If nearly 79%of the atmosphere is made of nitrogen, how could there be a shortage of nitrogen in soil ?

There is a shortage of nitrogen in the soil because atmospheric nitrogen has limited use.

Explanation:

Atmospheric nitrogen is in the N2 form, this form is of limited use for biological processes and so there is an abundance of N2 in the atmosphere. However, the biological processes that occur in the soil need nitrogen in a form other than N2, that is, they need nitrogen converted to nitrite. These type molecules are not in abundance in the soil and for this reason, the soil has a shortage of this nutrient. Incorporating nitrogen into the soil requires chemical fertilization or biological nitrogen fixation.