International Journal of Agroforestry and Silviculture ISSN: 2375-1096 Vol. 10 (8), pp. 001-007, August, 2022. © International Scholars Journals

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.

Accepted 15 November 2022

Abstract

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 lucens, ¹⁵N natural abundance, semi arid lowland, biological nitrogen fixation, natural ecosystem.