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Sprinkler

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[[File:sprinkler data.jpg]]
 
==Costs==
The total cost for the installation of the system in 2.0 ha (as in the example design) is US$1 790.00, or less than US$1 000/ha. A cost analysis shows that the head control costs about US$70. The major cost items are the plastic pipes, PVC and PE tubes, for the system’s network which amount to
US$1 177, 65.7 percent of the total cost. Imported sophisticated equipment, such as the sprinklers, rarely exceeds 10 percent of the total cost.
 
==Field experiences==
EXAMPLE DESIGN
'''Hose-move sprinkler for cotton'''
 
Area and crop: An area of approximately 2.0 ha planted with cotton at the beginning of August. The field is square and level. Soil, water and climate: Medium texture soil of good structure, with good infiltration and internal drainage. The soil available moisture (Sa) is 110 mm/m depth. The water is of good quality with no salinity or toxicity hazards; the source is a tube-well equipped with a pumping unit delivering 36 m3/h. The peak irrigation demand is in October, at the midseason growth stage of the crop.
 
Crop water requirements and irrigation scheduling: The pan average readings in October are 5.6 mm/d. This figure multiplied by 0.66 (pan correction factor) gives an ETo of 3.7 mm/d. The crop factor kc for cotton at this stage is taken as 1.05, the root depth 1.0 m and the moisture depletion 50 percent. Then, ETc cotton = 3.7 x 1.05 = 3.88 mm/d. The net application depth is Sa 110 mm x root depth 1.0 m x depletion 0.5 = 55 mm. The maximum permissible irrigation interval in October is 55 mm ÷ 3.88 mm/d = 14 days. The irrigation frequency depends on many factors and in no case should exceed the maximum permissible irrigation interval. The system’s application efficiency is 75 percent, therefore, the gross application depth at peak is: 55 mm ÷ 0.75 = 73.3 mm. The gross irrigation dose is: 73.3 mm x 10 x 2.0 ha = 1 466 m3.
==Acknowledgements==
* M. Kay and N. Hatcho. [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CGkQFjAA&url=ftp%3A%2F%2Fftp.fao.org%2Fagl%2Faglw%2Ffwm%2FSmallScalePumpedIrrigation.pdf&ei=WyXFT9SKO-r2sQKDuYDoDw&usg=AFQjCNEEHF2n_scI2pDSHzV9R_CWhHk87w&sig2=8_sjoqXSBWPQ41-1s7_iVw Small-scale pumped irrigation energy and costs.] FAO. 1992.
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