## 1 Introduction  
Among the processed crops, which include all agricultural and food products obtained from their respective primary raw materials, wine is the second most important in Europe after beer (FAOSTAT [1]). The European wine-growing areas are generally located in climatic zones which, however, favor the occurrence of fungal diseases, including downy mildew (_Plasmopara viticola_). The regular and intensive use of Cu-based fungicides (e.g., Bordeaux mixture, Cu oxychloride, or Cu hydroxide) to protect grape vine plants from these pests has led, in the long-term, to an accumulation of Cu in vineyard soils (especially in the upper horizons), hence reaching concentrations far above the trace levels required for healthy plant growth [2] and possibly even exceeding the limits prescribed for safe agricultural soils (50-150 mg kg\({}^{-1}\), with lower levels for acid soils) in the European Union (EU). In 2018, the results of the study, which used 21,682 soil samples to study copper distribution in 25 EU Member States [3], showed that vineyards have the highest average soil Cu concentration of all land use categories. As organic agricultural methods are becoming more common, especially in Europe, where over the decade 2010-2019 the total area of vineyards under organic management tripled to 380,000 ha [4], the total use of Cu-based fungicides remains an important issue, since these pesticides have not yet an effective substitute in organic viticulture. It must be stressed that Cu is also an essential element for plants and is, by definition, necessary for the proper functioning of all organisms, since it plays a key role in various biochemical and physiological processes associated with the growth and development of plants [5]. Nevertheless, depending on the concentration and its bioavailable fraction, Cu can also have toxic effects on plants, especially at very high bioavailable Cu concentrations; grape vine plant growth and productivity could be severely impaired [6; 7; 8; 9]. Winegrowing is considered a low contributor to greenhouse gases (GHG) emissions compared to other human activities, but more attention should be paid to the consequences that climate change will have on vineyards in the future [10]. Taking into consideration different prediction models, we can see that for Mediterranean regions in the twenty-first century, the mean temperature will warm 20% more than the global average [11]. Warming will be particularly large in summer and for the northern Mediterranean land areas, where Slovenia is also located, and the increase is predicted to be up to 100% larger than the global average temperature rise [11]. Reduction of precipitation (predicted decrease average rate around \(-\)20 mm/\({}^{\circ}\)C) will affect all seasons; moreover, for the northern Mediterranean region, the reduction will be largest in summer [11], when the vine plants need the majority of water as the grapes develop and ripen during this time. Based on these predictions, severe or extreme droughts are expected to become substantially more frequent than the recent past [12]. If extreme droughts in the recent past were occurring once in 10 years, in southern Europe by the late 21 st century with increase of temperature for 8.5 \({}^{\circ}\)C, such events would be experienced about every second year [13], regardless of the degree of mitigation of CO\({}_{2}\) emissions that will be followed [14]. This alternative stability of climatic pressure lies outside the limits of ecosystem resilience and may indicate that in some cases vegetation will either adapt to the new conditions or be succeeded by more water-stress-tolerant species [15]. Climate changes raise concerns about the fate of the Mediterranean wine production and the effectiveness of mitigation measures. The availability and leaching of Cu is strongly correlated with soil pH and soil organic matter content [16], type and content of clay [17], and carbonate and phosphate content [18].