Question

In the International Union of Soil Science classification system, fine sand has a size range of

• A. 0.2 - 0 mm
• B. 0.02 - 0.2 mm
• C. 0.002 - 0.02 mm
• D. $<$0.002 mm

Hint:

Remember the key difference: USDA classifies silt as $0.002 \text{ to } 0.05\text{ mm}$ and sand as $0.05 \text{ to } 0\text{ mm}$, whereas the IUSS system uses a consistent factor of 10 ($0.002 \rightarrow 0.02 \rightarrow 0.2 \rightarrow 0$).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Soil texture refers to the relative proportions of sand, silt, and clay particles.
Different classification schemes, such as the USDA and the International Union of Soil Science (IUSS/Atterberg), define particle size boundaries differently.

Step 2: Detailed Explanation:
According to the International Union of Soil Science (IUSS) system, the soil separates are classified as:
- Coarse Sand: $0.2 \text{ to } 0\text{ mm}$
- Fine Sand: $0.02 \text{ to } 0.2\text{ mm}$
- Silt: $0.002 \text{ to } 0.02\text{ mm}$
- Clay: $< 0.002\text{ mm}$

Step 3: Final Answer:
In the IUSS system, the size range for fine sand is $0.02 \text{ to } 0.2\text{ mm}$.