Do DOM optical parameters improve the prediction of copper availability in vineyard soils?

International audienceAccumulation of copper (Cu) in soils due to the application of fungicides may be toxic for organisms and hence affect winegrowing sustainability. Soil parameters such as pH and dissolved organic matter (DOM) are known to affect the availability of Cu. In this study, we investigated the contribution of chromophoric and fluorescent DOM properties to the prediction of Cu availability in 18 organic vineyard soils in the Bordeaux winegrowing area (France). The DOM parameters, assessed through absorbance and fluorescence analyses, and proxies for Cu availability (total soluble Cu and free ionic Cu2+) were measured in 0.01 M KCl extracts. Total soluble Cu (CuKCl) varied 23-fold while free ionic Cu2+ varied by a factor of 4600 among the soils. DOC concentrations were similar among the soils, but the samples differed in the quality of DOM as assessed by optical spectroscopy. Multilinear regression models with and without DOM quality parameters were investigated to predict Cu availability. The best model for CuKCl successfully explained 83% of variance and included pH, CuT, and two DOM fluorescence quality indices, the FI fluorescence index, which distinguishes between microbial and higher plant origins, and the HIX humification index. For the prediction of Cu2+, pH alone explained 88% of variance and adding DOM parameters did not improve modelling. The two Cu availability proxies were related to pH. This study confirms the prominent role of pH in Cu availability and underlines the importance of DOM quality to better predict Cu solubilit

Changes over time in organic matter dynamics and copper solubility in a vineyard soil after incorporation of cover crop residues: Insights from a batch experiment

Cover crops (CCs) are increasingly used in viticulture because they benefit the soil and the environment in many ways. This study investigated the extent to which the incorporation of CC residues altered organic matter (OM) and Cu dynamics in a Cu-contaminated vineyard topsoil. A 92-day incubation period was used to monitor changes over time in carbon mineralization, carbon hydrolytic enzyme activity, concentration and optical properties of dissolved organic matter (DOM), and Cu solubility after the addition (or not) of two CC residues, oat or faba bean. The results revealed that adding CCs transitorily increased the concentration of DOM in soil solution, as well as the activity of C hydrolytic enzymes and C mineralization rates. DOM content was approximately two orders of magnitude higher in CC-amended soils than in the control soil on day 0, after which it gradually decreased to reach concentrations similar to those measured in the control soil on day 92. Analyses of DOM optical properties showed that its molecular weight and degree of humification increased over time with a decrease in its concentration. The close relationship between DOM and Cu concentrations in the soil solution suggests that degradation of CCs releases soluble forms of C capable of complexing and solubilizing Cu, and hence that incorporating CC residues can transitorily increase the solubility of Cu in vineyard topsoils. Despite their different C:N ratios, oat and faba bean had almost the same effect on Cu dynamics, implying that C inputs played a prominent role in explaining the interactions between OM and Cu within the timeframe of our experiment. In conclusion, this study enabled recommendations on how to mitigate the risk of Cu ecotoxicity associated with incorporating CCs in Cu-contaminated vineyard soils

ACcompagner et ACcélérer les TransitIONs : contributions et impacts de l’agroforesterie en Nouvelle Aquitaine

Le projet AC2TION vise à comprendre, quantifier et modéliser les effets de l’implantation d’arbres en intra etinter parcelles sur le microclimat, la fertilité et santé des sols, la biodiversité, la dispersion des pathogènes oudes pesticides ou la valeur économique des produits issus des parcelles. La synthèse de ces différents effetssefera dans une approche globale multicritère des performances environnementales, socio-économiques oumonétaires des systèmes agroforestiers en comparaison à des systèmes agricoles conventionnels. Afind’estimer la durabilité de ces systèmes, nous chercherons (1) à projeter les effets observés aujourd’hui danslaperspective d’un climat futur, en 2050 afin de proposer des adaptations à engager dès aujourd’hui etd’identifier les freins futurs et (2) à adapter les espèces ligneuses les plus adéquates à ces futures conditionspédoclimatiques. Pour l’ensemble des volets de recherche, les interactions seront fortes avec les acteurs deterrain, qui seront sollicités dans un esprit de science participative, pour contribuer à la collecte de certainesdonnées et observations de terrain. Tout au long du projet, les chercheurs et acteursseront également associéspour définir les questions de recherche et réfléchir aux conséquences des résultats obtenussur la diffusion del’agroforesterie en Nouvelle-Aquitaine

Synthèse et propriétés d'aluminosilicates non lamellaires : l'imogolite et les allophanes

Diplôme : Dr. d'Universit

Le cuivre dans les sols viticoles

National audienc

Genèse et modalités de transfert de colloïdes dans des eaux gravitaires d'un podzol alpin

National audienc

Infrastructure nationale AnaEE France

<p>Une infrastructure nationale d'Analyse et d'Expérimentation pour comprendre,  prédire et gérer le fonctionnement des écosystèmes continentaux.</p&gt