Drip Irrigation System

Micro Irrigation has gained attention during recent years because of its potential to increase yields and decrease water , fertilizer and labour requirements if managed properly.

Principal characteristics distinguishing the micro Irrigation with other pressurized technologies are:

  • Low flow rate
  • Localized , partial wetting of the soil volume
  • Frequent water application due to the limited wetted volume
  • Low operating pressure ,compared to sprinkler irrigation

Drip Irrigation involves technology for irrigating plants at the root zone through emitters fitted on a network of pipes( mains ,sub-mains and laterals). The emitting devices could be drippers ,micro sprinklers, mini sprinklers ,micro jets, misters ,fan jets, micro sprayers, foggers and emitting pipes, which are designed upon specific requirements , which may vary from crop to crop . Water requirement, age of plant spacing ,soil type , water quality and availability are some of the factors which would decide the choice of the emitting system .

In cases where the water sources is an open well or tubewell / borewell , then for assessment of water availability and pumping power requirement it is necessary to compute the following:

  • Depth of the water table
  • Discharge of the well
  • Total pumping level
  1. The depth of water level below the ground level, before pumping begins ,is the depth of the water table . It can be measure by a simple procedure using a rope with a stone tied at one end .
  2. The discharge of the well / tubewell is measured after running the pump for a period of 30 minutes to 1 hour . It can be measure by adopting volumetric measure.Under this method , the discharge is emptied into a ditch of container of know dimensions for a certain length of time . the rate of discharge is calculated by dividing the total volume of water discharged by the time taken. This method works for low discharge say upto 5 litres per second. For higher discharges volumetric measurement may be difficult and therefore standard devices like water meter/c.notch/flume may be used.
  3. Total pumping level includes the depth of the water level, drawdown and height of the outlet above the ground level. To measure the drawdown the pump installed over the well/tubewell is run for a period of 30 minutes to one hour so that constant water level is attained in the well/tubewell. The new depth of the water level is measured. The difference between the depth and level above the ground level is also to be measured . Once the total pumping level is determined , the horsepower .

HP= Q*H/75*n

where Q = Discharge ,Ips

H=Total head ,m

n = Efficiency of the pump and motor

Depending up on the water availability and water requirement of the crop (as given in the table ) for the entire area in calculated .Then the piping network and number of sections will be decided accordingly.

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