Chemical characterization of commercial organic fertilizers

• Published in: Archiv für Acker- und Pflanzenbau und Bodenkunde Vol. 61; no. 7; pp. 989 - 1012
• Main Authors: Moller, Kurt, Schultheis, Ute
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 03.07.2015; Taylor & Francis Ltd
• Subjects: Animal manures; antibiotic residues; carbon; commercial organic fertilizers; composts; Environmental risk; farmers; Fertilizers; Germany; Heavy metals; Livestock; metalloids; Micronutrients; nitrogen; Nutrient concentrations; nutrient content; nutrients; Organic farming; Organic fertilizers; Organic matter; Persistent organic pollutants; Pesticide residues; Pesticide toxicity; Pesticides; pollutants; risk; Soil sciences; toxic substances; toxicity; Germany
• ISSN: 0365-0340; 1476-3567; 1476-3567
• DOI: 10.1080/03650340.2014.978763

A wide range of commercial organic fertilizers is currently available to organic farmers. Their use has numerous agronomic implications, including the supply of plant macro- and micronutrients, organic matter, but also pollutants such as toxic elements (metals (often referred to heavy metals), metalloids, and non-metals), persistent organic pollutants, pesticides, and antibiotic residues. For many organic fertilizers, the database concerning all these characteristics is weak. Therefore, in the frame of collections carried out throughout Germany, 77 samples of commercial organic fertilizers were analyzed for their nutrient and pollutant contents. Commercial organic fertilizers differ widely in nutrient concentration as well as in nutrient spectrum, meaning large differences among the fertilizers in their suitability to complement the nutrient supply by base organic fertilizers like composts, livestock manures, or digestates. The sampled commercial organic fertilizers show stable values for few characteristics (e.g. concentration of organic matter, carbon, and nitrogen), and high variation in the composition of the most other macro- and micronutrients as well as toxic metals. Consequently, the use of default values in budget calculation sheets can result in considerable errors of estimation. The concentrations of toxic elements, pesticides, and persistent organic pollutants are low, indicating the low risk of pollution related to their use.