Optimal use of recycled fertiliser in organic farming: impact on yields and nitrogen efficiency

The production and use of recycled fertiliser from biogas plants are increasing. However, a lot of questions remain unanswered concerning the fertilisers’ medium-term effects on yields, nitrogen efficiency and losses as well as on soil quality.

In this project, an exact trial over several years testing various recycled fertilisers with and without biochar is created to answer the following questions:

• Can the use of recycled fertilizer help reduce the yield gap in organic farming without affecting soil quality, product quality and the environment?
• Can the nitrogen efficiency on organic farms be sustainably improved by using recycled fertilisers, especially fermentation products?
• Can nitrogen losses be reduced by adding biochar without risking any negative effects on soil quality and the environment?

• Federal Office for Agriculture (FOAG) – Research, training and innovation

• Federal Office for Agriculture (FOAG) – Research, training and innovation

• Agroscope: Dr Jochen Mayer, Division Agroecology and Environment, Reckenholzstrasse, 8046 Zurich

• Bünemann-König Else (Department of Soil Sciences)

• Efosa Norah (Department of Soil Sciences)
• Krauss Maike (Department of Soil Sciences)
• Kuhn Anton (Department of Soil Sciences)
• Mäder Paul (Departement für Bodenwissenschaften)
• Munyangabe Adolphe (Department of Soil Sciences)
• Perrochet Frédéric (Department of Soil Sciences)
• Sauter Moritz (Department of Soil Sciences)

Project leader

• Nutrient Management & Symbiosis (Department of Soil Sciences, FiBL Switzerland)
• Soil fertility & Climate (Department of Soil Sciences, FiBL Switzerland)