Nitrogen is an essential component for the growth of plants but they cannot take it directly from the air. So how do they get the necessary nitrogen for growth?

Soil

Explanation:

Plants get their nitrogen from the soil. Although nitrogen is present in the air the structure of the molecule is strong and so would require large amounts of energy from the plant to break down.

The breaking down of nitrogen is a process called nitrogen fixation. Bacteria and archaea in the soil convert nitrogen into ammonia; breaking down the tough triple bond of nitrogen to be more readily absorbed by the plant.