Soil microbiota respond to green manure in organic vineyards.

AIMS: The aim of this work was to investigate the effects of biodynamic management with and without the addition of green manure, in comparison with organic management, on the microbiota in vineyards soil. METHODS AND RESULTS: High throughput sequencing was used to compare the taxonomic structure of the soil bacterial and fungal communities from vineyards managed with different methods (organic, biodynamic or biodynamic with green manure). Our results showed that microbial communities associated with biodynamic and organic farming systems were very similar, while green manure was the greatest source of soil microbial biodiversity and significantly changed microbial richness and community composition compared with other soils. Green manure also significantly enriched bacterial taxa involved in the soil nitrogen cycle (e.g. Microvirga sp., Pontibacter sp. and Nitrospira sp.). CONCLUSIONS: Our results showed that the diversity and composition of the microbial communities associated with biodynamic and organic farming systems were similar, indicating that the use of biodynamic preparations 500 and 501 did not cause any significant detectable changes to the soil microbial community in the short term, while the effects of green manure were significant in soil microbiota. SIGNIFICANCE AND IMPACT OF THE STUDY: The microbiological richness and structure of soil are used as a sensitive indicator of soil quality. The extension of organic/biodynamic farming, associated with green manure application, could contribute to increase the abundance of functional groups of biological and agronomical relevance and maintaining microbial biodiversity in vineyard soils.

Evaluation of the oenological suitability of grapes grown using biodynamic agriculture: the case of a bad vintage.

AIMS: We compare the evolution of the microbiota of grapes grown following conventional or biodynamic protocols during the final stage of ripening and wine fermentation in a year characterized by adverse climatic conditions. METHODS AND RESULTS: The observations were made in a vineyard subdivided into two parts, cultivated using a biodynamic and traditional approach in a year which saw a combination of adverse events in terms of weather, creating the conditions for extensive proliferation of vine pests. The biodynamic approach was severely tested, as agrochemicals were not used and vine pests were counteracted with moderate use of copper, sulphur and plant extracts and with intensive use of agronomical practices aimed at improving the health of the vines. Agronomic, microbiological and chemical testing showed that the response of the vineyard cultivated using a biodynamic approach was comparable or better to that of vines cultivated using the conventional method. CONCLUSIONS: The work suggests that biodynamic cultivation of the grapevine may be sustainable even in difficult conditions, representing an interesting alternative to traditional vine-growing approaches. SIGNIFICANCE AND IMPACT OF THE STUDY: This theme is topical and of interest to winemakers and consumers today, but is not easy to study due to the difficulties in finding vineyards with homogeneous characteristics, cultivated using different agronomical protocols. The particular climatic conditions observed in 2014 made this year a rare model, making it possible to verify the applicability of biodynamics to vine growing. The strict experimental plan gave results particularly useful for understanding the features of grape microbiota in a biodynamic context.