Centre pivots – case study
Soil Water Content ( inches )
Figure 1 . Test Pivot 2 span results for Close Spacing LEPA LDNs .
Figure 2 . Test Pivot 2 span results of sprinklers .
Image 4 . Locations of Pivot 2 ( North ) and Pivot 7 ( Oasis ). Climate Characteristics
XX Mean annual air
XX
Mean annual precipitation : 4 temperature : 50 to 54 ° F to 9 inches ( 10.1 to 22.8 cm ) ( 10 to 12.2 ° C )
XX
Frost-free period : 130 to 155 days
Results
After converting to LEPA irrigation , efficiency was much higher : XX
Less water used : reduction of 152.7 Acre-Feet ( 188352.4 cubic metres ) water applied at control ranch – 8.7 % with LEPA ; reduction of 272.9 Acre - Feet ( 336616.69 cubic metres ); water Applied at all other ranches – 17.8 %
XXWind loss reduced XX
Evaporation loss reduced
XX
Electric costs reduced as consumption went down – 170,811 kWh energy reduction = $ 16,620 USD savings / year
Additional benefits : XXHigher yield production
XX
Savings by reducing varmint damage
Conclusion
Close Spacing irrigation using shrouded LEPA applicators improves irrigation efficiency in this semi-arid climate . Losses to wind drift and evaporation are minimized , which means more water is available for plant use . Low pressure operation saves pumping energy . This application creates an undesirable habitat for field varmints and thereby reduces labor and repair costs . With only two cuttings , the impact on yield is yet inconclusive .
Further research in the 2017 season is needed to adjust the irrigation prescription to reduce the amount of water applied with LEPA LDNs to better determine specific water and energy savings and yield variation .
About John and Dan :
* John Maurer , Manager of Triple D Ranch Twenty-five years farming experience and Central Nevada Regional Water Authority ( CNRWA ) Member , Valley Electric Association District 4 Director and Board President , hillsidehayco @ gmail . com
* Dan Schueler , District Manager for Senninger Irrigation Thirty-nine years in the irrigation industry , Studied at Oklahoma Panhandle State University and Agriculture at Lamar Community College , dan . schueler @ senninger . com
References
• Crop Metrics is managing the soil moisture probes . The login page shows information about the probes . http :// cropmetrics . com . October 18th , 2016 .
• Snyder , A . D . “ Efficiency and uniformity of the LEPA and spray sprinkler methods : A review .” ResearchGate . Transactions of the ASAE , pp . 937-944 , Vol . 43 , No . 4 , July 2000 . www . researchgate . net / publication / 43255576 _ Efficiency _ and _ uniformity _ of _ the _ LEPA _ and _ spray _ sprinkler _ methods _ A _ review . October 18th , 2016 .
• National Resources Conservation Service . United States Department of Agriculture . www . nrcs . usda . gov . October 18th , 2016 .
• Station Monthly Time Series . Western Regional Climate Centre . October 18th , 2016 . www . wrcc . dri . edu / cgi-bin / rawMAIN . pl ? nvdyer . October 18th , 2016 .
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SABI | FEBRUARY / MARCH 2017