In May 2018, growers in the Nebraska Panhandle dealt with extensive damage when 80- to 90-mph straight-line winds swept through the region. In their wake, these winds left center pivots upended and sheds and grain bins torn apart, all within a half-hour timespan.
Nicholas Lapaseotes, who farms with his dad, Nick, near Bridgeport, vividly remembers the day.
"We lost 21 pivots, including the two brand-new ones that had LEPA systems installed on them, that had never had water run through them,” Nicholas says. “The straight-line winds blew them over.”
The Lapaseoteses have used Low Energy Precision Application systems since 2014, when they installed their first system on a center pivot.
Between then and 2018, they added three more LEPA systems — including two just before the storm hit in May that hadn't had a chance to make a full revolution yet.
"We had to replace all of those pivots,” Lapaseotes says. “We figured, if we were going to do it, we should look into what fields would be good candidates for LEPA based on the topography and soil type and in places where we're under stricter water allocations. We decide to replace three that weren't LEPA systems before. Most of these are on fields with sandier soils."
What makes LEPA systems different from a standard center pivot setup? Most notably, drop nozzles are spaced closer together (usually 30 or 40 inches apart) and hang 24 to 30 inches off the ground, compared to a normal drop nozzle setup hanging 6.5 or 7 feet in the air. The idea behind the lower-hanging nozzles is to prevent evaporative losses to wind.
WATER SAVINGS: In this 2016 photo, Nick (left) and Nicholas Lapaseotes stand next to the first center pivot they equipped with a LEPA system. The Lapaseoteses have found the soil beneath the crop canopy tends to stay more consistently saturated under LEPA than with normal drop nozzle setups — and in some cases this has resulted in a water savings of 1.5 inches over an entire irrigation season.
Installing a LEPA system
With that in mind, there are a few considerations when determining a candidate field for a LEPA system. Most notably, it's best to install them on a field that's relatively flat.
"The field might look perfectly flat, then you see the pivot running, and a dozen of those drops are dragging on the ground," Lapaseotes says. "When the pivot gets to that hot spot, find the nozzles you need to trim and trim them up a foot off the ground so they're not touching."
It's also important to watch for obstacles in the field that the hose might get caught on. While Lapaseotes notes taller crops such as corn haven't posed a problem for them, obstacles such as fences or structures surrounding irrigation pumps and wellheads can snag nozzles.
"If your well sits on the inside of the circle, or if there's anything in the field that the sprinkler goes over, you will need to walk the pivot over to it, and trim those drops so they don't catch anything," Lapaseotes says. "Sometimes, clamps on the nozzles don't get completely tightened, and the pressure coming out of the gooseneck will blow the hose off. That's usually something you'll see the first couple times you run the pivot around — it's not going to happen when the corn is 6 feet tall."
Of course, with more nozzles spaced closer together, the pipe and setup for a LEPA system is completely different from a standard drop nozzle system.
"The way that most of our LEPA systems are set up, from the pivot point to the first tower, the drops are about 210 inches apart," Lapaseotes says. “They're hung at the same height as a normal pivot setup. When you get to the second, third and fourth towers, you have the long blue drops hanging 30 inches off the ground, but they're 60 inches apart instead of 210. The drops on the fifth and sixth tower all the way to the overhang are all 30 inches apart. So, the pipe you order is going to be different, because you need all those different outlets for the goosenecks."
It's possible to order pipe with enough outlets for LEPA and use it for regular drop nozzles spaced farther apart by plugging the additional outlets. When it comes time to install a LEPA system, simply add goosenecks and longer drop nozzles. However, different pipe configurations have different outlet spacings, including 30-, 40- and 60-inch spacings, and it's also a good idea to consult your irrigation dealer to order the pipe configured for the nozzle spacing that suits your field and soils.
On that note, LEPA systems are best suited to fields with sandier soils — such as the Valentine sands that dominate most of the fields where the Lapaseoteses use LEPA. Running a LEPA on heavier-textured soil can be done, but it's even more important to closely watch soil moisture levels, as having nozzles hanging so closely to the ground means there's greater potential for soils to get saturated faster.
Efficient water use
The Lapaseoteses have found the soil beneath the crop canopy — whether corn or sugarbeets — tends to stay more consistently saturated under LEPA than with normal drop nozzle setups. And Nicholas notes in some cases this has resulted in a water savings of 1.5 inches over an entire irrigation season.
"I've noticed that if I run two pivots side-by-side, one with a LEPA, one without, if they're both the same corn hybrid and planted at the same time, and the pivots are running at the same rate, when I check the field two days later, the one with the LEPA system will be much more saturated, compared to the non-LEPA system," he says. "You're not losing nearly as much water due to evaporation. With long drops you're getting the water right down to the root. You can effectively run the pivots less often and get the same results, so you're ultimately saving water throughout the year."