RAFT RIVER, Idaho — Farmer Todd Garrett believes water has become a precious enough commodity in southeast Idaho to justify his investment in costly buried drip irrigation at a commercial scale.
On April 15, Garrett finished installing drip lines buried a foot deep and spaced 36 inches apart throughout an 80-acre field. He’ll plant alfalfa this season, but Garrett said the spacing of the drip lines makes drip potato production a future possibility.
He’s seeking solutions to address a water shortage within a designated critical area of the Raft River Aquifer, knowing he could soon be expected to dry 200 acres irrigated by so-called expansion water rights — in which growers who didn’t fully utilize groundwater rights years ago were allowed to add new pivots elsewhere.
In addition to buried drip, he’ll be experimenting this season with a pivot dragging drip tape and Low Elevation Spray Application. LESA, which entails running pivots with low-pressure nozzles dangling about a foot off the ground, was developed by University of Idaho irrigation specialist Howard Neibling and his Washington State University counterpart, Troy Peters.
Garrett will use identical water meters on each system, plus a standard pivot with a new irrigation package as a control, to evaluate which option provides the most per-gallon water savings for the money. Each field has similar soil and will be planted in alfalfa. He’ll host a field day in mid-July, after his second cutting, to share his results.
“I want to see what is going to be the most economical for me, the most user friendly and the most maintenance friendly,” Garrett said. “I wanted to do it in full-scale-production-sized fields so it’s real-world, real-life scenarios.”
Based on prior testing, Garrett said buried drip — which recycles unused water in a closed system — should cut his water use by 40 to 60 percent, compared with 15 to 20 percent with LESA and 20 to 25 percent with drag-drip.
Garrett said buried drip costs about $2,000 per acre to install, and he’ll likely soon expand to 160 acres, which would equal the capacity of his new buried-drip sediment filtration system. He hopes to lease the buried-drip ripper he purchased to other regional growers installing buried drip, or to custom install for them.
Neibling, who will help Garrett evaluate data, explained surface drip systems are widely used in high-value crops, such as mint and onions, in Western Idaho, but buried drip systems are a rarity in the state. In Western Idaho, Neibling said rodents have posed an obstacle to buried drip, and he anticipates LESA and drag-drip will provide Garrett the best return for his investment.
Neibling said all three options should provide ample water savings, but growers will likely adopt “the easiest option to install and manage and the cheapest, particularly because it’s something they’re used to.”
Butte Irrigation, the Israeli drip-irrigation manufacturer Netafim and buried-drip expert Jerry Funck, with Professional Water Management Associates in Lubbock, Texas, are also helping Garrett set up the trials. Garrett traveled to Lubbock to see growers’ water-efficient systems and was impressed that many buried-drip systems were still working well after more than 15 years. He’ll run rodenticide through his drip lines to prevent chewing, and herbicide to keep roots from growing into lines, and he’ll use an additive to avoid calcium deposits. He’ll limit tillage to no deeper than 4 inches.
Funck said his state has about 600,000 acres of buried drip, and they’ve boosted yields while curbing water and power use. He said systems also precisely deliver fertilizer exactly where crops need it.
“I think it’s ripe for drip in Eastern Idaho,” Funck said.