Irrigation Engineering >> Drip Irrigation System

Drip irrigation, also known as trickle irrigation or micro-irrigation system works in such a way that water is delivered drop by drop at or near the root zone of plants. A network of  valves, pipes, tubing, and emitters is required to develop drip irrigation system. This method is considered as the most water-efficient method of irrigation, since evaporation and runoff are minimized. To make it more efficient it is sometimes buried under the soil (in case of hard soil) at the root-zone level to avoid lose due to evaporation.

Sometimes drip irrigation is combined with plastic mulch, which further reduces evaporation. Drip irrigation requires usually lower water pressures as compared to most other types of systems.

The advantages of drip irrigation are listed below:

• Highly water-efficient.
• Sloping/grading of the field is not necessary.
• reduced leaching which results in minimized fertilizer/nutrient loss.
• irregular shaped fields can also be irrigated
• recycled water can also be used safely.
• maintenance of moisture within the root zone.
• frequency of irrigation is not dependent of soil type.
• Minimized soil erosion.
• Highly uniform distribution of water.
• Lower cost of labour.
• supply can be regulated by valves and drippers.
• possibility of Fertigation with minimal waste of fertilizers.
• reduced risk of disease as Foliage remains dry.
• reduced cost of energy due to lower pressure than other types of irrigation systems.

The disadvantages of drip irrigation are listed below:

• Initial cost can be more than overhead systems.
• The sun can affect the tubes used for drip irrigation, shortening their usable life. Longevity is variable.
• If the water is not properly filtered and the equipment not properly maintained, it can result in clogging.
• Drip irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler irrigation for activation.
• Drip tape causes extra cleanup costs after harvest.
• These systems requires careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components.
• In lighter soils subsurface drip may be unable to wet the soil surface for germination. Requires careful consideration of the installation depth.
• Without sufficient leaching, salts applied with the irrigation water may build up in the root zone, usually at the edge of the wetting pattern.

Other irrigation methods are given below

 surface irrigation  

 sprinkler irrigation  

 sub-irrigation