Irrigation and Water Management: Scheduling, Efficiency and Drainage
Irrigation and Water Management tests scheduling, irrigation methods, efficiency and drainage. Haryana faces both canal rotation and groundwater depletion, so both science and practice matter.
Core rules
- Know field capacity, wilting point and available water. Irrigate before stress crosses the allowable depletion, especially at critical stages.
- Canal warabandi allocates fixed time slots; drip and sprinkler systems raise application efficiency. Laser levelling improves uniformity and saves water.
- Test brackish water before use. Provide drainage where waterlogging or secondary salinity appears.
- Pradhan Mantri Krishi Sinchayee Yojana supports micro-irrigation and water-saving technologies.
Worked example
Root zone = 60 cm, field capacity = 30%, wilting point = 12%, allowable depletion = 50%. Available water = (30 − 12)% × 60 cm = 0.18 × 60 = 10.8 cm. Allowable depletion = 0.50 × 10.8 = 5.4 cm. Apply about 5.4 cm, or 54 mm, of water. If cumulative pan evaporation is 0.6 cm/day, the interval is about 5.4 ÷ 0.6 = 9 days, adjusted for rainfall. The reasoning must keep depth and interval separate.
Traps that cost marks
Do not confuse delta, the total crop water requirement, with duty, the area served per unit of water. Do not irrigate by calendar alone, over-irrigate saline soil, ignore critical stages, or use brackish water without testing. Do not leave channels unlined or assume rain replaces the calculated depth.