Which statement best describes soil compaction?

Which statement best describes soil compaction?

• A. It increases porosity
• B. It reduces pore space
• C. It leaves air pockets unchanged
• D. It increases water infiltration

Answer: (B)

Soil compaction tightens the soil structure by pressing particles closer together, which reduces the spaces between them that hold air and water. Porosity is the portion of soil volume made up of these pore spaces, so when particles are packed more tightly, porosity decreases and pore space shrinks. With less space and fewer connected pathways, water movement slows and air exchange is limited, so infiltration tends to decrease. That’s why describing compaction as reducing pore space is the most accurate. Increasing porosity would require looser soil; air pockets aren’t left unchanged but are compressed; and water infiltration doesn’t increase under compaction.

Soil compaction tightens the soil structure by pressing particles closer together, which reduces the spaces between them that hold air and water. Porosity is the portion of soil volume made up of these pore spaces, so when particles are packed more tightly, porosity decreases and pore space shrinks. With less space and fewer connected pathways, water movement slows and air exchange is limited, so infiltration tends to decrease. That’s why describing compaction as reducing pore space is the most accurate. Increasing porosity would require looser soil; air pockets aren’t left unchanged but are compressed; and water infiltration doesn’t increase under compaction.