African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6578

Full Length Research Paper

Symbiotic nitrogen fixation and nitrogen budget of Brazilian soybean [Glycine max (L.) Merril] varieties introduced in Benin using 15N isotopic dilution method

Charlotte C. ZOUNDJI
  • Charlotte C. ZOUNDJI
  • Laboratoire de Microbiologie des Sols et d’Ecologie Microbienne/Faculté des Sciences Agronomiques/UAC (LMSEM/FSA), Campus d’Abomey-Calavi, 01 BP 526 Cotonou, Bénin.
  • Google Scholar
Pascal HOUNGNANDAN
  • Pascal HOUNGNANDAN
  • Laboratoire de Microbiologie des Sols et d’Ecologie Microbienne/Faculté des Sciences Agronomiques/UAC (LMSEM/FSA), Campus d’Abomey-Calavi, 01 BP 526 Cotonou, Bénin.
  • Google Scholar
Félix A. KOUELO
  • Félix A. KOUELO
  • Laboratoire de Microbiologie des Sols et d’Ecologie Microbienne/Faculté des Sciences Agronomiques/UAC (LMSEM/FSA), Campus d’Abomey-Calavi, 01 BP 526 Cotonou, Bénin.
  • Google Scholar
Frechno E. BOKO
  • Frechno E. BOKO
  • Laboratoire de Microbiologie des Sols et d’Ecologie Microbienne/Faculté des Sciences Agronomiques/UAC (LMSEM/FSA), Campus d’Abomey-Calavi, 01 BP 526 Cotonou, Bénin.
  • Google Scholar
Joseph J. ADU-GYAMFI
  • Joseph J. ADU-GYAMFI
  • Soil and Water Management and Crop Nutrition Laboratory (SWMCNL) at the International Atomic Energy Agency (IAEA), Vienna International Centre, P. O. Box, 1400 Vienna, Austria.
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  •  Received: 03 April 2015
  •  Accepted: 09 December 2015
  •  Published: 07 January 2016

Abstract

Nitrogen-15 isotopic dilution method was used to estimate biological nitrogen fixation (BNF) and nitrogen (N) budget of fourteen (14) soybean varieties using maize as reference crop. The experiment was carried out at Sekou in Southern Benin. The amount of N derived from air (Ndfa kg N ha-1) ranged from 51 for variety BRS 261 to 148 for variety Canarana. In a scenario where the soybean shoot dry matter and grains were removed from the field after harvest and only the fallen leaves were incorporated into the soil, the N budget ranged between -91 (Canarana) and -17 kg N ha-1 (BRS 260). When only soybean grain was exported from the fields and fallen leaves and shoot dry matter are incorporated into the soil, the N budget varied from 7 (BRS 261) to 74 kg N ha-1 (BRS Garantia). The study showed that Canarana, TGX 1448 2E and BRS Paraiso soybean varieties fixed the highest amount of N among the 14 varieties. The inclusion of those soybean varieties in cereal-based cropping systems would help reduce N inputs and improve soil and crop productivity in farming systems in Benin. 
 
Key words: 15N enrichment technique, N2 fixation, N balance, soil fertility, Benin.