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.
UNMATCHED
UNIFORMITY
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
|
Pivot 2 |
Pivot 7 |
Area |
129.84 acres( 52.5 ha) |
125.82 acres( 50.9 ha) |
Pivot Manufacturer |
Raincat |
Raincat |
Machine Flow |
900 gpm( 56.8 l / s) |
800 gpm( 50.5 l / s) |
Pivot Pressure |
40 psi( 2.76 bar) |
40 psi( 2.76 bar) |
Machine Length |
1342 ft( 409 m) |
1321 ft( 402.6 m) |
Distance to Last Tower |
1282 ft( 390.7 m) |
1261 ft( 384.3 m) |
Speed of Last Tower |
12.51 ft( 3.81 m) |
12.51 ft( 3.81 m) |
Precipitation / Acre |
6.93 gpm( 0.43 l / s) |
6.36 gpm( 0.43 l / s) |
Time for Coverage |
10.73 hrs |
10.56 hrs |
Soil |
Silt clay loam |
Heavy silt clay loam |
Elevation Change |
17 ft( 5.1 m) |
6 ft( 1.8 m) |
Crop |
Alfalfa |
Alfalfa |
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
AGRICULTURAL IRRIGATION | A Hunter Industries Company Learn more. Visit senninger. com