Nitrogen fixation is the process by which certain bacteria convert nitrogen gas from the air into a type of nitrogen that plants can use to grow. Full definition
For years, scientists have tried to increase the rate of nitrogen fixation in legumes by altering rhizobia bacterioid function or interactions that take place between the bacterioid and the root nodule cells. (sciencedaily.com)
There have been many claims of nitrogen fixation in plants outside nodules where it was known to occur for more than a century. (science.sciencemag.org)
Also, the impact of biological nitrogen fixation on N2O emissions is important in assessing the impact of cropping system changes. (usask.ca)