Question

The permanent wilting point of soil corresponds approximately to which soil moisture tension?

• A. 0.33 bar
• B. 1 bar
• C. 10 bars
• D. 15 bars

Hint:

Remember: Field capacity is around 0.33 bar, while permanent wilting point is around 15 bars.

Answer 1

The Correct Option is D

The term "permanent wilting point" (PWP) in soil science refers to the moisture content level at which plants can no longer extract sufficient water, leading them to wilt and potentially die if conditions persist. This concept is crucial in understanding plant-soil-water relationships, especially in the context of irrigation management and hydrology.

The soil moisture tension, often measured in bars, describes the energy required for plants to extract water from the soil. The permanent wilting point (PWP) corresponds to the soil moisture tension at which plants can no longer extract water. The generally accepted value for this tension is 15 bars.

Let's evaluate the given options in relation to the permanent wilting point:

• 0.33 bar: This value is typically associated with field capacity, the point at which soil moisture content is high, and drainage beyond this point is minimal.
• 1 bar: While higher than field capacity, this level is not associated with the wilting point.
• 10 bars: Represents a high tension but is still below the generally accepted value for permanent wilting.
• 15 bars: This is the accepted soil moisture tension for the permanent wilting point, indicating it as the correct answer.

In conclusion, the permanent wilting point of soil corresponds approximately to a soil moisture tension of 15 bars.