Question

What will happen when Nitrogen is not present in our Earth ??????

Answer 1

Since all protein contains nitrogen, it's absence would cause instant death. And since N2 constitutes 79% of the air with the balance oxygen, whatever was left after the N2 disappeared, would be in a world of essentially pure oxygen. ... The atmosphere wouldbecome mainly low pressure oxygen.

Answer 2

Hey mate
Here is your answer
If there was no nitrogen in the atmosphere and no other inert gas to replace it, you would flame out into non-existence. None of the metabolic processes common to vegetative life would exist.

Think of the atmosphere effects of an. oxy-acetylene cutting torch the moment the acetylene is turned off.
I hope it will help you