If rice requires about 10 cm of water at an average interval of about 10 days and the crop period for rice is 120 days, then the delta for rice will be
- A90 cm
- B100 cm
- C110 cm
- D120 cmCorrect
Solution
Concept
Delta (Δ) of a crop
Formula
Δ = (Number of waterings) × (depth of each watering) = (B / interval) × depth
Step-by-step solution
1. Crop period B = 120 days; watering interval = 10 days. 2. Number of waterings = 120 / 10 = 12. 3. Delta Δ = 12 × 10 cm = 120 cm.
Explanation
Delta is the total depth of water (in cm or m) required by a crop during its entire crop period. Here rice needs 10 cm every 10 days for 120 days, so 12 waterings × 10 cm = 120 cm.
Shortcut
Δ = (crop period ÷ interval) × depth per watering.
Common mistake
Confusing delta with duty. Duty is area irrigated per cumec; delta is a depth of water.
Correct answer: D) 120 cm