Overcoming yield gaps in organic and biodynamic viticulture: insights from an 18-year field trial

Abstract Addressing environmental degradation and fostering agricultural sustainability are critical challenges of the twenty-first century. Agroecological practices such as organic and biodynamic farming are vital for transforming agriculture and enhancing ecosystem services by avoiding synthetic inputs. While often criticized for lower yields, little is known about how these systems adapt and perform over extended periods under varying climatic conditions, particularly for perennial crops such as grapevines. This represents a major knowledge gap, as understanding their long-term adaptive capacity is essential for designing resilient and sustainable production systems under climate change. This 18-year field trial in Geisenheim, Germany, addresses this gap by assessing the long-term effects of organic, biodynamic, and integrated management on Vitis vinifera cv. Riesling. It represents the only long-term study on perennial crops to systematically compare these systems’ impact on agronomic parameters, plant performance, and grape quality, observing their evolution post-conversion and response to climatic variability. Initially, organic (−17%) and biodynamic (−14%) systems showed lower yields and reduced vine vigor compared to integrated management. However, yield gaps narrowed significantly after approximately a decade. Change point analysis revealed improved relative yields in organic and biodynamic plots 8–9 years after conversion, accompanied by stable or improved Ravaz index values. Notably, in hot, dry vintages, organic and biodynamic systems exhibited enhanced yield effect sizes (+2.3% and +9.0%, respectively) and increased yeast-available nitrogen. Conversely, yield gaps persisted in cooler, wetter vintages, likely due to pathogen-induced losses. Nutrient deficiencies were not the primary cause of initial yield reductions, and grape quality parameters showed minimal treatment differences. These long-term findings demonstrate that organic and biodynamic viticulture can overcome initial yield deficits and potentially outperform integrated management under increasingly warm, dry conditions. The results highlight the adaptive capacity and climate resilience of agroecological systems, offering a sustainable path for future perennial agriculture.