Agronomic Performance of Novel Biobased Fertilizers Across European Field Trial Sites

Substituting mineral fertilizers with novel biobased fertilizers (BBFs) produced from various organic waste and side streams could contribute to a reduction in the environmental and climate impacts of fertilizer production and use and the recycling of otherwise potentially wasted nutrients. For the substitution to be beneficial for farmers, the environment, and food security, the BBFs need to be effective and reliable. However, the agronomic performance of novel BBFs has not yet been well studied. The current study investigated the agronomic performance of seven commercial BBFs at five field sites across Europe covering different climates, soil types and crop rotations. Additionally, two or three local BBFs were tested at each site. The BBFs had agronomic performances with an average nitrogen fertilizer replacement value of 71% across sites and years. Variations in the agronomic performance of the BBFs were observed between the trial sites and years, but in general, no significant differences in yields were found compared with the mineral N fertilizer reference applied at the same total N level. The BBFs tended to have a higher mineral N fertiliser replacement value when incorporated compared to surface application. Of the 18 BBFs tested, 8 had a mineral fertilizer replacement value above 75%, 6 were in the range 60-75% and 4 were in the low range of 10-60%. The residual effect of BBFs in the year after application was not significantly higher for any of the BBFs than that of the mineral N fertilizer.