Submitted to: Alfalfa National Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2004
Publication Date: December 15, 2004
Repository URL: http://www.ars.usda.gov/sp2UserFiles/Place/36401000/2004/Russelle.pdf
Citation: Russelle, M.P. 2004. Environmental impacts of N2 fixation by alfalfa. In: Proceedings of the Alfalfa National Symposium, December 13-15, 2004, San Diego, California. p. 57-62. Technical Abstract: Symbiotic N2 fixation by alfalfa provides substantial amounts of nitrogen (N) to livestock operations, subsequent crops, and soil organic matter. Fixed N can be a pollutant if alfalfa is not managed well. Symbiotic N2 fixation is an adaptive process that declines as other N supplies increase. Well-managed stands of alfalfa effectively absorb mineralized N from manure and remove residual nitrate from the subsoil, irrigation water, and shallow ground water, and fix less N from the air. Although N losses can occur both during and after alfalfa production, it is possible to use this adaptive N2 fixation process to reduce excess N supplies on farms.