Copper contamination in agricultural soils: A review of the effects of climate, soil properties, and prolonged copper pesticide application in vineyards and orchards

Copper contamination stemming from copper-based pesticides poses a grave concern in vineyards and orchards, causing toxicity to soil organisms. Here, we present a comprehensive review of global data encompassing copper levels in these soils, coupled with variables such as the age of agricultural establishments, climate, soil organic matter content, soil pH, and farming practices (organic vs. conventional). The results suggest that there are three pivotal determinants driving copper content in vineyard and orchard soils: climate, the age of agricultural establishments, and soil organic matter content. It was impossible to estimate soil pH’s effect on soil copper content because of its dependence on precipitation. Copper content in vineyard and orchard soils worldwide follows a direct correlation with precipitation while inversely correlating with aridity (i.e. potential evapotranspiration divided by precipitation). Furthermore, a clear linkage emerges between farm age and increased copper content in soils globally. Intriguingly, the increased soil organic matter content has shown inverse impacts on soil copper levels. These effects of soil properties on soil copper contents were discussed in terms of copper losses from soil via surface runoff. However, no discernible disparities in soil copper content between organic and conventional farming systems were found. This worldwide survey not only underscores the established influence of climate on European vineyards but also sheds novel light on the historical legacy of copper contamination in these landscapes.