Question

Arrange the following soil texture with decreasing field capacity water content.
(A) Sandy loam
(B) Sandy
(C) Silty loam
(D) Clay
E) Clay loam
Choose the correct answer from the options given below :

• A. (A), (B), (C), (D), (E)
• B. (A), (C), (D), (E), (B)
• C. (B), (A), (C), (E), (D)
• D. (D), (E), (C), (A), (B)

Hint:

To solve textural sequence questions quickly:
- Fine textures (Clay) always have the highest water retention.
- Coarse textures (Sand) always have the lowest water retention.
Identifying (D) as the highest and (B) as the lowest immediately points to Option (D).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Field capacity is the amount of water remaining in the soil after excess gravitational water has drained away and the rate of downward movement has significantly decreased (typically occurring 2 to 3 days after a rain or irrigation event, at a matric potential of $-0.1$ to $-0.33\text{ bar}$).
The water held at field capacity depends on the soil's texture, specifically its pore-size distribution and surface area.

Step 3: Detailed Explanation:
Let us analyze how soil texture affects water retention:
Finer-textured soils contain more clay particles, which have a high specific surface area and a large volume of narrow micropores.
These micropores exert strong capillary forces that hold onto water against the pull of gravity.
Coarser-textured soils contain more sand particles, which have a low surface area and a large volume of macropores that drain easily.
Therefore, field capacity water content increases as the clay content increases.
Let us arrange the given soil textures from highest clay content (finest) to lowest clay content (coarsest):
1. (D) Clay: holds the most water due to its high clay and micropore content.
2. (E) Clay loam: contains moderate clay and moderate sand/silt.
3. (C) Silty loam: holds moderate water, dominated by silt particles.
4. (A) Sandy loam: contains high sand content, holding less water.
5. (B) Sandy: holds the least water due to its large macropores and low surface area.
Thus, the decreasing order of field capacity water content is: (D) $\rightarrow$ (E) $\rightarrow$ (C) $\rightarrow$ (A) $\rightarrow$ (B).

Step 4: Final Answer:
The correct decreasing sequence is (D), (E), (C), (A), (B).
This matches Option (D).