Certified Crop Advisor Practice Exam

What is the effect of compaction on soil aeration?

1. Improves aeration

2. Reduces aeration

3. Has no effect on aeration

4. Only affects surface aeration

The correct answer is: Reduces aeration

Compaction significantly reduces aeration in soil. When soil particles are compacted, the spaces between them, known as pore spaces, become smaller and can be reduced in number. These pore spaces are essential for air exchange and for the movement of oxygen and other gases between the soil and the atmosphere. Soil aeration is crucial for plant roots and soil microorganisms, which require adequate oxygen levels to thrive. Compacted soil limits the ability of air to penetrate deeply into the soil profile, leading to poorer conditions for root growth and function. Additionally, this reduction in aeration can lead to the accumulation of carbon dioxide and other gases, further impairing plant health. While some may believe that compaction might improve surface aeration, in reality, the overall aeration status of the soil is negatively impacted, especially in the root zones where it matters most for plant and microbial health.