Field trial

Biogas digestate is increasingly used in organic farming to improve soil fertility and crop yields, but it can also cause environmentally relevant N₂O emissions. A four-year field study in southern Germany (2019–2022) tested how digestate affects winter wheat yield, nitrogen efficiency, and N₂O-N emissions. Digestate application strongly increased yields, though long-term fertilized plots performed better than newly treated ones. The highest N₂O emissions occurred in long-term fertilized plots, but surprisingly high emissions also appeared in winter in unfertilized plots. Overall, the study shows that N₂O emissions are influenced not only by fertilization but also by tillage, post-harvest practices, previous crops, and weather conditions.

This study evaluated the performance of animal-based digestates (from pig, chicken, and cow manure) as sustainable fertilizer alternatives to synthetic nitrogen over three consecutive years. Digestate applications enhanced soil phosphorus and potassium levels and led to higher grain yields, particularly in the third year. Nitrogen use efficiency remained moderate but showed a strong positive relationship with yield. Although grain and straw quality responses varied, no adverse effects were observed. Overall, the findings highlight the promising short- to mid-term potential of digestates under favorable climatic conditions.