A low-tech, easy-to-install-and-maintain irrigation system is giving U.S. grazing dairies a new tool to ensure pastures remain productive through summer slumps.
Steve Guell, Waupun, WI, installed a K-Line Irrigation system, developed in New Zealand, in a 54-acre pasture in the fall of 2005.
“Summer slump was really becoming a problem for us,” says Guell, who grazed 32 registered Jersey cows, 25 Jersey heifers and three beef cows on the irrigated pasture last year. “We'd get into midsummer and the grass would turn brown and go dormant. Then we'd have to start feeding grain until the pasture perked back up again.”
Guell considered using a center-pivot irrigation system, but cost proved prohibitive.
“At that time, we figured it would have cost us $80,000 up front to put a center pivot on 40 acres,” he says. “Also, center pivots don't necessarily work well in a grazing setup where you have interior fences dividing a pasture into several smaller paddocks.”
The K-Line system relies on a line of polyethylene tubing to carry water from a supply source to individual, bowl-shaped, hard-plastic pods housing sprinkler heads. Individual pod numbers and the length of water line vary by operation. According to K-Line, most setups use eight to 10 pods spaced 40-50' apart, resulting in a line length of 350-500'.
Guell uses 12 pods, spaced 50' apart on a 600'-long section of tubing. The water source is a 275'-deep well with a 7.5-hp pump.
Once he starts irrigating, his goal is to apply 1-1.5" of water to about 25' of grass on either side of the tubing within 10 hours. When that goal is met, he uses an ATV to move the K-Line over to the next strip to be watered. The move takes about 10 minutes.
“There's an art to it,” says Guell. “If you drag the line in too wide of an arc, the pods can tip on you.”
He does most of his irrigating at night to take advantage of off-peak electricity rates.
Last year, he began irrigating the bluegrass, white clover and orchardgrass pasture on June 26 and continued until Aug. 20. His grazing season ended Dec. 1. While he can't say for sure how much additional pasture resulted from irrigation, he's confident that extending the grazing season to seven months helped him cut daily grain feeding costs in half.
A $2,900 grant from his electric utility helped Guell keep the cost for installing the system to just over $13,000. Major expense items included $4,700 for drilling the well and $4,200 for the pump.
Like Guell, New Holstein, WI, dairy producers Wayne and Kay Craig considered installing center-pivot irrigation on a 42-acre pasture divided into four paddocks. Instead, they opted to invest $28,000 in a K-Line system last year.
“We have some rolling terrain and thought we might have trenching problems going uphill with a center pivot,” says Wayne Craig. “The K-Line system gave us some flexibility in setting up in our different-size paddocks.”
Dry summers in 2005 and 2006 played a big part in the Craigs' decision. They milk 100 cows at their Grassway Dairy.
“We became a certified organic dairy in 2004,” Craig explains. “With the dry weather the next two years, we were short forage and had to truck in a lot of expensive hay and small grains.”
With less-than-average spring rains following very little snowmelt last year, the Craigs started irrigating July 15 when the grass began to go dormant. They stopped irrigating after rains on July 25-26, then turned on the water again for a month starting in mid-August.
“Compared to our other pastures, the grass in the irrigated pasture greened right up,” Craig says. “When the rains did hit, the grass in that pasture just exploded. It was amazing how much grass we had.”
The couple uses two water lines with 13 pods on each line, aiming to get 1” of water on the entire pasture over an eight-day period. That requires moving the line with an ATV every eight hours.
“There is a learning curve,” says Craig. For example, the manufacturer recommends moving the system while it's running to reduce stress on the water lines.
“That's not too bad in the middle of summer,” he says. “But it can be a wet and cold job once the days start shortening up and you're doing more of the work in the dark.”
Bottom line: The Craigs estimate a three- to five-year payback period for the system.
“Our goal is to make sure that we maintain nutrient density and keep the cows grazing on quality material all the time,” he says. “We think this system will play a part in helping us meet that goal.”