Whole‐crop harvestable chicory for the phytoextraction of copper from wine‐growing soils and its use in animal feed

Abstract

Abstract Background Since 2018, European Union regulations have reduced copper (Cu) doses in viticulture to combat fungal diseases, but Cu continues to accumulate in soils, potentially harming soil organisms. The aim of our study was to reduce the Cu content of soils by means of phytoextraction, followed by the reuse of Cu for animal feed supplements. Results Firstly, hydroponic crops (brown mustard, chicory, hemp, oats and sunflower) showed that plant growth decreased with increasing Cu exposure (0.32 up to 280 μmol L −1 ), except for ryegrass and buckwheat. The roots accumulated the most Cu, and buckwheat reached 339.8 mg Cu kg −1 in the aerial parts. Chicory, which can be fully harvested, accumulated the most Cu. Then, all plants (except hemp and sunflower which cannot be grown between the rows of vines) were tested on plots (139–164 mg Cu kg −1 ) in three French vineyards (Anjou, Saumurois) in 2022 and 2023. Buckwheat concentrated the most Cu (76–96 mg kg −1 ), but chicory extracted the most Cu (max. 98 g ha −1 ), though it could only extract a maximum of 10% of the Cu input from fungicides. The low biomass yield explains this. In the absence of plants accumulating Cu mainly in their aerial parts, our study demonstrates that whole‐crop harvestable plants such as chicory (root plant) are more efficient. Compared to the other plants tested, chicory extracted twice as much Cu. Finally, Cu‐enriched plant‐based food supplements were simulated. Based on the results obtained for the vineyard plots, chicory's incorporation depends on its nutritional value, with an acceptance limit of 7% for pigs. For cattle, chicory can be included at 4%, covering up to 80% of Cu requirements. Conclusion Our results demonstrate the first assessment of phytoextraction of Cu from vineyard soils and its reuse in animal feed and the advantage of using a whole‐crop harvestable plant. © 2026 Society of Chemical Industry.