Drip Irrigation

What is drip irrigation?

Drip irrigation is a micro-irrigation technique of applying irrigation water directly to the soil around the root zone of plants.  

It is the most appropriate method of applying irrigation water to vegetables and fruit crops. 

With drip irrigation the water is precisely applied near the plant roots through a network of drip lines -the pipes fitted with drippers (also called emitters).

What are the advantages of drip irrigation?

Less water requirement

Drip irrigation use 50 to 70 percent less water than conventional irrigation methods and hence more area can be irrigated with same amount of water.

It is more efficient than sprinkler system as it uses 20 to 50 percent less water than sprinkler system.

The water use efficiency with drip irrigation is around 90% whereas as compared to 50 to 70% with sprinkler system.

The high water use efficiency of drip irrigation is due to (1) the water soaking into the soil before it can evaporate or run off, and (2) application of water only where it is needed (root zone of the crop) rather than over the entire field.

Fertigation

Application of fertilizers with irrigation water is called Fertigation. 

Drip irrigation enables farmers to apply fertilizers more efficiently throughout the crop growth period.

Precise application of fertilizers is possible using drip irrigation. Hence, fertilizer costs and loss of applied fertilizers are reduced with drip irrigation.

The slow and steady application of water and nutrients directly to the plant's roots promotes healthy plant growth

Reduce weed growth

By applying water to the root zone of the crop only rather than flooding the entire field reduces weed growth.

Simplicity

Drip-irrigation can be automated with simple devices, and thereby reduce labor cost.

Drip systems are adaptable to oddly shaped fields or those with uneven topography or soil texture.

Drip irrigation operates at low pressures (8–10 psi at the drip line) and farmers may use variable water source. 

Increases production and profit

Applying water with drip irrigation through out the season crop yield and profit.

Farmers should start with drip irrigation with a relatively simple system on a small acreage before moving to a larger system.

Is drip irrigation considered a Best Practice?

Yes.

A Best Practice (BP) is a set of practices known to increase resource use efficiency, productivity and profit, reduce environmental impact and enables climate change adaptation.

Components of a drip-irrigation system

Distribution system

It includes the conveyance of water from the source to the farm and distribution within the farm.

Drip tube

The drip-irrigation system delivers water to each plant through a polyethylene tube called drip lines with regularly spaced small holes, called emitters or drippers.

Plant Nutrients Injector

Injector releases the plant nutrients into the irrigation system.

The most common injector used with drip-irrigation is called Venturi.

Filter

Water filter is essential part of drip-irrigation to clean the source water. 

Because drip-irrigation water must pass through the emitters, the size of the particles present in the water must be smaller than the size of the emitter to prevent clogging.

Screen filter is generally used for spring water.  A 200-mesh screen or equivalent is considered adequate for drip irrigation.

When the water contains sand, a sand separator should be used.

A drip-irrigation system should never be operated without a filter

Pressure regulator

Pressure regulator regulates water pressure at a given water flow.  It helps to protect system components against damaging surges in water pressure.

Pressure gauges

Pressure gauge monitor water pressure in the system and ensure operating pressure remains close to the recommended or benchmark values.

Design and Layout

A drip irrigation system should be able to supply 110% - 120% of crop water needs. In other words, the system should be slightly oversized.

In hills, because differences in altitudes affect water pressure, the drip lines must be parallel to contour lines.

The laterals are network of pipes in the field to which drip lines with drippers or emitters are connected.  For uniform and even water application the network of laterals and drip lines must be appropriately designed.