Question

The pF curve is same as

• A. Moisture - density relation
• B. Soil temperature - water relation
• C. Soil pH- base saturation relation
• D. Soil water content - matric potential relation

Hint:

Key pF values: - $pF = 0$: Saturation ($1\text{ cm}$ head) - $pF = 54$: Field Capacity ($346\text{ cm}$ head or $1/3\text{ bar}$) - $pF = 18$: Permanent Wilting Point ($15,848\text{ cm}$ head or $15\text{ bar}$) - $pF = 7.0$: Oven-dry soil ($10,000,000\text{ cm}$ head or $10,000\text{ bar}$)

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The energy state of soil water is characterized by the matric potential.
The graphical representation of soil water content plotted against matric potential is called the soil water characteristic curve (or moisture release curve).

Step 2: Detailed Explanation:
- The term "pF" was introduced by Schofield (1935) to simplify water potential values.
- It is defined as the common logarithm of the matric suction head ($h$) expressed in centimeters of water:
\[ pF = \log_{10} |h| \] - Therefore, a pF curve plots the logarithm of matric potential against the soil water content.
- This is synonymous with the soil water content - matric potential relationship.

Step 3: Final Answer:
The pF curve is the soil water content - matric potential relation.