2015 to 30 inch ( 76 cm ) spacing between hose drops and 18 inch ( 45.7 cm ) applicator height . The results were water and energy savings .

Background – LEPA Close Spacing Close Spacing is a water-efficient irrigation practice that combines the low-pressure bubbler heads made for LEPA ( Low Energy Precision Application ) with conservation tillage practices . LEPA bubblers operate at low pressures ranging from 6 to 20 psi ( 0.41 to 1.4 bar ). They use less energy than conventional lowpressure sprinklers , and operate using fewer gallons per minute than conventional spray nozzles .

Pivots equipped with LEPA systems deliver water 8 to 18 inches ( 20.3 to 45.7 cm ) above the ground in an effort to combat wind-drift and prevent evaporation loss . When LEPA was initially conceived , sprinklers were placed 60 to 80 inches ( 152.4 to 203.2 cm ) apart to irrigate every other furrow . In contrast , Close Spacing method distributes water over most of the soil surface with 40 inches ( 101.6 cm ) or less between heads . Conservation tillage practices further help prevent evaporation loss , and run-off .

In Depth Testing

In order to learn what was actually contributing to the improved results , Triple D Ranch partnered with Senninger on a new test beginning July 2016 .

Centre pivots – case study

This would include a span to span direct comparison measuring the following : Yield , Water Penetration , Salinity , Soil temperature , Total Water applied , ET . This allowed for a more direct comparison of moving deflector sprinklers with LDN LEPA applicators within the same field reducing the variability of different soil types and plant ages .

Test Description The test was set-up with three spans of moving deflector sprinklers and four spans of LDNs with LEPA pads ( C33 / CM1 ) and Shrouds . XX

Sprinklers were at 120 inch ( 3 metres ) spacing , 36 inch ( 91.4 cm ) height , with 10 psi ( 0.69 bar ) pressure regulators .

XX

LEPA applicators were at close spacing of 30 to 40 inches ( 76 to 101.6 cm ), 18 inch ( 45.7 cm ) height , with 10 psi ( 0.69 bar ) pressure regulators .

XX

Balanced flow rates consistent with their pivot span location .

XX

Two soil moisture probes employed per pivot – one under span with moving deflector sprinklers and one under span with LEPA LDNs .

XX

Pivots tested had similar characteristics . There were slight variations in the soil but the crop was the same seed variety and the field inputs were the same .

SENNINGER SPRINKLERS - PROVEN PERFORMANCE AND RELIABILITY

Rain-like , uniform distribution and an even droplet size large enough to resist wind-drift without disrupting the soil .

i-Wob ® ( Grey )

• Smaller droplets

• For tight soils

• Standard angle

i-Wob ® ( Black )

• Medium droplets

• For most soils

• Standard angle

i-Wob ® ( Blue )

• Medium droplets

• For most soils

• Low angle i-Wob ® ( White )

• Larger droplets

• For sandy soils

• Low angle

Field Inputs Sulfur , Nitrogen , Zinc , Phosphorus

Table 1 . Test Pivot Specifications .

SABI | FEBRUARY / MARCH 2017 13

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