Organic and Biodynamic Viticulture Affect Biodiversity and Properties of Vine and Wine: A Systematic Quantitative Review

Demand for organically grown crops has increased exponentially in the last few decades. Particularly in the wine sector, organic and biodynamic management systems are gaining more and more importance, with some of the most prestigious wineries converting to organic or biodynamic viticulture. The purpose of this study was to review evidence comparing effects of conventional, organic, and biodynamic viticulture on soil properties, biodiversity, vine growth and yield, disease incidence, grape composition, sensory characteristics, and wine quality. Only studies with representative field replicates or studies with a representative number of samples were included. Soil nutrient cycling was enhanced under organic viticulture, especially after conversion was completed. Cover crop mixtures used, compost application, and the absence of herbicides might be factors that account for higher biological activity in organically and biodynamically managed soils. Seventeen out of 24 studies observed a clear increase in biodiversity under organic viticulture on different trophic levels. Plant protection regime and cover crop mixtures mainly determine higher biodiversity in organic and biodynamic viticulture. Organic and biodynamic treatments showed 21% lower growth and 18% lower yield compared to conventional viticulture. The decrease of growth and yield under organic and biodynamic viticulture was not correlated to the growth or yield level under conventional viticulture. A decrease in soil moisture content and physiological performance (assimilation rate, transpiration rate, and stomatal conductance) under organic and biodynamic viticulture is likely to be responsible for the lower growth and yield in the respective management systems. Juice total soluble solids concentration did not differ among the different management systems. No overall differences in berry composition or juice and wine quality among management systems could be observed. By describing different hypotheses concerning the effects of organic and biodynamic viticulture, this review and meta-analysis provides helpful guidance for defining further research in organic agriculture on perennial, but also on annual, crops.