What is Irrigation?

Irrigation is the artificial application of water to the land or soil to:

  • Assist in the growing of agricultural crops
  • Prevent soil consolidation
  • Maintain landscapes

Benefits of Irrigation

  • Improved crop quality
  • Effective management of crop water needs
  • Increased crop yields
  • Opportunities for double cropping
  • Means of liquid fertilizer application

Types of Irrigation Systems

Surface Irrigation

In surface irrigation, water moves over and across the land by simple gravity flow in order to wet and infiltrate the soil.  Surface irrigation can be divided into furrow, border strip or basin irrigation.  It is often called flood irrigation when it results in flooding or near-flooding of the cultivated land.

Sprinkler Irrigation

Sprinkler irrigation is another popular method, where a set amount of water is piped to the fields and sprayed directly over the crops with the use of high pressure sprinklers.  The amount of water can be closely controlled, which is a huge benefit.

Drip Irrigation

Drip irrigation, also known as trickle irrigation, functions as its name suggests, where water is delivered at or near the root zone of plants in drops.  This method can be the most water-efficient method of irrigation if managed properly, since evaporation and runoff are minimized.  In modern agriculture, drip irrigation is often combined with plastic mulch – further reducing evaporation.  Drip irrigation is a means of the delivery of fertilizer in process is known as fertigation.

Centre-Pivot Irrigation

Centre-pivot irrigation involves a self-propelled system in which a single pipeline supported by a row of mobile towers is suspended 2 to 4 meters above ground.  Water is pumped into the central pipe and as the towers rotate slowly around the pivot point, a large circular area is irrigated.  Sprinkler nozzles mounted on or suspended from the pipeline distribute water under pressure as the pipeline rotates. The nozzles are graduated small to large, so that the faster moving outer circle receives the same amount of water as the slower moving ones on the inside.

Manual Irrigation

These systems have low requirements for infrastructure and technical equipment but need high labour inputs.  Irrigation using watering cans is  found in most rural areas and peri-urban agriculture around large cities.