Deciphering the fate of Cu in vineyard soils: insight from the combined XAS and isotopic analyses

We propose to study the Cu speciation in a chronosequence of low-Cu acidic soils characterized by increasing vine age, which received repeated inputs of Cu-based fungicide. Copper accumulated in the surface horizons of all studied soils whereas Cu migration towards depth was only observed for the oldest vine (>72 years). Furthermore, isotopic analyses on the Cu-fungicide and the three soil profiles revealed unexpected results and a large isotopic variability. Our aim is to (1) study the temporal evolution of speciation of Cu from the fungicide after deposition on the vineyard soils and (2) investigate the drivers of Cu redistribution processes and the dominant bearing phases responsible for Cu mobility with depth in the soil profile. Due to the very low Cu concentration in soils, from 2 to 120 μg.g-1, we propose to combine XANES and EXAFS analyses to decipher the fate of Cu in vineyard soils affected by long-term Cu-fungicide application.