This Summary highlights the results of the full outcome of this project, which is available in the report found in the outcome PDF below.
This study presents an approach and methodology for detecting probable adulteration of organic fertilizers and other amendments by synthetic fertilizer and other chemical nutrient sources. The low cost and relative simplicity of the protocol will ensure that regulators and test laboratories can routinely and efficiently test commercially available organic fertilizers. The findings present a set of common methodologies that include analysis for ammonia and total carbon and nitrogen that are readily available to soil test labs and the California Department of Food and Agriculture (CDFA) Inspection Services Center for Analytical Chemistry.
These minimum analyses are likely to flag greater than 90% of samples adulterated with synthetic sources of nitrogen. Any individual suspecting a fertilizer to be adulterated could submit a sample of fertilizer to a commercial soil test lab or the CDFA to determine with high probability whether the fertilizer is authentic. Additional stable nitrogen isotope and spectroscopic analysis can refine the identification of adulterated fertilizer samples. Since these analyses are not routine for soil test labs, the California Department of Food and Agriculture Inspection Services Center for Analytical Chemistry may consider accepting these suspected samples for further analysis. Legitimate producers of fertilizers will benefit by having a defined set of testing protocols to ensure the quality of their products and manufacturers of adulterated organic fertilizers and amendments will face the appropriate scrutiny to ensure the authenticity of their products.