The least porous soil among the following is a:

Options

A. Clay soil
B. Sandy soil
C. Loam soil
D. Gravelly soil

Answer

To determine the least porous soil among the given options (clay soil, sandy soil, loam soil, and gravelly soil), we can follow these steps:

### Step 1: Understand Soil Porosity
Porosity refers to the amount of empty space (pores) within the soil that can hold air or water. The size of the soil particles greatly influences porosity.

### Step 2: Analyze the Soil Types
1. **Gravelly Soil**: Composed of large particles. It has high porosity because the larger gaps between the particles allow water to drain quickly.
2. **Sandy Soil**: Made up of medium-sized particles. It also has relatively high porosity, allowing water to drain but not as quickly as gravelly soil.
3. **Loamy Soil**: A mixture of sand, silt, and clay. It has moderate porosity, retaining some water while allowing drainage.
4. **Clayey Soil**: Composed of very small particles. It has low porosity because the tiny particles pack closely together, leaving little space for air or water.

### Step 3: Compare the Porosity of Each Soil Type
- Gravelly soil: High porosity
- Sandy soil: Moderate to high porosity
- Loamy soil: Moderate porosity
- Clayey soil: Low porosity

### Step 4: Identify the Least Porous Soil
Based on the analysis, clayey soil has the smallest particle size and the least amount of pore space. Therefore, it is the least porous soil among the options provided.

### Conclusion
The least porous soil among the following is **clayey soil**.

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