Successive applications of cupric fungicides to grapevine can increase total copper concentration in the soil and modify its desorption in the soil profile. This study was carried out in 2006 in the soil chemistry and fertility laboratory of the Universidade Federal de Santa Maria to evaluate copper forms and desorption dynamics in Udorthent and Haplumbrept soils (in the layers 0-20 and 20-40 cm) under grapevine for 40 years and under successive applications of cupric fungicides. The soils were collected in the wine valley region of Bento Gonçalves, RS, in Southern Brazil. Udorthent samples were also collected (at 0-20 and 20-40 cm) in a forest near the vineyard and the data used as reference. Soil samples were dried, ground and sieved (2 mm), and copper was fractionated using the Tessier methodology (Tessier et al., 1979) and copper desorption with EDTA 0.05 mol L-1 pH 6.0, using the methodology of Fangueiro (Fangueiro et al., 2005). Results showed that the application of cupric fungicides to grapevine increases total copper and its available fractions, including in the 20-40 cm layer. The major part of copper of the soils cultivated with grapevine is retained in the mineral fraction, whereas under natural forest, organic matter is the main reservoir of the element. The greatest partion of copper, independent of the adsorbent material in the soils growing grapevine, is easily desorbable and can be considered of rapid equilibrium with the copper of the solution.
heavy metals; copper fractionation; kinetics; Vitis vinifera
