Submitted to: Nitrogen in Agricultural Soils, 2nd Edition
Publication Type: Book / Chapter
Publication Acceptance Date: May 1, 2005
Publication Date: June 1, 2008
Citation: Russelle, M.P. 2008. Biological dinitrogen fixation in agriculture. In: Schepers, J.S., Raun, W.R., editors. Nitrogen in Agricultural Systems. Madison, WI: ASA-CSSA-SSSA. Agronomy Monograph. 49:281-359. Technical Abstract: Dinitrogen gas can be converted to ammonia-N by prokaryotic bacteria, which are responsible for fixing most of the N in organic N on Earth. Some of these bacteria form symbioses with legumes in specialized root or stem nodules, whereas others proliferate in the rhizosphere or are endophytic in vascular tissue. This chapter describes these organisms, nodule formation, the enzymatic process of biological nitrogen fixation (BNF), and nitrogen assimilation by the plant. Methods of estimating BNF are described in detail as are environmental factors that influence the rate of fixation. Estimates of annual BNF are provided for both temperate and tropical forage and pulse legumes. The pathways of nitrogen transfer from legume to nonlegume and factors affecting transfer are detailed as are approaches for plant selection for BNF. Also discussed are the production, use, and effects of rhizobial inoculants.