https://www.differencebetween.com/difference-between-nitrogen-fixation-and-nitrification/

Dr Kristine Petrosyan thank you for your contribution to the discussion

Nitrogen-fixing bacteria are microorganisms that turn atmospheric nitrogen into a usable form for plants and other organisms, while nitrifying bacteria convert ammonia into nitrite and nitrate. The nitrogen cycle is the overall process of nitrogen conversion and recycling in the environment, including nitrogen fixation, nitrification, denitrification, and ammonification. Nitrogen fixation specifically refers to the conversion of atmospheric nitrogen into ammonia or nitrate by nitrogen-fixing bacteria. In simpler terms, nitrogen-fixing bacteria make nitrogen usable, nitrifying bacteria convert ammonia into a less toxic form, and the nitrogen cycle is the complete cycle of nitrogen changing forms in nature.

Dr Sudip Ghimire thank you for your contribution to the discussion

The nitrifying bacteria are nitrogen-fixing bacteria. They are autotrophic organisms as they produce their food on their own by conversion of nitrogen into ammonia or other forms. They absorb the atmospheric nitrogen and then utilize it to obtain energy by oxidation processes. The key difference between nitrogen fixation and nitrification is that the nitrogen fixation is the process of converting atmospheric nitrogen into ammonium ions while the nitrification is the process of converting ammonium ions into nitrite or nitrate ions. Nitrogen-fixing bacteria in the soil and within the root nodules of some plants convert nitrogen gas in the atmosphere to ammonia. Nitrifying bacteria convert ammonia to nitrites or nitrates.Nitrifying bacteria convert the most reduced form of soil nitrogen, ammonia, into its most oxidized form, nitrate. In itself, this is important for soil ecosystem function, in controlling losses of soil nitrogen through leaching and denitrification of nitrate. Nitrogen Cycle can convert atmospheric nitrogen into usable forms. Therefore, nitrogen fixation is this conversion process of atmospheric nitrogen into ammonium ions in the soil. Furthermore, symbiotic and free-living bacteria are mainly involved in nitrogen fixation. Nitrogen fixation, any natural or industrial process that causes free nitrogen, which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites nitrogen cycle. Nitrogen fixation is a chemical process that converts atmospheric nitrogen into ammonia, which is absorbed by organisms. Nitrogen fixation is essentially converting atmospheric nitrogen into a form that plants can more readily utilize.