Adaptability

Sprinklers are available in a wide range of characteristics and capacities and are suitable for most crops and adaptable to most irrigable soils. Set systems can apply water at any selected rate down to 3 mmh-1. This extends the use of sprinkling to fine-textured soils with low infiltration rates. High-application-rate systems, such as the center-pivot and traveling rainguns, are not applicable to low-infiltration-rate conditions. Care is required to select the proper sprinklers for the existing conditions.

Periodic-move systems can be used where the crop-soil-climate conditions do not require irrigations more than every 5 to 7 days and the crop is not too tall or delicate. Where shallow-rooted crops are grown on soils with low water-holding capacities, light, frequent irrigations are required and fixed (solid set) or continuously moving systems are more suitable. Fixed systems also can be designed and operated for frost and freeze protection, blossom delay, and crop cooling.

Sprinklers can be adapted to most climatic conditions, but high wind conditions decrease distribution uniformity and increase evaporation losses, especially when combined with high temperatures and low air humidities. Although sprinkling is adaptable to most topographic conditions, large elevation differences result in nonuniform application unless pressure regulation devices are used. Other aspects relative to adaptability and suitability of sprinkler irrigation and its advantages and limitations are given in the literature [11, 84].

Advantages

Sprinkler irrigation has the following advantages compared to surface irrigation:

• Properly designed and operated sprinkler irrigation systems can give high seasonal irrigation efficiencies and save water.

• Sprinkler irrigation performance is not dependent on soil infiltration (as long as application rate does not exceed infiltration rate), and thus is dependable and predictable.

• Soils with variable textures and profiles can be efficiently irrigated.

• Land leveling is not required; shallow soils that cannot be graded for surface irrigation without detrimental results can be irrigated.

• Steep and rolling topography can be irrigated without producing runoff or erosion.

• Light, frequent irrigations, such as for germination of a crop, can be given.

• Sprinkler systems can effectively use small, continuous streams of water, such as from springs and small-tube or dug wells.

• Mechanized sprinkler systems require very little labor and are relatively simple to manage.

• Fixed sprinkler systems require very little field labor during the irrigation season and may be fully automated.

• Periodic-move sprinkler systems require only unskilled labor; irrigation management decisions are made by the manager.

• Fixed sprinkler systems can be used to control weather extremes by increasing air humidity, cooling the crop, and reducing freeze damage.

• Sprinklers can be managed to supplement rainfall.

• Sprinklers can leach salts from saline soils more effectively than surface or microirrigation methods.

• Cultural practices such as conservation tillage and residue management can be used easily under sprinkler irrigation.

Limitations

Sprinkler irrigation has the following limitations:

• Initial costs are higher than for surface irrigation systems unless extensive land grading costs are required.

• Energy costs for pressurizing water is a significant expense, depending on the pressure requirements of sprinklers used and power costs.

• When water is not continuously available at a sufficient, constant rate, the use of a storage reservoir is required.

• Soil infiltration rate of less than 3-5 mm h-1 will constrain system selection and operating procedures and may result in runoff; center pivots require initial infiltration rates above 20 mmh-1.

• Windy and dry conditions cause water loss by evaporation and wind drift.

• Irregular field shapes are more expensive and less convenient, especially for mechanized sprinkler systems.

• Certain waters are corrosive to the metal pipes used in mainline and laterals.

• Water containing trash or sand must be cleaned to avoid clogging and nozzle wear.

• Sprinkler irrigation water containing salts may cause problems because salts drying on the leaves affect some crops. High concentrations of bicarbonates in irrigation water may affect the quality of fruits. Sodium or chloride concentration in the irrigation water exceeding 70 or 105 parts per million (ppm), respectively, may injure some fruit crops.

• The high humidity and wet foliage created by sprinkling is conducive to some fungal and mold diseases.

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