Plant and Soil

, Volume 153, Issue 2, pp 295–304

Natural abundance of 15N in tropical plants with emphasis on tree legumes

  • T. Yoneyama
  • T. Muraoka
  • T. Murakami
  • N. Boonkerd
Article

Abstract

Natural abundance of 15N (δ 15N) of leaves harvested from tropical plants in Brazil and Thailand was analyzed. The δ 15N values of non-N2-fixing trees in Brazil were +4.5±1.9‰, which is lower than those of soil nitrogen (+8.0±2.2‰). In contrast, mimosa and kudzu had very low δ 15N values (−1.4≈+0.5‰). The δ 15N values of Panicum maximum and leguminous trees, except Leucaena leucocephala, were similar to those of non-N2-fixing trees, suggesting that the contribution of fixed N in these plants is negligible. The δ 15N values of non-N2-fixing trees in Thailand were +4.9±2.0‰. Leucaena leucocephala, Sesbania grandiflora, Casuarina spp. and Cycas spp. had low δ 15N values, close to the value of atmospheric N2 (0‰), pointing to a major contribution of N2 fixation in these plants. Cassia spp. and Tamarindus indica had high δ 15N values, which confirms that these species are non-nodulating legumes. The δ 15N values of Acacia spp. and Gliricidia sepium and other potentially nodulating tree legumes were, on average, slightly lower than those of non-N2-fixing trees, indicating a small contribution of N2 fixation in these legumes.

Key words

natural 15N abundance N2 fixation Panicum maximum tree legumes tropical ecosystem 

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Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • T. Yoneyama
    • 1
  • T. Muraoka
    • 2
  • T. Murakami
    • 3
  • N. Boonkerd
    • 3
  1. 1.Department of Soils and FertilizersNational Agriculture Research CenterTsukuba, IbarakiJapan
  2. 2.Centro de Energia Nuclear na AgriculturaUniversidade de Sao PauloPiracicabaBrasil
  3. 3.Soil Science DivisionDepartment of AgricultureBangkokThailand

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