OG RENURE: Agronomic performance of manure-derived ammonium salts as fertilisers

The RENURE Operational Group, funded by the European Rural Development Fund, advances the practical use of ammonium-based fertilizers—ammonium nitrate and ammonium sulfate—derived from manure in Flanders and the Netherlands. Field trials demonstrate comparable yields to synthetic fertilizers or manure in maize, potatoes, and winter wheat, with ammonium nitrate supporting winter wheat where manure application is insufficient. Ammonium sulfate supplies essential sulfur, though availability may constrain use in some systems. Economic viability depends on farm scale, infrastructure, and manure volume, with a 20,000-ton annual threshold for cost efficiency. Market prices range from €100 to €150 per 1,000 liters, influenced by synthetic fertilizer prices and EU regulations. Under current rules, trade requires compliance with national or mutual recognition laws. Products from manure or digestate are classified as animal manure under the Nitrates Directive, limiting nitrogen application to 170 kg/ha. RENURE IFC criteria mandate ≥90% organic carbon as nitrogen, ≤3% total nitrogen, and strict limits on copper and zinc. Storage must be appropriate: liquids in IBCs, ammonium sulfate in acid-resistant containers. Mixing during application is advised, and storage duration does not affect crystallisation.