Chemical extractors on copper phytoavailability evaluation in soils from the state of Paraná

Abstract

Chemical extractors behaviors were evaluated in soils which received copper manuring, according to two essays with soybean and corn as testing plants in greenhouse. The experimental design was completely randomized with three replications. The treatment consisted of three doses of Cu (0.0, 2.5 and 5.0 mg.dm^-3) used in CuSO₄.5H₂O solution. The extractor solutions were Mehlich 1 (HCl 0.05M+ H₂SO₄ 0.025M), EDTA 0.005M and DTPA 0.005M-TEA at pH 7.3, so that copper contents in those soils and plants were determined by atomic absorption spectrometry. The extractors evaluation was done considering linear regression among copper contents in plants dry matter and in soils. In both cultures the DTPA 0.005M-TEA at pH 7.3 showed higher superior coefficients of correlation in relation to the other extractors, revealing itself as the best extractor to evaluate copper phytoavailability in these studied soils.