Friday, February 01, 2008

Is it really organic?

It can be difficult to determine whether something is really organic. How can you tell if a producer is calling food organic that isn't? While most persticides are likely to leave residues that could be tested for, fertilisers are more difficult to detect. One possibility is to look for differences in the ratios of stable isotopes of nitrogen - nitrogen. Spanish scientists Francisco del Amora, Joaquín Navarroa and Pedro Aparicio decided to see if they could tell the difference between organic and conventionally grown crops on the basis of nitrogen isotope ratios. They concluded that it was possible to detect fertiliser use.
Agencies for organic farming certification require techniques to verify the organic nature of the N fertilizers applied to crops. Results show that significant differences have been found between organic and not fully organic practices. Thus, this study demonstrates that with N-isotopic techniques it is possible to discriminate the use of chemical fertilizers in the organic production of sweet peppers with respect to strictly nonorganic crops. Further studies including the effects of different soils characteristics, climate, and biotic or abiotic stress could be useful in determining the proper interval of 15N/14N ratio to exclude nonorganic fertilization practices.
del Amora,F.M., Navarroa J., and Aparicio, P.M. 2008. Isotopic Discrimination as a Tool for Organic Farming Certification in Sweet Pepper.

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