Question

nitrogen accounts nearly 79% of the air. still nitrogen is the most limiting nutrients for plant growth. why ? explain the terms nitrification and denitrification

Answer 1

because the nitrogen is not in use able form plant takes liquid nitrogen for use not pure liquid but soluble in water

Answer 2

since nitrogen is most abundant gas in atmosphere not in earth crust and this thing we know that plant takes nutrition that is nitrogen from soil due to which they have to follow nitrogen cycle.
Nitrification is the process in which nitrogen is changed into nitrite and nitrate. These are the form of nitrogen which plant usually use.
Denitrification is the reverse of nitrification that is this process change nitrogenous compounds back to atmospheric nitrogen.