Editing Nitrogen fixation (section)

====Legume family====
[[Image:Root nodules on fava bean plant.jpg|thumb|right|Nodules are visible on this broad bean root]]
Plants that contribute to nitrogen fixation include those of the [[legume]] [[family (biology)|family]]—[[Fabaceae]]— with [[taxa]] such as [[kudzu]], [[clover]], [[soybean]], [[alfalfa]], [[lupin]], [[peanut]] and [[rooibos]].<ref name="Mus-2016" /> They contain [[symbiosis|symbiotic]] [[rhizobia]] bacteria within [[root nodule|nodules]] in their [[root|root systems]], producing nitrogen compounds that help the plant to grow and compete with other plants.<ref>{{cite journal | vauthors = Kuypers MM, Marchant HK, Kartal B | title = The microbial nitrogen-cycling network | journal = Nature Reviews. Microbiology | volume = 16 | issue = 5 | pages = 263–276 | date = May 2018 | pmid = 29398704 | doi = 10.1038/nrmicro.2018.9 | hdl = 21.11116/0000-0003-B828-1 | s2cid = 3948918 | hdl-access = free }}</ref> When the plant dies, the fixed nitrogen is released, making it available to other plants; this helps to fertilize the [[soil]].<ref name=postgate/><ref>{{cite book | vauthors = Smil V |year=2000 |title=Cycles of Life |publisher=Scientific American Library}}</ref> The great majority of legumes have this association, but a few [[genera]] (e.g., ''[[Styphnolobium]]'') do not. In many traditional farming practices, fields are [[Crop Rotation|rotated]] through various types of crops, which usually include one consisting mainly or entirely of [[clover]].{{citation needed|date=August 2019}}

Fixation efficiency in soil is dependent on many factors, including the [[legume]] and air and soil conditions. For example, nitrogen fixation by red clover can range from {{convert|50|to|200|lb/acre|abbr=on}}.<ref>{{Cite web|url=http://www1.foragebeef.ca/$Foragebeef/frgebeef.nsf/all/frg90/$FILE/fertilitylegumefixation.pdf|title=Nitrogen Fixation and Inoculation of Forage Legumes|archive-url=https://web.archive.org/web/20161202170130/http://www1.foragebeef.ca/$Foragebeef/frgebeef.nsf/all/frg90/$FILE/fertilitylegumefixation.pdf|archive-date=2 December 2016|url-status=dead}}</ref>