Question

Textural triangle of ISSS model contains

• A. 4 textural classes
• B. 8 textural classes
• C. 12 textural classes
• D. 16 textural classes

Hint:

Textural classes:
USDA Model = 12 textural classes.
ISSS Model = 8 textural classes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Soil particle size fractions are mapped onto equilateral triangular diagrams to classify soil textures into distinct grouping classes.

Step 2: Detailed Explanation:
In soil science textural classification systems:
- USDA Textural Triangle: Uses USDA particle size fractions (Clay $< 0.002$ mm, Silt $0.002-0.05$ mm, Sand $0.05-2.0$ mm) and divides the triangle into 12 textural classes.
- ISSS (International Society of Soil Science) Model: Uses Atterberg particle limits (Clay $< 0.002$ mm, Silt $0.002-0.02$ mm, Fine Sand $0.02-0.2$ mm, Coarse Sand $0.2-2.0$ mm) and simplifies soil classification into 8 standard textural classes: Sand, Loamy Sand, Sandy Loam, Loam, Silt Loam, Sandy Clay, Clay Loam, and Clay.

Step 3: Final Answer:
Therefore, the ISSS textural triangle model contains 8 textural classes, corresponding to option (B).