Heavy Metal-Based Fungicides Alter the Chemical Fractions of Cu, Zn, and Mn in Vineyards in Southern Brazil

This study aimed to evaluate Cu, Zn, and Mn fractions in vineyard soils in two important wine-growing regions in Latin America, which have soils with different soil organic matter (SOM) and clay contents. Soils were collected from vineyards aged 35, 37, and 39 years (Serra Gaúcha) and 13, 19, and 36 years (Campanha Gaúcha). In each region, soils were collected from a non-anthropized area, and in the oldest vineyards, the collection was conducted on and between the planting lines. The available and total Cu, Zn, and Mn contents were analyzed in addition to the chemical fractions. The ΔCu, ΔZn, and ΔMn were also calculated by subtracting the contents of each fraction of the vineyards from the reference areas. The use of fungicides promotes increased metal contents in vineyard soils. In soils with high SOM contents, Cu tended to increase in the organic fraction in surface and depth. In contrast, Zn increased in the residual fraction, and Mn increased in most bioavailable fractions. Cu and Zn increased their contents in soils with low SOM and clay contents in the organic and mineral fractions. Mn accumulated in the mineral and residual fractions.