Copper Content and Export in European Vineyard Soils Influenced by Climate and Soil Properties.

Copper-based fungicides (Cu) are used in European (EU) vineyards to prevent fungal diseases. Soil physicochemical properties locally govern the variation of the total copper content (Cu) in EU vineyards. However, variables controlling Cu distribution at a larger scale are poorly known. Here, machine learning techniques were used to identify governing variables and to predict the Cu distribution in EU vineyards. Precipitation, aridity and soil organic carbon are key variables explaining together 45% of Cu distribution across EU vineyards. This underlines the effect of both climate and soil properties on Cu distribution. The average net export of Cu at the EU scale is 0.29 kg Cu ha, which is 2 orders of magnitude less than the net accumulation of Cu (24.8 kg Cu ha). Four scenarios of Cu application were compared. The current EU regulation with a maximum of 4 kg Cu ha year may increase by 2% of the EU vineyard area, exceeding the predicted no-effect concentration (PNEC) in soil in the next 100 years. Overall, our results highlight the vineyard areas requiring specific remediation measures and strategies of Cu use to manage a trade-off between pest control and soil and water contamination.