Water Management
Irrigation methods (surface, drip, sprinkler), water use efficiency, drainage systems, watershed management, water harvesting structures, command area development — high-scoring topic for all agriculture exams.
Frequently Asked Questions
What is the water use efficiency of drip, sprinkler, and surface irrigation?
Drip (micro) irrigation: 90% efficiency — water is delivered directly to the root zone, minimising evaporation and runoff. Sprinkler irrigation: 75% efficiency — water is distributed as artificial rain; some evaporation loss occurs. Surface irrigation (flood/furrow/border): 40–50% efficiency — significant losses from runoff and deep percolation. Drip irrigation is therefore recommended for horticultural crops, sugarcane, and orchards under PMKSY.
What is the IW/CPE ratio and how is it used for irrigation scheduling?
IW/CPE (Irrigation Water to Cumulative Pan Evaporation) ratio is a practical scheduling tool. When the ratio reaches a threshold value (crop-specific), irrigation is applied. For example, wheat irrigation is triggered at IW/CPE = 0.75–1.0. A lower ratio means more frequent, smaller irrigations; a higher ratio means less frequent, larger applications. It integrates weather and crop water demand without measuring soil moisture directly.
What are the critical crop stages for irrigation in paddy, wheat, and maize?
Paddy critical stages: tillering, panicle initiation, flowering, and grain filling — a water deficit at any of these causes significant yield loss. Wheat critical stages: CRI (Crown Root Initiation at ~20 DAS), tillering, jointing, boot, flowering, and grain filling — CRI is the single most critical stage. Maize critical stages: tasseling and silking (50% yield loss from a 7-day deficit at silking).
What are PMKSY and IWMP and how do they relate to watershed development?
PMKSY (Pradhan Mantri Krishi Sinchayee Yojana) was launched in 2015 to achieve 'Har Khet Ko Pani' (water to every field) and 'More Crop Per Drop' — it consolidates AIBP, IWMP, and OFWM into one scheme. IWMP (Integrated Watershed Management Programme) is the watershed development component focused on treating degraded lands through soil and water conservation structures, increasing groundwater recharge, and reducing runoff.
What is the difference between delta, duty, and base period in irrigation?
Delta (Δ) is the total depth of water (in metres) applied to a crop throughout its growing season. Duty (D) is the area (in ha) that one cumec (1 m³/s) of water can irrigate throughout the base period. Base period (B) is the total duration (in days) from first to last irrigation of a crop. Relationship: Δ = 8.64 × B / D.
Which exams test Water Management most heavily?
Water Management is a high-scoring topic in IBPS AFO (Professional Knowledge), NABARD Grade A/B, ICAR JRF (Agronomy/Soil Science), and state PSC Agriculture Officer exams. Drip efficiency figures, IW/CPE scheduling, and scheme names (PMKSY, IWMP) appear as direct MCQs in every major exam.