Question:
Given below are two statements :
Statement (I) : At field capacity matric potential, the soil water content is higher when dry soil is getting wet.
Statement (II) : The drying of soil depends on the narrow radii of the connecting channels, whereas the wetting process depends on large pore diameters.
In light of the above statements, choose the most appropriate answer from the options given below.
Given below are two statements :
Statement (I) : At field capacity matric potential, the soil water content is higher when dry soil is getting wet.
Statement (II) : The drying of soil depends on the narrow radii of the connecting channels, whereas the wetting process depends on large pore diameters.
In light of the above statements, choose the most appropriate answer from the options given below.
Statement (I) : At field capacity matric potential, the soil water content is higher when dry soil is getting wet.
Statement (II) : The drying of soil depends on the narrow radii of the connecting channels, whereas the wetting process depends on large pore diameters.
In light of the above statements, choose the most appropriate answer from the options given below.
Show Hint
Remember the hysteresis rule:
\[ \theta_{\text{desorption (drying)}} > \theta_{\text{adsorption (wetting)}} \]
The drying curve always sits above the wetting curve on a soil water characteristic plot.
\[ \theta_{\text{desorption (drying)}} > \theta_{\text{adsorption (wetting)}} \]
The drying curve always sits above the wetting curve on a soil water characteristic plot.
Updated On: Jul 23, 2026
- Both Statement (I) and Statement (II) are true.
- Both Statement (I) and Statement (II) are false.
- Statement (I) is true but Statement (II) is false.
- Statement (I) is false but Statement (II) is true.
Show Solution
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
Soil water hysteresis describes the phenomenon where the relationship between soil water content ($\theta$) and matric potential ($\psi$) is not unique, but depends on whether the soil is drying (desorption) or wetting (adsorption).
For any given matric potential, the water content is higher during drying than during wetting.
Step 3: Detailed Explanation:
Let us analyze each statement:
Statement (I): "At field capacity matric potential, the soil water content is higher when dry soil is getting wet."
This statement is incorrect.
"Dry soil getting wet" represents the adsorption (wetting) process.
Because of hysteresis, the water content at any given matric potential is lower during wetting ($\theta_{\text{wetting}}$) than during drying ($\theta_{\text{drying}}$, "wet soil getting dry").
Therefore, the water content is lower when dry soil is getting wet.
Statement (II): "The drying of soil depends on the narrow radii of the connecting channels, whereas the wetting process depends on large pore diameters."
This statement is correct.
This is explained by the "ink-bottle" effect of soil pores.
An ink-bottle pore consists of a large main cavity (the body) with a narrow entrance (the neck).
During drying (desorption), the pore cannot empty until the matric suction increases enough to drain the narrow neck.
Thus, drying is controlled by the narrow radius of the neck.
During wetting (adsorption), the empty pore cannot fill completely until the suction decreases enough to allow water to enter the larger body cavity.
Thus, wetting is controlled by the larger radius of the pore body.
Step 4: Final Answer:
Statement (I) is false, but Statement (II) is true.
This corresponds to Option (D).
Soil water hysteresis describes the phenomenon where the relationship between soil water content ($\theta$) and matric potential ($\psi$) is not unique, but depends on whether the soil is drying (desorption) or wetting (adsorption).
For any given matric potential, the water content is higher during drying than during wetting.
Step 3: Detailed Explanation:
Let us analyze each statement:
Statement (I): "At field capacity matric potential, the soil water content is higher when dry soil is getting wet."
This statement is incorrect.
"Dry soil getting wet" represents the adsorption (wetting) process.
Because of hysteresis, the water content at any given matric potential is lower during wetting ($\theta_{\text{wetting}}$) than during drying ($\theta_{\text{drying}}$, "wet soil getting dry").
Therefore, the water content is lower when dry soil is getting wet.
Statement (II): "The drying of soil depends on the narrow radii of the connecting channels, whereas the wetting process depends on large pore diameters."
This statement is correct.
This is explained by the "ink-bottle" effect of soil pores.
An ink-bottle pore consists of a large main cavity (the body) with a narrow entrance (the neck).
During drying (desorption), the pore cannot empty until the matric suction increases enough to drain the narrow neck.
Thus, drying is controlled by the narrow radius of the neck.
During wetting (adsorption), the empty pore cannot fill completely until the suction decreases enough to allow water to enter the larger body cavity.
Thus, wetting is controlled by the larger radius of the pore body.
Step 4: Final Answer:
Statement (I) is false, but Statement (II) is true.
This corresponds to Option (D).
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