TY - JOUR AU - Mukome, Fungai N.D. AU - Doane, Timothy A. AU - Silva, Lucas C.R. AU - Parikh, Sanjai J. AU - Horwath, William R. TI - Testing protocol ensures the authenticity of organic fertilizers JF - California Agriculture JO - Calif Agr Y1 - 2013/10/01 VL - 67 IS - 4 SP - 210 EP - 216 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://dx.doi.org/10.3733/ca.v067n04p210 L3 - 10.3733/ca.v067n04p210 AB - There is a pressing need for methodology to confirm the authenticity of fertilizers labeled “suitable for organic production.” In this study, we developed a testing protocol that can be used by laboratories and regulatory agencies to detect adulteration of organic fertilizers and soil amendments with a synthetic nitrogen source. By conducting an extensive literature review and analysis of 180 commercially available raw materials, organic fertilizers, soil amendments and synthetic fertilizers, we compiled a comprehensive database of quantifiable properties of those materials. We analyzed their ammonium content, C:N ratio and stable nitrogen isotope ratio, and for each metric we set thresholds that flag products with a high probability of adulteration. The protocol can be used to authenticate organic fertilizer products and bring transparency to the industry.