Published on October 13, 2016 10:30AM
MUD LAKE, Idaho — Growers on the Eastern Snake River Plain will remember 2016 as the year a tight water supply got even tighter.
Many were forced to reduce the amount of water they use for their crops, enter costly leases to offset their impact on a declining aquifer — or leave some of their land fallow.
But a few farmers, including Steve Shively, say they have found a way to stretch their water supply without sacrificing their crops.
The Mud Lake, Idaho, grower is a pioneer in the use of low elevation sprinkler application, known by the acronym LESA. It’s an irrigation method developed by University of Idaho and Washington State University researchers specifically for the Pacific Northwest.
Under the terms of a monumental 2015 water call settlement with senior surface water coalition members, irrigators who pump groundwater from the aquifer must reduce their water consumption by a total of 240,000 acre-feet per year.
One acre-foot covers an acre of land with water 1 foot deep — about 325,850 gallons of water.
For them, the massive settlement translates into a cutback in irrigation water by an average of 12 percent for every groundwater irrigator in the region. The exact amount varies by the farmer’s groundwater right priority dates.
At a time of basement-level commodity prices, the settlement was a potential double-whammy for many farmers: Less irrigation water would mean lower yields for crops that were bringing lower prices.
Shively, however, said switching to the LESA irrigation method has simultaneously saved water and boosted his farm’s yields.
“Our farm is required to reduce by 7 percent, and we feel like we can easily save 25 percent,” Shively said. “We are not worried about making our water savings on this settlement, while at the same time, we’re seeing as good or better yields than we were previously.”
How it works
The heart of the system is low-pressure nozzles that dangle from long hoses attached to the pivot. The hoses are 54 inches apart instead of the standard 108 inches.
Spraying just 12 to 18 inches from the ground provides ample water coverage while reducing drift and evaporation, especially once the crop canopy grows enough to contain the spray.
Shively first tested LESA on a single pivot span over alfalfa last season.
During Shively’s trial year, second-cutting alfalfa under the LESA span yielded three-quarters of a ton per acre more than the conventional pivot setup.
Furthermore, soil remained moist more than 5 feet deep under the LESA span, compared with just 18 inches for the conventional irrigation setup.
Shively also believes LESA, which doesn’t moisten the crowns of grain, has kept stripe rust in check and prevented water weight from tipping stalks.
This season, Shively converted four full pivots to LESA. The results have far exceeded his expectations.
He planted two pivots — one conventional and one using LESA — a day apart and under identical conditions, using the soft white spring wheat variety WB 6430.
The LESA pivot used about 4 inches less water but yielded about 115 bushels per acre, compared with 75 bushels per acre under the conventional pivot.
“The pivot without LESA, we struggled to keep it wet,” Shively said. “We couldn’t turn the pivot off.”
In another field, Shively planted hard red winter wheat and used a LESA setup. It yielded 125 bushels per acre and used 10.5 inches of water.
In 2014 using a conventional pivot, the same field yielded 10 fewer bushels per acre but needed 8 more inches of water per acre.
Growers throughout the region are starting to follow Shively’s lead.
The Idaho Falls office of the USDA Natural Resources Conservation Service has awarded $300,000 through its Environmental Quality Incentives Program to help area growers install 32 new LESA systems for use next season, many near Mud Lake.
NRCS District Conservationist Josh Miller said the agency received applications to convert 60 pivots and hopes to obtain funding for an additional sign-up in November.
Miller said the grant, conducted in partnership with Rocky Mountain Power, pays up to $7,000 to convert a single pivot and is capped at $12,000 per applicant.
The sales staff at Golden West Irrigation in Rexburg, which has seen strong LESA sales this fall, estimates the cost of outfitting a pivot with LESA at $10,000 counting labor.
However, most growers, including Shively, opt to install LESA when their conventional pivot nozzles and fittings are worn, and updating a pivot with conventional equipment still costs up to $3,500, counting labor.
Grant recipients are required to use soil-moisture sensors in conjunction with LESA to avoid over-watering crops.
“With the groundwater issue, I think there are a lot of people interested in using these systems to meet those cutbacks,” Miller said.
To meet his reduction, one of the grant recipients, Lane Hutchings of Monteview, Idaho, has already dried 50 acres he’d been irrigating with labor-intensive handlines and a portable mainline.
While meeting with an irrigation equipment salesman about purchasing his first LESA package, the malt barley and alfalfa grower said he’s optimistic LESA will provide a painless way for him to further reduce his well water consumption.
“I think (LESA) will be on everybody’s pivots here before long,” Hutchings said.
Bonneville Power Administration also offers a grant to help growers convert to LESA, based on the potential power savings.
UI Extension irrigation specialist Howard Neibling and Troy Peters, his WSU counterpart, tested the first LESA pivot spans in Wells, Nev., in 2013, with funding from the BPA.
They sought to tweak a common Texas irrigation method for more arid conditions. Texas-style low elevation precision application uses long hoses to position low-emitting drip nozzles beneath crop canopies. Neibling and Peters chose adjustable nozzles, as they planned to use a spray setting to get crops germinated, before switching to a drip setting.
However, they forgot to tell the grower to adjust the nozzles. Serendipitously, the spray setting provided ideal coverage and moisture penetration, while reducing water use by 15 percent, and modern LESA was born.
The following year, they expanded the LESA trials to a few sites in Idaho and Washington.
“We got a good data set in Arco, Idaho, showing over 20 percent water savings,” Neibling said. “We were saving a remarkable amount of water on hot, windy days — like close to half.”
Anheuser-Busch funded LESA trials on three pivots in Idaho this season to test the technology on malting barley. Growers reported barley plants were less prone to tipping, but the thick barley stands blocked spray. The problem was remedied by reducing the distance between the pivot drops.
Neibling said some potato growers worried LESA nozzles could damage vines or spread diseases, but Arco seed potato farmer Mike Telford reported no problems with LESA.
Joe Jepsen, a Rexburg, Idaho, potato farmer, also experienced no problems in spuds with a LESA trial this season. While some spud growers with lighter soils have complained LESA washes away dirt and exposes tubers to light, Jepsen said his soil was heavy enough to avoid trouble.
“We had a lot of wind this year, and we could definitely see the evaporation loss, and with the LESA system there was not that loss,” Jepsen said, adding that he’ll study LESA for three years before expanding its use on his farm. “I think we can make our (settlement) cutbacks with LESA and still grow a good crop.”
He’s still compiling data on LESA use in spuds and wheat, but he said there was a water savings and spud quality was much improved under LESA.
Neibling believes LESA still needs more testing on hilly terrain and clay soils, and he acknowledges it may be a poor fit for fields that have runoff issues, but he estimates it could be effectively used on about half of Idaho fields.
LESA in California
Last season, University of California crop advisor Steve Orloff tested LESA on spans of three pivots irrigating alfalfa in Northern California’s Siskiyou County. In parts of the region, including the Scott Valley, agricultural water use is under scrutiny due to mounting interest in the interconnection between groundwater and surface water.
Based on the results of his 2015 trials, Orloff said eight commercial alfalfa growers in the region had full pivots of LESA to start this season. He suspects more pivots were converted during the season, and he envisions more LESA systems will be installed as growers replace worn pivot equipment.
He estimates LESA reduced water waste by 15 percent in the California trials, even working well on a sloping field with heavy soil.
“I don’t know of anyone who has been dissatisfied with it,” Orloff said.
Peters, the WSU irrigation researcher, believes LESA has been quickest to catch on in Eastern Idaho due to the settlement, but he said several growers in Eastern Washington and Oregon have experimented with a single span on their pivots.
He said growers have had luck with LESA in mint, corn, potatoes, wheat, barley and alfalfa. Peters explained LESA yield boosts should be expected only in crops that were water stressed under conventional pivots, but he noted the approach can always help growers save on input costs.
“I think it’s a winner technology,” Peters said. “It saves water, it saves energy, it makes it so the grower can be more profitable, and it’s good for the environment.
“I hope more people will take a serious look at it.”