Journal of Taiwan Agricultural Research

Author:Tsang-Sen Liu, Tsung-Ren Peng*, Sheng-Hong Wu, Chia-Hua Fan, and Yu-Wen Lin

Abstract:

    This study was to evaluate whether the isotopic technique can be used as one of the certified methods that discern organic vegetables by analyzing the nitrogen isotope composition (δ¹⁵N) of Pak-choi (Brassica chinensis L.) and the fertilizer applied.  Four fertilization treatments including control (CK), organic fertilizer (OF), chemical fertilizer (CF), and combined use of organic and chemical fertilizers (OC) were performed.  The isotopic results indicate the δ¹⁵N value of vegetable has strong relationship with the kinds of fertilizer applied.  For example, the vegetable fertilized with organic fertilizer exhibited the high δ¹⁵N value of about 19‰ (OF), which is similar to about 17‰ of organic fertilizer.  By contrast, the vegetable fertilized with chemical fertilizer presented the δ¹⁵N value of about 0‰ (CF), which is as low as that of chemical fertilizer.  In addition, the integrated result induced from the four treatments infers that this isotopic approach is applicable to discern the organic vegetable on the conditions that the nitrogen isotope compositions of vegetable and the applied organic fertilizer are simultaneously analyzed in the plantation and the δ¹⁵N value of vegetable is greater than that of the applied organic fertilizer.  Some further supplementary experiments, however, must be performed to let the isotopic approach be a highly authentic technique.

Key words:Nitrogen isotope, Certification of organic vegetable, Organic and Chemical fertilizers

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