Nitrogen in the air is actually formed as two atoms of Nitrogen "triple bonded" together. This is very strong and hard to break into each individual atom of nitrogen.
Soil bateria use atmospheric Nitrogen to eat and as a result they can break the "triple bond" leaving Nitrogen in other forms which the plant can use.
UnitAlFa t1_iui4gn5 wrote
Reply to ELI5 Why can’t plants absorb nitrogen from the air? by Cool-Boy57
Nitrogen in the air is actually formed as two atoms of Nitrogen "triple bonded" together. This is very strong and hard to break into each individual atom of nitrogen.
Soil bateria use atmospheric Nitrogen to eat and as a result they can break the "triple bond" leaving Nitrogen in other forms which the plant can use.