| 摘要: | 全球有機農業興起，但在有機市場中常出現不實的有機產品，可見有機驗證之重要性。目前有機驗證可以檢測出農藥的殘留，但無有效快速方法來檢測出蔬菜是否施用化學肥料。有機質肥料的氮同位素組成δ15N大於化學肥料之δ15N值，因此，本研究採用萵苣(Lactuca sativa)、菠菜(Spinacia oleracea)、青江菜(Brassica chinensis)、高麗菜(Brassica oleracea var. capitate)、青花菜(Brassica oleracea var. italica)等五種市面常見之蔬菜作為供試材料，分別以三種不同肥料方式種植(無施肥、化學肥料、有機肥料)，收穫後將材料乾燥研磨成粉，進行碳(13C)和氮(15N)同位素分析。結果發現，施用有機肥料的萵苣及菠菜在播種後35天採收之δ15N含量顯著高於施用化學肥料；而青江菜在生長第20天後採收，δ15N含量在有機肥料與化學肥料種植下也具有顯著差異。植物光合作用及生長環境與δ13C相關，但無論施放有機肥料或化學肥料，δ13C含量在各種蔬菜採收後，皆不具顯著的差異。δ13C含量在不同肥料施放濃度下，也沒有呈現特定的趨勢，因此肥料無法影響δ13C含量，無法單一使用δ13C來鑑別有機肥料及化學肥料的差異。總之，δ15N值可辨別施用有機質肥料與化學肥料的差異，期望在未來δ15N可以成為有效快速辨別的驗證技術。
Organic agriculture becomes popular nowadays. However, chemical-fertilizer products often occur in the organic market and confuse with the genuine of organic products, which shows the importance of organic verification and authentication. At present, organic authorized legitimate can detect pesticide residues, but there is no effective and rapid method to detect whether chemical fertilizers are applied to vegetables. The nitrogen 15 isotopic composition (δ15N) of organic fertilizers is greater than chemical fertilizers, therefore, in our research, carbon 13 isotope (δ13C) and nitrogen 15 isotopic were used for analyzing various types of planting, including non-fertilizers, chemical fertilizers, and organic fertilizers. We planted five common vegetables from the markets, including Lactuca sativa, Spinacia oleracea, Brassica chinensis, Brassica oleracea var. capitate, and Brassica oleracea var. italic. After harvest, dried and ground leaf powders were used for the analysis of isotopes. The results show that δ15N of plants applied with organic fertilizers was significantly greater than those with chemical fertilizers. The difference between organic farming and conventional farming could be distinguished between L. sativa and S. oleracea harvested after 35 days of growth. Nevertheless, both organic farming and conventional farming were not able to be distinguished by the composition of the δ13C among the tested vegetables despite the δ13C related to the photosynthesis and growth environment of plants. In conclusion, we provide methods with δ15N composition to distinguish the difference between organic farming and conventional farming and expect to apply the effective and quick methodology of organic verification. |
