Question

What will be the soil texture if it contains 60% clay, 20% silt, and 20% sand particles ?

• A. Sandy clay
• B. Clayey
• C. Silty loam
• D. Loamy sand

Hint:

Clay particles have the smallest diameter ($< 0.002 \text{ mm}$) and the highest specific surface area, which gives clayey soils high water-holding capacity and high cation exchange capacity (CEC).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Soil texture refers to the relative proportions of sand, silt, and clay mineral particles in a soil mass.
The USDA soil texture triangle is used to determine the exact textural class based on these proportions.

Step 3: Detailed Explanation:
Let us locate the textural class using the given proportions on the USDA soil texture triangle:
- Clay content: $60\%$
- Silt content: $20\%$
- Sand content: $20\%$
The sum of sand, silt, and clay is:
\[ 60\% + 20\% + 20\% = 100\% \]
On the USDA soil texture triangle:
- Any soil containing more than $40\%$ clay is classified under the Clay (or Clayey) textural class.
- More specifically, when clay is $60\%$, sand is $20\%$, and silt is $20\%$, the intersection point lies deep within the "Clay" textural field.
Let us review the other options:
- Sandy clay typically contains $35\text{ to }55\%$ clay and $45\text{ to }65\%$ sand.
- Silty loam typically contains less than $27\%$ clay and more than $50\%$ silt.
- Loamy sand typically contains $70\text{ to }90\%$ sand and less than $15\%$ clay.
Therefore, a soil with $60\%$ clay is classified as clayey.

Step 4: Final Answer:
The soil texture is Clayey, corresponding to option (B).