Soil aeration refers to –

Correct option is D

· Soil Aeration: It refers to the process of exchange of gases (oxygen and carbon dioxide) between the soil pores and the atmosphere.
· Importance of Soil Aeration:
· Ensures sufficient oxygen supply to plant roots for respiration.
· Facilitates the removal of CO₂ and other harmful gases from the soil.
· Improves root growth and microbial activity in the soil.
· Mechanisms of Soil Aeration:
· Natural diffusion of gases.
· Mechanical intervention such as tillage or plowing.
· Other Options Explained:
· (a) Drying of soil: Not directly related to aeration.
· (b) Flow of air over soil surface: Does not address gas exchange within soil pores.
· (c) Release of gases from soil: A result of microbial activity but not the definition of aeration.
· Therefore, exchange of oxygen and CO₂ between soil pore space and atmosphere (Option D) is the correct answer.