title: Annual variation of natural 15N abundance in tea leaves and its practicality as an organic tea indicator.
abstract: To obtain basic knowledge about the relationship between the application of organic fertilizers and the δ15N values of leaves of organically grown tea plants, annual variations in the δ15N values of the tea leaves were investigated. Although variations did not immediately arise after the application of organic fertilizers, differences in the δ15N values between organic and conventional cultivations appeared basically after three years from the beginning of the organic cultivation except when an organic fertilizer with a low δ15N value was applied, and the variation depended on the δ15N values of the fertilizers. In addition, the effectiveness of the δ15N values as a practical indicator of organic teas was examined. The tea leaves collected from organic farms did not always have higher δ15N values than the commercially available nonorganic teas. This result demonstrates that it is not easy to discriminate organic teas from nonorganic teas simply by their δ15N values.
authors: National Institute of Vegetable and Tea Science, National Agriculture and Food Research Organization (NARO), 2769 Kanaya, Shimada, Shizuoka 428-8501, Japan. hayn@affrc.go.jp
authors: Nobuyuki
authors: N
authors: Hayashi
authors: Tomomi
authors: T
authors: Ujihara
authors: Eri
authors: E
authors: Tanaka
authors: Yasuhiro
authors: Y
authors: Kishi
authors: Hideyuki
authors: H
authors: Ogawa
authors: Hirofumi
authors: H
authors: Matsuo
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry* / Q000145:classification*; D058870:Food, Organic / Q000032:analysis / Q000145:classification*; D009587:Nitrogen Isotopes / Q000032:analysis*; D058871:Organic Agriculture; D018515:Plant Leaves / Q000737:chemistry*; D012621:Seasons
chemical_list: D009587:Nitrogen Isotopes