A meta-analysis of the ecotoxicological impact of viticultural practices on soil biodiversity

Viticulture is a key sector of the agricultural economy of the main wine-producing countries, e.g. Italy, France, Spain and the USA, but is also one of the main users of phytosanitary products and mechanization. Over the last 15 years, numerous studies of the effect of viticultural practices on soil quality have evidenced strong impacts on soil physical, chemical and biological quality. However, to date a global analysis providing a comprehensive overview of the ecotoxicological impacts of viticultural practices on soil biological quality is missing. Here, we conducted a meta-analysis of the literature in order to rank viticultural production systems and practices according to their impact on soil biodiversity and functioning in the context of the agro-ecological transition. We screened about one hundred articles and gathered data on more than 50 viticultural factors and 230 soil biological parameters. The results show that soil microorganisms are threefold to fourfold higher under organic viticulture than under conventional viticulture in terms of biomass, respiration and activity; and that biodynamic viticulture shows a similar trend than organic viticulture. Tillage, the absence of soil cover and mineral fertilization are significantly deleterious to the whole soil biodiversity, whereas cover crops, organic fertilizers and addition of grapevine pruning wood are beneficial. Pesticides-especially herbicides-have an ecotoxicological impact on soil organisms, notably on nematodes with losses of up to two-thirds of individuals. The pivotal role of biodiversity in soil functions implies that this degradation will have substantial consequences on the ecological and agronomical services provided by the soil for vine production. On this basis, we propose a potentially more agro-ecological and sustainable vine production system based on the more virtuous practices.