In what ways is nitrogen added and removed from the soil.     

Ways is nitrogen added  to the soil

1. industrial fixation e.g., Haber process
2. mutualistic blue- green bacteria e.g., Rhizobium e.g. legume
3. free- living blue- green bacteria e.g. Azobacter, clostridium
4. Action of lighting etc. on oxygen and nitrogen.
5. Manure addition
6. plant residues
7. dead animals

Ways nitrogen is removed from soil

1. Bacteria change nitrate in the soil to atmospheric nitrogen, which joins the atmosphere in low-aerated, water-logged soils.
2. Turns urea fertilizers and manures on the soil surface into gases that also join the atmosphere.
3. Leaching
4. Erosion