Subtopic: Measurement of infiltration, soil moisture and irrigation water infiltration
Question Statement:
A tensiometer is suitable for measuring soil moisture tension up to a maximum limit of approximately:
Options:
(A) $0.85\text{ bar}$ ($85\text{ kPa}$)
(B) $15\text{ bar}$ ($1500\text{ kPa}$)
(C) $31\text{ bar}$ ($3100\text{ kPa}$)
(D) $100\text{ bar}$
Answer Key:
A
Step-by-Step Solution & Explanation
A tensiometer operates by measuring the vacuum created in a sealed water column. When soil water tension exceeds roughly $0.80 - 0.85\text{ bar}$ ($80 - 85\text{ kPa}$), cavitation/air entry occurs in the porous ceramic cup, breaking the water column and disabling the gauge.