MADISON, WI, January 28, 2008 -- As organic farming becomes more common, methods to identify fraud in the industry are increasingly important. In a recent study in Journal of Environmental Quality, scientists successfully use nitrogen isotopic discrimination to determine if non-organic, synthetic fertilizers were used on sweet pepper plants.
Scientists at the Instituto Murciano de Investigacin y Desarrollo Agrario y Agrario y Alimentario (IMIDA) jointly with the Instituto de Agrobiotecnologa (UPNA-CSIC), in Spain, investigated the use of isotopic discrimination in organic crops to detect if chemical N fertilizers were added, in a study funded by the Fundacin Sneca de la Regin de Murcia. Specifically, they measured 15N-abundance variations in sweet pepper plants with three common manures, with or without the addition of chemical fertilizers during the crop cycle.
Results from the study were published in the January-February issue of the Journal of Environmental Quality. The research was also presented in Naples, Italy, at the GreenSys2007 Symposium of the International Society for Horticultural Science in October 2007.
Francisco del Amor, who conducted the study, said that isotopic discrimination has demonstrated that we can successfully identify fraud if synthetic N fertilizers are used in the organic production of sweet peppers; however, further studies including the effects of different soil characteristics, climate, and biotic or abiotic stress could be useful in determining the proper interval of 15N-values to exclude non-organic fertilization practices for certification policies.
15N abundance in the atmosphere, the largest N reserve in the world, remains constant around the planet. However, several physical, chemical, and biological processes and reactions implicated in the synthesis and transformation of organic compounds present different affinities for 15N or 14N isotopes. Due to this discrimination, products
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American Society of Agronomy