2 Drip Irrigation

Components of Drip Irrigation System

  • Definition: Drip irrigation is the precise, slow application of water through emitters or applicators, used synonymously with trickle irrigation.

  • Historical Background:

    • 1940: Symcha Blass observes enhanced growth of trees near leaking faucets.

    • 1964: Develops the first patented drip irrigation system.

    • Rapid adoption in the late 1960s across Australia and the USA.

  • Global Adoption:

    • 1988: Approximately 10,55,000 hectares under drip irrigation worldwide.

    • USA leads in area covered by drip irrigation.

    • India: From 1,500 ha in 1985 to 24,500 ha in 1991, especially effective in water-scarce regions.

Key Components of Drip Irrigation

  1. Pump: Lifts water from the source.

  2. Head Unit: Tank that maintains pressure for circulating water.

  3. Filter: Removes suspended materials from water.

  4. Main Supply Pipe: PVC pipes of suitable diameter for optimal discharge.

  5. Lateral Lines: Distributes water from main supply to sub-main lines.

  6. Drippers: Control the release of water, installed at planned spacing.

  7. Fertilizer Tank: Supplies nutrients mixed with irrigation water.

Water Filtration and Pressure Regulation

  • Sand Filter: Efficiently removes particles from water; back flushing is used for maintenance.

  • Check Valve: Prevents backflow when the pump is shut down.

  • Water Meter: Measures discharge.

Types of Drippers

  • Various emitters including orifice, vortex, and flexible types; aim for compact, cost-effective, and clog-resistant design.

  • Emitter Characteristics:

    • Low discharge rates (2-4 liters/hour).

    • Resistance to clogging.

    • Uniformity in water application.

Irrigation Design Considerations

Key Factors

  • Topography: Land contour affects design.

  • Water Source: Evaluate quality and discharge availability.

  • Crop Type: Different crops have unique irrigation requirements.

  • Soil Type: Assess permeability and infiltration rates.

Drip Irrigation Systems Overview

Common Types

  1. Surface Drip Irrigation: Emitters situated on the soil surface.

  2. Subsurface Drip Irrigation: Emitters buried below the surface.

  3. Pulse Irrigation System: Applies water in intervals.

Experimental Results and Moisture Management

  • Drip irrigation maintains optimal moisture conditions, improving yields and reducing water wastage.

  • Effective in managing soil salinity, allowing for better salt leaching.

System Efficiency and Economic Aspects

  • High application efficiency achieved through precise water delivery.

  • Reduced energy and operational costs compared to traditional systems.

Fertigation

  • Fertigation integrates fertilizer application with irrigation, ensuring uniform nutrient distribution and minimized nutrient loss.

  • Important to select appropriate fertilizers to avoid clogging issues.

Clogging Control Measures

  • Regular maintenance includes flushing filters and checking for clogging from particulates, precipitation, and biological growth.

  • Use of acids and chemical treatments to prevent and manage clogging.

  • Emergency procedures for rapid flushing during operational disturbances.