The wilting point marks the threshold beyond which crops suffer stress and water becomes unavailable; this point is reached after _________________?
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Answer: C. 20% water available
Explanation
Crops experience severe wilting and moisture stress when available soil moisture falls to 20%. This permanent wilting point marks the critical threshold where plant roots can no longer extract water. Cell turgor pressure collapses, causing irreversible wilting and eventual crop mortality. Soil moisture availability ranges between field capacity and permanent wilting point limits. When available water drops to about twenty percent, soil suction exceeds fifteen atmospheres. Crops must be irrigated before reaching this critical stress threshold to maintain yields.
Agricultural irrigation scheduling relies on monitoring soil moisture to prevent crop stress. Reaching the wilting point drastically reduces photosynthetic activity and destroys harvest potential. Farmers use tensiometers and soil probes to track moisture depletion toward this critical limit. Option A represents a higher moisture level where crops still transpire without severe stress. Option B is an intermediate moisture availability state well above the critical wilting threshold. Option D is incorrect because only the 20% available water option marks the wilting point.
- Subject
- Agriculture
- Category
- Agriculture
- Topic
- —
- Difficulty
- medium
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