Effects of biodynamic preparations 500 and 501 on vine and berry physiology, pedology and the soil microbiome

In the pursuit of increasing sustainability, climate change resiliency and independence of synthetic pesticides in agriculture, the interest of consumers and producers in organic and biodynamic farming has been steadily increasing in recent decennia. This is, in particular, the case for the vitivinicultural industry in Europe, where more and more producers are converting from organic to biodynamic farming. However, clear scientific evidence showing that biodynamic farming improves vine physiology, vine stress resilience, soil quality related parameters and berry or wine quality is still lacking, despite the growing number of research studies on this issue. To investigate whether biodynamic farming methods have an impact on vine physiology, berry quality and the environment, a five-year experiment was set up in 2016 in a commercial vineyard in Switzerland. In this trial, the two main biodynamic preparations 500 and 501 were applied and compared to an organic control. Vine and berry physiology (net photosynthesis, vigour, sugar, organic acids, berry weight, yield) were assessed from 2016 to 2020. Soil physical properties (soil bulk density, water holding capacity, soil structural stability, macropore volume) were analysed from 2017-2020, and, soil fungal communities were analysed by DNA-sequencing in the last year of the experiment (2020). None of the parameters related to vine and berry physiology showed significant differences throughout the duration of the experiments, except photosynthesis, which was higher when biodynamic preparations were applied at one time point. Similarly, the soil’s physical properties were not influenced by the application of the two biodynamic preparations in all years. Regarding the soil microbiome, the preparations 500 and 501 neither led to significant differences in fungal diversity nor seemed to impact the soil fungal communities. The present study confirms previous findings of different research teams that did not observe significant differences between organic and biodynamic farming methods in terms of observed soil and vine parameters.