Lapie, Garraud, Gaudin, Bonnisseau, Fortin, Schetelat, Capiaux, Le Guern and Lebeau — a team spanning Nantes Université/CNRS, the French Vine and Wine Institute (IFV), the geological survey BRGM, and the animal-nutrition company ADM — report the first field assessment of copper phytoextraction from vineyard soils and the reuse of the harvested metal in animal feed (Journal of the Science of Food and Agriculture, October 2026, online ahead of print). Their motivation is regulatory: since 2018, EU rules have been cutting the copper doses permitted in viticulture, yet decades of Bordeaux-mixture fungicide use have left wine-growing soils accumulating Cu — in their three trial plots, 139–164 mg Cu kg⁻¹ — with documented harm to soil organisms.
What they found, in numbers
The work ran in two tiers. Hydroponic screening (0.32 up to 280 µmol Cu L⁻¹) across seven species — brown mustard, chicory, hemp, oats and sunflower in the main list, with ryegrass and buckwheat the exceptions to the growth-decline pattern — showed roots accumulating the most Cu in every crop, and buckwheat reaching 339.8 mg Cu kg⁻¹ in its aerial parts, the best shoot concentration of the trial. Chicory accumulated the most Cu in total.
The field tier (three vineyards in Anjou and the Saumurois, 2022 and 2023) then inverted the expected ranking. Buckwheat again concentrated the most Cu (76–96 mg kg⁻¹), but chicory — a root crop that can be fully harvested, vine rows and all — extracted the most in absolute terms: max. 98 g Cu ha⁻¹, twice as much as the other plants tested. Even so, that maximum recovered only ~10% of the Cu input from fungicides, a ceiling the authors attribute explicitly to low biomass yield.
The non-obvious implication: the root is the resource
Phytoextraction orthodoxy chases the shoot. The entire agromining model for nickel — where latex-bearing Phyllanthus rufuschaneyi reaches 25,060 µg g⁻¹ and Pycnandra acuminata 11,700 µg g⁻¹ in our database records (P. rufuschaneyi, P. acuminata) — works because a shoot hyperaccumulator lets you mow off the metal and leave the soil skeleton intact. Copper apparently offers no such shortcut among the species tested here: Cu partitions to roots, so the winning move is not a higher-shoot concentration but harvesting the entire plant, root included. That flips several practical assumptions at once: root harvest disrupts the soil far more than mowing, rules out perennial no-till cycles, and makes the biomass pipeline (uprooting, washing, processing) the engineering problem rather than the plant physiology. On the copper hub’s terms: for this metal, in these temperate cropping systems, the agronomy is the mechanism.
The sober ledger: a bleed valve, not a pump
Set the 98 g ha⁻¹ maximum against the fungicide input and the framing changes. Recovering at best a tenth of incoming Cu means phytoextraction can slow the accumulation of vineyard copper — a bleed valve on a filling reservoir — but cannot reverse it on any timeline a grower would plan around. That matters for how the result should be read in policy and extension contexts: the honest pitch is “hold the line while copper inputs fall under EU regulation,” not “clean the soil.” It also quietly explains why chicory beat buckwheat despite losing on concentration: when no tested species parks Cu in harvestable above-ground tissue, total extracted mass is decided by biomass × whole-plant concentration, and a fully harvestable root crop wins that arithmetic almost by definition.
The feed loop — and where it leaks
The second half of the paper is a circular-economy proposal: feed the Cu-enriched chicory to livestock. Based on plot results, the authors simulate Cu-enriched feed supplements with a 7% chicory inclusion limit for pigs (set by nutritional value) and 4% for cattle, covering up to 80% of Cu requirements — turning extracted metal into a saleable micronutrient product, since Cu is an essential feed additive. Note carefully: these are simulations, not feeding trials. And one loop-closure question the abstract does not address is worth flagging: if the animals eat the chicory and their manure returns to the vineyard, most of that copper comes home to the same field — “reuse” defers the export rather than completing it, unless the manure is destined for copper-poor land elsewhere. That is our inference from how Cu cycles through livestock, not a finding of the paper, but it is the first question a phytoremediation engineer should ask of any feed-the-biomass scheme.
Caveats, stated plainly
This is one region (Loire vineyards), three plots across two seasons, and the abstract names only two locations (Anjou, Saumurois) for its “three vineyards.” The feed numbers are modelled, the “twice as much” comparison is against the aggregate of the other tested crops (buckwheat still wins on concentration), and “first assessment” is the authors’ own priority claim. All figures above come from the published abstract; the full text sits behind the publisher’s access wall, so plot-level detail (root vs shoot partitioning numbers, biomass yields, soil Cu speciation) could not be checked and is not reported here.
Provenance: analysis based on the verbatim abstract of Lapie et al. (2026), J. Sci. Food Agric., DOI 10.1002/jsfa.71158 (bronze OA, publisher full text bot-blocked at retrieval time); every load-bearing number was independently re-retrieved and matched character-for-character by three separate reviewers via Crossref JATS, PubMed E-utilities, and OpenAlex + doi.org content negotiation, with zero discrepancies; nickel-hyperaccumulator contrast values from our database records; methods and limits at /methodology/.