation, with four replication. The treatments had been made in constituted factorial project of three forms of fertilization NPK: without fertilization (check); one time the recommendation of fertilization for the culture of the maize and the double of the recommended dose of fertilization. The sources of P, K and Zn in the base had been phosphate bicalcium potassium nitrate and zinc sulphate, respectively. The used doses of Zn were: 0,0; 5,0 and 10,0 mg dm-3. For chemical analysis, it was collected 10 leaves for parcel in a total of 36 samples, and also soil samples in the line and space between lines, totalizing a total 72 samples. The determination of N, P and K were accomplished to methodology of the IAPAR, and the determination of Zn was accomplished by digestion nitro-peroxide and techniques of spectrometry of atomic absorption of flame. The extractors used for determination of amount of Zn in the soil are the Mehlich-1 and DTPA, being that both had demonstrated a good correlation among the present amount in the soil and its bioavailability in the foliate fabric of the maize.