No yield advantage of biodynamic compost preparations in a long-term field trial

Abstract

Abstract Biodynamic farming is a growing branch of organic farming which uses various so-called biodynamic preparations with the aim to enhance plant growth and soil quality. These preparations comprise plant parts fermented in animal sheaths (e.g., cow intestines or deer bladders) which are then applied to manures and composts before applying to the field (compost preparations). Two special preparations based on manure and silica are applied to the crops as field sprays (spray preparations). The effect of these biodynamic preparations, however, is a matter of debate. In a long-term experiment over 27 yrs, within an organic crop rotation, the use of biodynamic compost preparations has recently been shown to impact the soil biological community. Using the same experiment, we investigated whether these soil-level effects also displayed in agronomic parameters of arable crops. We found that the use of biodynamic compost preparations, when compared with farmyard manure (FYM) compost application without preparations, had no effect on yield in any of the investigated crops (spring wheat, winter wheat, oats, winter rye, faba bean, potatoes, maize, and grass/clover), or when data from all crops were pooled. Temporal yield stability of spring wheat and grass/clover was also unaffected by the biodynamic compost preparations. The application of FYM compost, however, led to significant increases in both yield and yield stability as compared to the non-fertilized control. We conclude that while biodynamic compost preparations did influence biological processes in the soil, they did not increase the crop yields in our long-term trial.