How can nitrogen be fixed naturally for plant use?
Nitrogen fixation is a process by which nitrogen in the atmosphere is converted into ammonia.
Nitrogen fixation occurs naturally in the soil by nitrogen fixing bacteria.
Some nitrogen fixing bacteria ( Rhizobia ) have a symbiotic relationship with plants.
Non symbiotic nitrogen fixing by bacteria ( Azospirilum ) also occurs in cases like rice roots.
Prokaryotic micro organisms that can fix nitrogen are called diazotrophs.
All biological nitrogen fixation is done by the enzyme nitrogenase which contains a metallic component ( iron ,molybdenum and vanadium ) .
Nitrogen fixation also occurs naturally in the air by means of lightning.