Yields, Yields, Yields: Organic and Biodynamic Viticulture Increases Resilience and Yields in Hot, Dry Years Compared to Conventional Systems, German Researchers Find

German researchers comparing conventional, organic and biodynamic Riesling vineyards at a Geisenheim University research site announced at a January conference in Avignon that in their comparative study of conventional, organic and biodynamic vines, yields in organic and biodynamic vineyards are higher than conventional in hot and dry years. 

The biological approaches also resulted in higher fruit quality, their study said. 

LOWER YIELDS INITIALLY BUT HIGHER IN HOT AND DRY YEARS

Though the researchers found that yields from organic and biodynamic vineyards typically decrease 14 to 17 percent initially, the organic and biodynamic vines outperform conventional vines in hot and dry vintages. 

"When you have a close look at the data, it's actually interesting to see that there's a lot of years, especially in the beginning of the trial, where the independent [conventional] treatment shows the highest yields," said Doring. "But in 2018, that started to change."

"You might remember that 2018 was the first, horribly hot and dry year here in Germany, followed by 2019 and 2021, which were hot and even drier."

"We didn't observe any yield reduction [in the organic and biodynamic blocks].  

BIODYNAMIC VINES HIGHEST PERFORMING IN HOT, DRY YEARS

The results were even more dramatic in 2022. "It was a hot and dry year–the hottest recorded in Geisenheim so far, and actually the biodynamic treatment was overperforming," she said. "So that was remarkable." 

The team's 2019 paper "Conversion to organic and biodynamic viticultural practices: impact on soil, grapevine development and grape quality" found a number of advantageous attributes of organic and biodynamic vines. 

 "Compared with plots under integrated [conventional] management, plots under the two biological treatments were characterized by higher soil quality and lower vegetative growth and grape yield, and therefore higher exposure of grapes and lower grape cluster compactness, and, probably as a result of these morphological differences, lower incidence of acetic acid rot...

"...analysis clearly differentiated the three treatments, and showed that biodynamic management had more pronounced effects than organic management in terms of enhanced soil fertility and reduction of vegetative growth."

Quality was definitely a factor, Doring said. "Organic and biodynamic treatments have a significant significantly higher amount total flavanols."

CONCLUSION

The 2019 paper stated, "Conclusions: In the present study, organic and especially biodynamic management resulted in a morphology favouring production of high-quality grapes." 

The team is preparing to publish its latest findings, including the yield graph featured here, Doring said.