Impact of organic inputs on soil biodiversity in vineyard systems. A monitoring approach during 20 years

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.

Un programme de recherche concernant les facteurs naturels et humains des terroirs viticoles a été développé dans le vignoble A.O.C. de l’Anjou, sur une surface d’environ 30.000 Ha

Downy mildew, caused by the oomycete Plasmopara viticola (Berk. & M.A. Curtis) Berl. & De Toni, is one of the most destructive grapevine diseases mostly affecting Vitis vinifera L. and impacting on viticulture. The pathogen invasion can induce in grapevine multiple defense reactions, first PAMP-Triggered Immunity and secondly Effector-Triggered Immunity. Plasmopara viticola can overcome these defense mechanisms through the secretion of effectors, such as RxLR, into the plant cells, making it easier for the oomycete to infect grapevines. Currently, the use of chemical pesticides remains the most effective way to control the pathogen with severe negative side effects on the environment and animal health.

Reducing sugar accumulation in grape (Vitis vinifera L.) berries may be a way to mitigate the effect of climate change. Managing canopy and crop load is an effective way to do so, however, reducing canopy size has been demonstrated to induce undesirable effects on anthocyanins. The aim of this study was to test if an application of exogenous ABA on the grape berries of defoliated vines (⅔ of the leaves removed) can result in slower sugar accumulation while maintaining grape and wine quality. An experiment with defoliation and exogenous ABA application on directly on clusters (factorial design 2×2) was performed with ‘Tempranillo’ fruit-bearing cuttings.

The goal of this work was to determine the spatial variability of terroir using the isotope composition of wine. Carbon (δ13C) and oxygen (δ18O) stable isotope composition was measured in wines from Tempranillo (Vitis vinifera L.) vineyard, located in Rioja Appellation (Spain). Stable isotope composition, leaf area, vigour, yield components, grape and wine composition were determined in a grid of 85 geo-referenced points, that was drawn across the 5 ha vineyard area