Nitrogen fixation. into ammonia, which is metabolized by most organisms. Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria such as Azotobacter and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.Click to see full answer. Also, how is nitrogen fixed?Nitrogen is fixed, or combined, in nature as nitric oxide by lightning and ultraviolet rays, but more significant amounts of nitrogen are fixed as ammonia, nitrites, and nitrates by soil microorganisms. More than 90 percent of all nitrogen fixation is effected by them.Also, which plant fixes nitrogen into soil? Category:Nitrogen-fixing crops. Plants that contribute to nitrogen fixation include the legume family – Fabaceae – with taxa such as clover, soybeans, alfalfa, lupins, peanuts, and rooibos. People also ask, why is nitrogen fixation important? Nitrogen fixation is a process whereby bacteria in the soil convert atmospheric nitrogen ( N2 gas) into a form that plants can use. The reason this process is so important is that animals and plants cannot use atmospheric nitrogen directly. Bacteria convert it into ammonium ( NH4+ ), which then plants can absorb.How does lightning fix nitrogen into the soil?Nitrogen in the atmosphere can be transformed into a plant-usable form, a process called nitrogen fixation, by lightning. The nitrates fall to the ground in raindrops and seep into the soil in a form that can be absorbed by plants. Lightning does add nitrogen to the soil, as nitrates dissolve in precipitation.