In-ground irrigation

A variety of sprinkler heads for in-ground irrigation systems are on the market ranging from large impact driven sprinklers (Fig. 1) to the smaller spray sprinklers (Fig. 2).

Spray pattern and uniformity of water distribution are two important factors.

In-ground sprinkler systems are more expensive than portable systems, but they are more convenient to use. These systems may be controlled manually or electronically. Irrigation systems can be designed with rain sensors to shut off the irrigation in the event of rain. Others use tensiometers (devices which measure soil moisture) to determine when to water.

There are also many different hose-end sprinklers available.

• Figure 3 illustrates an impulse sprinkler
• Figure 4 illustrates an oscillator sprinkler
• Figure 5 illustrates a salt-shaker sprinkler

One major drawback of using sprinklers is that they lose water to the atmosphere through evaporation. However, they are often the only practical option for irrigating turf grass and some types of ground covers. Water loss can be reduced by practicing efficient watering techniques.

Drip irrigation

Drip irrigation systems use frequent applications of water to a small area of the root zone.

The main benefit of low volume systems is little or no water loss due to evaporation. These systems also prevent watering of sidewalks, patios, and other areas that do not require water.

By using these systems, water use can be cut by as much as 20 to 50 percent.

Types of drip irrigation

The water is delivered, at a very slow rate, through either drip emitters, porous pipes or soil soakers.

Porous Pipes

Porous pipes are made of a plastic material that leaks water continuously over its entire surface. They can be attached to the garden hose or a stationary irrigation system. They can be used above ground or under a mulch layer.

Evaporation is limited because the water is not sprayed into the air. When surface applied, the hose can be placed under shrubs and other shady areas to reduce evaporation. Porous pipes are good for applying water to long rows of closely spaced plants.

Soil Soakers

A soil soaker is a long hose that has many tiny holes in it. Generally, soil soakers are portable and attach to the garden hose. A soil soaker produces a fine mist that is good for watering larger areas. The hose may be used to make a surface application, or it may be used under a mulch. Because of the fine mist, evaporation can be a problem when soil soakers are used on the surface.

Advantages of using drip irrigation systems

1. Water is concentrated where it can be most useful to the plants.
2. Weeds are minimized.
3. Disease is minimized due to reduced wetting of the foliage.
4. Liquid fertilizer can be added to the water.
5. Is good for trees, vines, shrubs.

1. Breakdowns are not obvious until plants begin to wilt.
2. The smaller lines are prone to clogging. Filters and periodic flushing is required.
3. Salt buildup may be a problem in some soils.
4. Insects and rodents can damage the plastic lines.
5. It is not good for solid masses of plants without distinct root zones such as turf grass and ground covers.

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