Drip irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface. The goal is to place water directly into the root zone and minimize evaporation. Drip irrigation systems distribute water through a network of valves, pipes, tubing, and emitters that call Components of the Drip Irrigation System. Depending on how well designed, installed, maintained, and operated it is, a drip irrigation system can be more efficient than other types of irrigation systems, such as surface irrigation or sprinkler irrigation


Components of Drip irrigation

A drip irrigation system consists of the following main components:

  • ·         Head Control Unit

o   Pumping Unit

o   Filtration System

§  Primary Filters

§  Secondary Filters

o   Fertigation System

§  Fertilizer tank

§  Ventury Injector

§  Fertilizer injection pump

o   Safety and Monitoring Devices

§ Non-Return Valve

§  Pressure Release Valve

§  Air Release Valve

§  Pressure Gauges

§  Flow Meter

  • ·         Pipe Network and Fittings

o   Mainline

o   Sub Mainline

o   Lateral

o   Control Valve

  • ·         Emitting System

o   Drippers


The function of Components of Drip irrigation

1_Pumping Units


1.1_Centrifugal Pump

A centrifugal pump is a mechanical device designed to move water by means of the transfer of rotational energy from one or more driven rotors, called impellers. Water enters the rapidly rotating impeller along its axis and is cast out by centrifugal force along its circumference through the impeller's vane tips.

Canal or stored water pump through a centrifugal pump and operate the drip and sprinkler irrigation system.

1.2_Submersible Pump

A submersible pump operates beneath the ground surface. A Submersible Water Pump pushes water to the surface and operates the high-efficiency irrigation system.

 

2_Filtration system

It is the major part of drip irrigation. A filtration unit cleans the suspended impurities in the irrigation water so as to prevent clogging and passage of drip nozzles. The type of filtration needed depends on the water quality used and the emitter type.

 

2.1_Hydro-cyclone

This type of filter used groundwater which is directly pumped, it contains sand particles. The tangential flow of water into the filter creates centrifugal action. Heavier particles (sand) are thrown towards the periphery resulting in their separation from water. These particles accumulate at the bottom and remove through a control valve.

 

2.2_Sand Media/Gravel

These filters are effective against biological substances, inorganic suspended solids, and other organic materials. These type of filter are essential for the open reservoir when algae growth take place and canal water. The impurities are stopped and accumulated inside the media in the filter. A gravel filter consists of small basalt gravel or sand placed in a cylindrical tank, made of metal. Water enters from the top and flows through the gravel while leaving the impurities in the filter and clean water is discharged at the bottom. Cleaning of filter done by reversing the direction of flow. Pressure gauges are fitted at the inlet and cutlet of the filter for monitoring the pressure. There are different sizes of filters available in the market.

 

2.3_Disc Filter

Disc filter consists of grooved plastic discs, which are loaded together around a telescopic core, acceding to the desired degree of filtration. Both sides of the discs are grooved and the grooves cross each other when piled up and frightened together. The housing of the filter is made of plastic or metal and is available in many different sizes. The water passes through the filter from the outside to the inside. It is used after the primary filtration system to filter impurities that pass through primary filters and fertilizer tanks.

 

 

3_Fertigation System

It is used to add chemical irrigation water or dissolved fertilizer; however, fertigation is not free of hazards. Fertilizers or Chemicals added to water may be toxic to humans begins and animals so, safeguards must be taken to prevent the backflow of irrigation water into the water source, which might be used for drinking purposes. Only water-soluble fertilizers should be used to minimize the clogging hazard.

Following equipment used for fertigation

  • o    Venturi Injector
  • o    Injector Pump
  • o    Fertilizer Tant 


4_Pipe Network and Fittings

4.1_Main Line

The main line conveys the water from the head control unit to the sub mains through control valves. They are normally made of uPVC pipes or HDPE in order to minimize corrosion and clogging. Usually, they have placed below the ground i.e. 2 to 3 ft , so that they will not interrupt cultivation practices. Their diameter is based on the system flow capacity. The velocity of flow in mains must not be greater than 1.5 m/s and the frictional head loss should be less than 5ml /1000 m running length of the pipeline.

 

4.2_Sub Main Line

The Sub main carries the water from the mainline to the laterals. They are also buried in the ground below 2 to 3 ft and made of uPVC and HDPE. The diameter and size of Sub main is usually smaller than the main line. There may be a number of Sub main from one mainline depending upon the plot size and crop type.

 

4.3_Control Valve

These are used to control the flow through particular pipes. Generally, they are installed on the filtration system, Fertigation, mainline to Sub main. They are made up of gunmetal, and PVC cast iron, and their size range from ½” to more than 6”.

 

4.4_Flush Valve:

It is used at the end of each sub-main to flush out the water and mud.

 

4.5_Air Release Valve

It is used at the highest point in the main line to release the entrapped air bubbles during the start of the system and to break the vacuum during shut-off. It is also used on the head unit and Sub main if Sub main length is more.

 

4.6_Non Return Valve:

It is controlled backflow and prevents damage to the pump from the flow of water hammer in the rising main line.

 

4.7_Pressure Gauge:

It is provide to indicate the operating pressure of the drip system.

 

4.8_Gromate and Take-off

These are provided to connect the lateral to Sub main. A hole is punched with a hand drill of a predetermined size in Sub main. Gromate is fixed into the hole. Take off is pressed into the hole. Take off is pressed into the gromate with the taking of punch up to the step provided. Gromate acts as a seal. The sizes are different for 12 mm, 16mm, and 20 mm lateral.

 

4.9_End Caps (End Sets)

They are provided to close the lateral ends, Sub main ends, or mainline ends. Sub mains and mains are preferably provided with a flush valve. They are convenient for flushing the line.

 

4.10_Lateral / Poly Tube

Laterals are small diameter flexible tubing or pipes made of liner low-density polyethylene (LLDPE) or low-density polyethylene (LDP) and of 12 mm, 16mm, and 20 mm size. Their color is black to prevent algae growth and the effect of ultraviolet radiation. They are coupled to Sub main at a predetermined distance. The pressure variation between two extreme points lateral should not be more than 15-20 % and discharge variation should not be more than 10%. On sloping ground, the laterals are placed along the contour with 1% extra length for sagging purposes. It may be pressure compensation or non-pressure compensating.

 

5_Emitters or Drippers:

It is the major component of the drip irrigation system for discharging water from the lateral to the root zone of the plant. There are various types and sizes of drippers, based on different operating pressure and flow. They are made of plastic, such as polyethylene or polypropylene. Their discharge range is between 2-40 lph. Each dripper has its own characteristics, advantages, and disadvantages that determine its use.