Peoples, M.Unkovich, M.Herridge, D.2010-06-032010-06-032009Nitrogen fixation in crop production, 2009, vol.52, pp.125-1709780891181705http://hdl.handle.net/2440/58647This chapter provides a brief overview of the methodologies that have been used to quantify N<inf>2</inf> fixation of legumes and then focuses in more detail on the particular ones that people believe are likely to be of most value for quantifying N<inf>2</inf> fixation by field-grown legumes. It is possible to quantify legume N<inf>2</inf> fixation by simply measuring the total amount of N accumulated during a given period of time, provided the plants are grown in N-free rooting medium such as coarse sand under controlled conditions and are supplied with all essential nutrients except combined N. The chapter describes many of the methodologies to separate legume total N into two components: that fraction of plant N taken up from the soil and that derived from the fixation of atmospheric N<inf>2</inf>. Other approaches attempt to quantify N<inf>2</inf> fixation by measuring the rate of activity of nitrogenase, the N<inf>2</inf>-fixing enzyme in root nodules.enMeasuring symbiotic nitrogen fixation by legumesBook chapter002009756710.2134/agronmonogr52.c62-s2.0-8510291325334297Unkovich, M. [0000-0003-3151-6918]