who had a long career as an extension agricultural engineer with the Texas A&M AgriLife Extension Service. New took the research concept and worked to make it a viable commercial system, leading to the development of the first commercial LEPA water applicator. Over the course of his career, New conducted hundreds of on- farm, side-by-side demonstrations of close drop spacing and LEPA versus conventional water application. These demonstrations confirmed the research findings and lead to the widespread adoption of the system in the Texas High Plains.
My involvement with close drop spacing began in 1990, with the first on-farm evaluation of LEPA off the Texas High Plains. These were conducted in the Winter Garden area of Texas (south and west of San Antonio), where conditions are quite different from the High Plains. The wells yield large volumes of water, and growers can irrigate on demand. Sandy soils reduced the concerns about runoff, and furrow diking and planting in a circle are seen as a disadvantage, particularly when tropical systems dumped large rainfall events on the region. It was from these on-farm evaluations that the LESA [low elevation spray application] concept arose. Water was still discharged near the soil surface, and drop spacing was equal to every other row spacing. Simpler water applicators could be used, with operating pressures as low as 10 psi. Since 1980, I’ve conducted numerous on-farm comparisons of LESA versus over-canopy irrigation, often with dramatic results.
Guy Fipps, PhD, PE, is a
professor and extension agricultural engineer at Texas A&M. Specializing in irrigation technology, water quality and water management, Dr. Fipps
has devoted over 25 years to
improving irrigation efficiency, developing new technologies and promoting managing water use more efficiently. His accomplishments are numerous, including begin chosen as the IA’s
Person of the Year in 2015 and the ASABE Professional Engineer of the Year in 2014.
LEPAcase studies Alfalfa
The following two case studies provide information from growers in Nevada and Kansas outlining their experiences using LEPA systems on alfalfa and corn.
Triple D Ranch is in the high valley of Dyer, Nevada. The climate is windy with little to no rainfall and very low humidity. Declining water tables, increasing pumping costs, as well as wind and evaporation loss led John Maurer, the farm manager, to investigate ways to reduce water use and still retain successful yield levels.
Mauer read an article about close spacing LEPA in a farming magazine. Then, seeing those actual products displayed at a farm show prompted more in-depth research. Securing and testing product samples, they selected a sprinkler with a shroud and a LEPA bubble insert. They kept traditional sprinklers on the first two spans and switched to LEPA bubblers on the outer spans at about 8 – 16 inches off the ground.
“With the windy conditions in the valley, it was evident that the LEPA bubblers were simply not misting like traditional sprinkler systems. Water typically lost to evaporation and wind drift was saved,” Maurer said. Probes validated water was penetrating deeper to the root zone. When checking the yield beneath the LEPA bubblers, Maurer saw an increase in production and decided to expand this type of installation converting as many machines as possible, even between cuttings.
Corn
Bob Holloway’s farm is in a low gallonage area of Kansas, south of Colby and west of Mingo. He irrigates with well water fed from the Ogallala Aquifer. Due to water availability, most farms in this area are only able to farm in half fields — growing half circles of wheat and corn — on a 120-acre field.
Holloway’s dealer in Colby, Kansas, helped him modify his irrigation installation
converting to close spacing sprinklers with shrouds and bubbler pads. With a field slope of about 0.5 percent, he mounted the bubblers at about 8 – 18 inches off the ground. “I found that the LEPA bubbler system allowed us to apply the water we have available in a more productive way. The water that is being applied is resulting in less wind drift and more subsoil moisture.”
LEPA bubbler ys e bb er systemon oron co n soutso th off Colbyo by, Kansas ansa
Recognizing there are various factors impacting the season- end yield results on a farm, Holloway feels the change to his irrigation setup has contributed to the success he is seeing. He has been able to farm 50 percent more corn (a total of 120 acres) with just 250 – 300 gpm.
Photo credit: Senninger
irrigationtoday.org 15
Clos
C o e spa n on
pacing on alffa aalfa in Dyer Neva
ye , N vada
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