Plants need nitrogen in order to survive. the problem is they cannot take in the atmospheric nitrogen, but instead must rely on a certain class of bacteria that are able to turn atmospheric nitrogen into other nitrogen compounds, such as ammonia and nitrates. what is the name of this process?

Nitrogen fixation is the name of the process in which the atmospheric dinitrogen is converted into a form which can be used by the plants for their growth. The nitrogen fixation is done by a soil bacteria called as rhizobia which lives in symbiotic association with the root nodules of the leguminous plants. The bacteria converts the atmospheric dinitrogen into ammonia and nitrates which are readily absorbed by the plants. In return the the bacteria obtains the carbohydrates from the plants as a source of food.