Spontaneous cover crop characterization is relevant to define a sustainable soil management strategy in vineyard

Summary

Spontaneous cover cropping is a common practice in Mediterranean vineyards because it is often seen as less competitive and easier to manage than sown covercrops. However, the services provided by the spontaneous flora highly depend on the species, these latter being influenced by the soil management practices. This study analyzes the specific and functional composition of the vineyard flora as influenced by three soil management strategies. To do so, weed cover was sampled at 5 dates during two years after the settlement of the experiment in a vineyard in the South of France. The three soil management treatments were: a control treatment (C) corresponding to a spontaneous cover regularly mowed, a spontaneous cover with organic amendment application each year (OF) and a green manure (Vicia faba) sown in autumn and incorporated at budburst (GM). 122 different species corresponding to 27 families, were identified (25 to 41 different species per treatment at a date), with only five species in more than 50% of the quadrats, while a majority of species, 85 out of 122 were present in less than 10%. The functional approach allows characterizing spontaneous vegetation according to species trait values and the ecosystem services they may provide: for example, the species being uncompetitive for vineyards while improving soil fertility are Crepis foetida and Lactuca serriola. On the contrary, species such as Geranium rotundifolium are more competitive and less interesting for soil fertility. This study contributes to a first identification of the soil management practices that can drive the trajectories of the spontaneous flora towards the best composition, hereby contributing to design more sustainable grapevine systems.