Soil water tension corresponding to the upper plastic limit aligns with a pF value of:
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Answer: D. 0.5
Explanation
The upper plastic limit of soils corresponds to a low moisture tension near a pF value of 0.5. This specific pF threshold indicates the minimal suction required to reach plastic deformation behavior. At this moisture level, soil behaves like a malleable putty rather than a rigid solid. The pF scale expresses soil water potential as the logarithm of the height of a water column in centimeters. Atterberg limits define critical moisture boundaries for fine-grained cohesive soils and clays. Plastic limits mark the boundary where soil transitions from a semisolid to a plastic state.
Civil engineers utilize Atterberg limits and pF metrics to evaluate foundation stability and roadbeds. Agricultural engineers monitor plastic limits to avoid tilling soils when compaction risks peak. Understanding soil moisture tension curves prevents catastrophic structural damage during construction. Option A represents a pF value of 1, which corresponds to ten centimeters of water tension. Option B represents a pF value of 2, corresponding to one hundred centimeters of soil moisture tension. Option C covers a higher pF range typical of field capacity and plant-available water storage.
- Subject
- Agriculture
- Category
- Agriculture
- Topic
- —
- Difficulty
- medium
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