African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12485

Full Length Research Paper

Estimates of biological nitrogen fixation by Pterocarpus lucens in a semi arid natural forest park in Senegal using 15N natural abundance method

Sylla S N1*, Ndoye I1, Gueye M2, Ba A T1 and Dreyfus B3
  1UCAD, Faculté des Sciences et Techniques, Département de BV, BP 5005, Dakar, Sénégal. 2MIRCEN/Centre ISRA-IRD, BP 1386, Dakar, Sénégal. 3LSTM, IRD _ CIRAD, TA10/J, Campus de Baillarguet, 34398, Montpellier, France
Email: [email protected]

  •  Accepted: 15 November 2002
  •  Published: 30 December 2002



Nitrogen (N2) fixation by Pterocarpus lucens in a natural semi arid ecosystem, in Ferlo, Senegal was estimated using 15N natural abundance (∂15N) procedure. Other non-fixing trees accompanying P. lucens in the same area were also investigated as control. Results showed an important variation of ∂15N in leaves between the nitrogen-fixing tree (P. lucens) and reference plants, whereas no significant differences were recorded in amount of nitrogen (%). The relative ∂15N values (‰) were higher in non-fixing plants than in fixing plants considered. Calculations of %Ndfa gave rates ranging between 26% and 49%. The values of %Ndfa depend largely on soil and the reference plants. The contribution of nitrogen derived from fixation in leaves reached 28.9 kg.N/ha and 10.8 kg.N/ha in ferruginous and in sandy soil respectively.

Key words: Pterocarpus lucens15N natural abundance, semi arid lowland, biological nitrogen fixation, natural ecosystem