Abstract
The purpose of this study was to evaluate Cu and Zn migration and fractions in sandy soil of vineyards. In Urussanga (SC), Brazil, soil samples were collected from a 4-year-old and 15-yearold vineyard, and from a forested area. In the soils, the chemical characteristics of Cu and Zn were analyzed by the EDTA method, which determines the fraction available in soil; 3050B method of the USEPA for total concentrations, which represents the pseudosoil contents in the soil; and chemical fractionation, which estimates soluble fraction, exchangeable fraction, fraction associated with clay minerals, fraction associated with organic matter and residual fraction. The results show that there is accumulation of Cu and Zn in sandy soils cultivated with grapevines and with frequent fungicide applications. These higher levels were found in soils with longer cultivation time (15 years old), but were restricted to the superficial layers of the soil. Most of the Cu was extracted by EDTA method, and it may be considered as available to plants. The EDTA also extracted a small part of Zn. Most of the Cu in the vineyard soils can be characterized by low geochemical mobility, but in the uppermost soil layers of the oldest vineyard, there was an increase in Cu content associated with soil organic matter. Most of the Zn in the vineyard soil was associated with minerals, which indicates low mobility and also low potential for toxicity to plants and microorganisms. Key words: availability, chemical fractionation, toxicity, environmental contamination, Vitisvinifera.
Highlights
In the southern region of Santa Catarina (SC), Brazil, vineyards are planted on soils located on lands near sea level with sandy texture, predominance of 1:1 clay, low organic matter content, acidic soil and low natural fertility (Schmitt et al 2013)
Copper and Zn in the soil are retained by physicalchemical bonds and their lability depends on the ligand, especially on the content of minerals, oxides and hydroxides of iron (Fe), aluminum (Al) and manganese (Mn), carbonates and organic matter (Bradl 2004; Couto et al 2015), and on the soil pH value (Chaignon et al.2003; Shaheen et al 2015), cation exchange capacity (CEC) and the composition of the organic matter (Fernández-Calviño et al 2010)
In vineyard 1 (4-year-old), ZnEPA levels at the 0.10 to 0.40 m layers were higher than those observed in vineyard 2 (15-year-old). This can be attributed to the longer history of Zn fungicide application on grapevine leaves and from poultry waste application used as source of N, P and K in fertilization and grapevine production (FernándezCalviño et al 2012)
Summary
In the southern region of Santa Catarina (SC), Brazil, vineyards are planted on soils located on lands near sea level with sandy texture, predominance of 1:1 clay, low organic matter content, acidic soil and low natural fertility (Schmitt et al 2013). There may be an increase in Cu concentration in vineyard soils of traditional winegrowing regions of the world (Fernández-Calviño et al 2008; Toselli et al 2009; Fernández-Calviño et al 2010), including those in Brazil, as reported in some exploratory studies on copper (Casali et al 2008; Nogueirol et al 2010; Brunetto et al 2016) and zinc (Fernández-Calviño et al 2012). Frequent applications of fungicides can increase the Cu and Zn content in the soil, modifying distribution of the fractions, increasing toxicity to plants (Nagajyoti et al 2010) and transfer by the runoff solution on the soil surface and percolated in the soil profile, increasing water contamination (FernándezCalviño et al 2012)
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