TeXes Science Practice Test

Which type of soil would be least able to hold water or allow it to pass through?

1. Soil with a high percentage of sand

2. Soil with a high percentage of humus

3. Soil with a high percentage of clay

4. Soil with a high percentage of silt

The correct answer is: Soil with a high percentage of clay

Soil with a high percentage of clay is indeed the correct answer when considering the ability to hold water or allow it to pass through. Clay particles are very small and have a high surface area, which contributes to their ability to retain water. They can hold water tightly due to their flat structure and plate-like shape, leading to reduced drainage. This property means that clay soil can become saturated, making it difficult for water to pass through, while also leading to poor aeration. In contrast, sandy soil consists of larger particles that create large spaces between them, allowing water to drain quickly and making it difficult for the soil to retain moisture. Soil with a high percentage of humus is known for its water-retaining properties, enhancing the soil's ability to hold moisture. Silt, while better at retaining moisture than sand, still drains more efficiently than clay. Thus, clay soil is characterized by its ability to retain water rather than allow it to pass through, confirming that it has the least ability to manage water effectively in comparison to the other soil types mentioned.