Measuring symbiotic nitrogen fixation by legumes
Date
2009
Authors
Peoples, M.
Unkovich, M.
Herridge, D.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Book chapter
Citation
Nitrogen fixation in crop production, 2009, vol.52, pp.125-170
Statement of Responsibility
Mark B. Peoples, Murray J. Unkovich and David F. Herridge
Conference Name
Abstract
This 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.