Permanent cover crop as a strategy to promote soil health and vineyard performance

Conventional viticulture involves a high use of inputs that negatively impact ecosystem services and biodiversity. Traditionally, vineyards are rainfed systems and vegetation is removed or sprayed with herbicides to avoid excessive competition for water and nutrients. Introducing cover crops can positively promote several ecosystem services and particularly soil and crop health and biodiversity. To assess the impact of under-trellis soil management (permanent cover crop-PCC vs herbicide weeding-HW) in an irrigated vineyard of Tannat/SO4, grapevine rhizosphere microbiota, soil health and plant performance were studied along 2019/2020 season. Rhizosphere microbiota (prokaryotic and fungal) diversity and composition at three different phenological stages (flowering, veraison, harvest) was determined by culture dependent and independent methods and soil physical, chemical, and biological properties and plant performance was explored. Rhizosphere microbiota differed between managements and phenological stages. Several taxa respond to PCC, among them were Pseudomonas, Pantoea, Butiaxella, Enterobacter, Trichoderma and Penicillium. PCC compared to HW improved bulk soil density, soil respiration rate, soil protein index and potentially oxidizable carbon, and showed greater proportion of medium aggregates, as well as increased levels of pH, soil organic carbon and nitrogen. Also, less incidence of Botrytis cinerea latent infections was observed under PCC. Vine yield, grape must composition and nutritional status were not affected. In this context, PCC appears as a sustainable agricultural practice for vineyards to promote biodiversity, and soil and plant health. More studies are needed to assess how cover crops promote beneficial microbes, particularly those involved in plant growth and defense responses.