How does soil compaction influence infiltration and runoff?

How does soil compaction influence infiltration and runoff?

• A. Soil compaction has no effect on infiltration.
• B. Soil compaction reduces infiltration by decreasing pore space and increases surface runoff.
• C. Soil compaction increases infiltration.
• D. Soil compaction reduces surface runoff.

Answer: (B)

Soil compaction reduces the spaces in the soil that water can occupy, which lowers infiltration rates. When the soil becomes compacted, its porosity and the size of pathways for water movement (especially macropores) shrink. This makes it harder for water to move downward into the soil, so the rate at which rainfall can infiltrate is diminished. With infiltration slower than the rate of rainfall, more water stays on the surface and becomes surface runoff. In short, compacted soil restricts water entry, leading to higher runoff after rain. The other ideas—no effect, infiltration increasing, or runoff decreasing—don’t fit because they contradict the way reduced pore space and blocked flow paths change the soil’s ability to absorb water.

Soil compaction reduces the spaces in the soil that water can occupy, which lowers infiltration rates. When the soil becomes compacted, its porosity and the size of pathways for water movement (especially macropores) shrink. This makes it harder for water to move downward into the soil, so the rate at which rainfall can infiltrate is diminished. With infiltration slower than the rate of rainfall, more water stays on the surface and becomes surface runoff. In short, compacted soil restricts water entry, leading to higher runoff after rain. The other ideas—no effect, infiltration increasing, or runoff decreasing—don’t fit because they contradict the way reduced pore space and blocked flow paths change the soil’s ability to absorb water.