NH3-Min: Reducing NH₃ Losses from Application of Synthetic Nitrogen Fertilizers and Increasing Nitrogen Use Efficiency of Fertilization

Overview

NH3-Min is a national consortium project funded through the Landwirtschaftlichen Rentenbank, coordinated by the Thünen Institute for Climate-Smart Agriculture. The project quantifies and evaluates ammonia (NH₃) losses from synthetic nitrogen fertilizers and develops evidence-based mitigation measures, while simultaneously assessing nitrogen use efficiency (NUE) in arable crop production.

Around 15% of agricultural NH₃ emissions in Germany originate from synthetic N fertilizers. The four fertilizer types investigated—urea, calcium ammonium nitrate (CAN), ammonium nitrate urea solution (UAN), and ammonium sulfate urea—together account for more than 85% of NH₃ emissions from synthetic N fertilizers applied in Germany. Winter wheat serves as the model crop across all experimental sites.

Objectives

• Quantify NH₃ emissions from different synthetic N fertilizer types and application systems across diverse German agro-climatic conditions.
• Evaluate mitigation options including incorporation/injection techniques and urease inhibitors.
• Derive site-differentiated NH₃ emission factors for synthetic N fertilizers under German production conditions.
• Assess NUE of different synthetic N fertilizers and application strategies in field crop experiments.
• Transfer knowledge to farmers, advisors, and policymakers.

Research Questions

• How large are NH₃ emissions following application of different synthetic N fertilizers?
• What are the site-differentiated NH₃ emission factors across Germany?
• How effectively can application techniques (e.g., incorporation, injection) or inhibitors (urease inhibitors) reduce NH₃ emissions?
• How do fertilizer-dependent NH₃ emissions affect yields, N uptake, and NUE in winter wheat?

Project Partners

• Thünen Institute for Climate-Smart Agriculture
• Technical University of Munich (TUM)
• Julius Kühn-Institut – Federal Research Centre for Cultivated Plants (JKI)
• KTBL – Association for Technology and Structures in Agriculture
• Christian-Albrechts-Universität Kiel
• Forschungszentrum Jülich
• Technische Universität Berlin
• Universität Hohenheim
• Bayerische Landesanstalt für Landwirtschaft (LfL)
• Ingenieurgemeinschaft für Landwirtschaft und Umwelt (IGLU)
• Landwirtschaftskammer Niedersachsen
• Stickstoffwerke Priesteritz (SKWP)

Duration: 01.2021 – 12.2024