ReSolVe : restaurer la fertilité des sols viticoles en agriculture biologique

Le projet ReSolVe (programme Core Organic Plus) regroupe 6 pays dans l’objectif de restaurer la fertilité des sols viticoles par des méthodes alternatives dans des parcelles conduites en agriculture biologique présentant des zones caractérisées par des déficiences de vigueur, de récolte ou encore de qualité. L’objectif est de tester des techniques compatibles avec l’agriculture biologique afin de rétablir la fertilité et le fonctionnement du sol dans ces zones dégradées : ajout de compost, semis d’engrais verts, et semis d’un enherbement géré en mulch. 6 parcelles d'essai ont été mises en place en France. Les relations entre caractéristiques des sols, biodiversité (dont mésofaune), décomposition de la matière organique et conséquences sur la productivité de la vigne ont été évaluées lors d'une première année témoin en 2015 et les effets de la mise en place des modalités commencent à être évalués en 2016

Restoring soil functionality in degraded areas of organic vineyards - Preliminary results of the ReSolVe project in the French vineyards

Degraded soil areas in vineyards are associated with problems in vine health, grape production and quality. Different causes for soil degradation are possible such as poor organic matter content, lower plant nutrient availability, pH, water deficiency, soil compaction / lower oxygenation… The aim of this preliminary study is to assess soil functionality (OM decomposition), biodiversity through mesofauna diversity and consequences for vine growth and quality

Biodiversity conservation, ecosystem services and organic viticulture: A glass half-full

Organic farming is a promising but still debated option to ensure sustainable agriculture. However, whether organic farming fosters synergies or mitigates tradeoffs between biodiversity, ecosystem services and crop production has rarely been quantified. Here, we investigate relationships between multitrophic diversity (14 taxa above and belowground), yield, natural pest control and soil quality (14 proxies of ecosystem services) in organic and conventional vineyards along a landscape gradient. Organic farming enhanced biodiversity and pest control, but decreased wine production. Compared to conventional systems, multitrophic diversity was 15 % higher, and pest control services were 9 % higher in organic systems, while wine production was 11 % lower. Regardless of management type, we found a strong tradeoff between wine production and pest control, but not between wine production and biodiversity. The landscape context was not a strong moderator of organic farming effects across taxa groups and ecosystem services, but affected specific taxa and ecosystem services, especially natural pest control. Our study reveals that wine production and biodiversity conservation do not necessarily exclude each other, which implies the existence of a safe operating space where biodiversity and wine production can be combined. We conclude that organic farming can contribute to improve the sustainability of viticulture, but needs to be complemented by management options at the local and landscape scales in order to fully balance biodiversity conservation with the simultaneous provision of multiple ecosystem services.This research was funded by the research project SECBIVIT, which was funded through the 2017–2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND program, with the funding organizations: Agencia Estatal de Investigación (Ministerio de Ciencia e Innovación/Spain, grant PCI2018-092938; MCIN/AEI/10.13039/501100011033); Austrian Science Fund (FWF) (grant number I 4025-B32); Federal Ministry of Education and Research (BMBF/Germany) (grant number 031A349I); French National Research Agency (ANR); Netherlands Organization for Scientific Research (NWO); National Science Foundation (grant #1850943); and Romanian Executive Agency for Higher Education, Research, Development, and Innovation Funding (UEFISCDI). The authors also acknowledge the support of the ECOPHYTO 2+ Plan under the grant X4IN33VI (OPERA project) as well as the support the French National Research Agency (ANR) under the grant 20-PCPA-0010 (PPR Vitae, Cultivating the grapevine without pesticides: towards agroecological wine-producing socio-ecosystems). We thank Evelyne Thys and Hugo Hernandez for their help in field sampling, Lionel Delbac for the Lobesia botrana rearing, Alexis Saintilan for identifying pollinators, and Edith Gruber for identifying earthworms

The genome sequence of the grape phylloxera provides insights into the evolution, adaptation, and invasion routes of an iconic pest (vol 18, 90, 2020)

An amendment to this paper has been published and can be accessed via the original article

The genome sequence of the grape phylloxera provides insights into the evolution, adaptation, and invasion routes of an iconic pest.

BackgroundAlthough native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors such as pathogens and climate change. Limited understanding of the insect genetics resulted in successive outbreaks across the globe when rootstocks failed. Here we report the 294-Mb genome of D. vitifoliae as a basic tool to understand host plant manipulation, nutritional endosymbiosis, and enhance global viticulture.ResultsUsing a combination of genome, RNA, and population resequencing, we found grape phylloxera showed high duplication rates since its common ancestor with aphids, but similarity in most metabolic genes, despite lacking obligate nutritional symbioses and feeding from parenchyma. Similarly, no enrichment occurred in development genes in relation to viviparity. However, phylloxera evolved > 2700 unique genes that resemble putative effectors and are active during feeding. Population sequencing revealed the global invasion began from the upper Mississippi River in North America, spread to Europe and from there to the rest of the world.ConclusionsThe grape phylloxera genome reveals genetic architecture relative to the evolution of nutritional endosymbiosis, viviparity, and herbivory. The extraordinary expansion in effector genes also suggests novel adaptations to plant feeding and how insects induce complex plant phenotypes, for instance galls. Finally, our understanding of the origin of this invasive species and its genome provide genetics resources to alleviate rootstock bottlenecks restricting the advancement of viticulture