Grazier-friendly irrigation debuts in U.S.
But smaller, grazier-friendly irrigation systems are starting to make their way to the U.S. This year Graze visited two grass farms in very different climatic situations that have started using one of them, the "K-Line Irrigation" system from New Zealand. Both were at least moderately happy with their early results.
In eastern Kansas, Carl Nichols (see page 1) this year employed his system almost continuously for three months until the extreme Plains drought forced him to shut down in mid-August due to lack of retention pond water. Nichols estimates that the irrigation grew an extra ton of pasture per acre on 13 acres, at a cost of $100/month for pumping. With alfalfa hay prices above $100/ton in his area, Nichols says his $3,000 investment in the K-Line system should be paid back after two years of use.
While coming nowhere close to satisfying the requirements of his 200cow herd, Nichols said the irrigated pasture was "icing" that helped milk production during a tough summer. "It was better than the $100 per ton alfalfa hay," he asserted.
Meanwhile, near Waupun in eastern Wisconsin, Steve Guell had plenty of rain through much of the growing season. Guell ended up applying just two inches of irrigation water in one pass over 30 acres of white clover, bluegrass and orchard grass pasture, while half of that acreage received two passes totaling four inches.
He spent $13,200 to set up his system, which includes a 275-foot well with a six-inch casing, a 7.5-horsepower electric pump, and running a buried electric line 500 feet from the utility pole. This was a net cost that included a $2,900 grant from his electric utility.
By using the system only at night, and thus spending 4.2 cents/KwH (less than one-fourth the peak rate), Guell's electric bill for the period he irrigated (July through early September) came to $150.
Guell says he grew more pasture because of the irrigation, but isn't sure how much. What he is sure of is that irrigation allowed him to cut daily grain feeding in his Jersey herd from 12 to 8 lbs. /cow. "I think I'm getting better quality pasture, which is more important than yield," he asserts.
K-Line is a surface irrigation system based on hard plastic "pods" that protect small sprinkler heads. Multiple pods are connected with poly pipe (standard diameter about 1.6 inches), which in turn is usually connected to larger-diameter (about 2-inch) poly pipe bringing water from the supplying pump. Individual systems can differ in length and number of sprinkler pods: Guell has 12 pods on a 600-foot run, while Nichols' system has 13 pods in 650 feet.
Water application rates are also adjustable. Guell sets his well head pressure at 70 p.s.i., which delivers about 45 pounds at the end of the line. As is the case with Nichols's system, each of the sprinklers covers a 50-foot diameter. Guell's well is capable of providing 50 gallons of water per minute, and he aims to deliver about two inches of water over a period of 10 hours each night to nearly an acre of pasture.
Nichols uses a two horsepower electric pump set at 55 p.s.i., applying about 1.2 inches to half an acre over a 12-hour period.
Both graziers say that moving their systems requires no more than 15 minutes. Guell uses a tractor, while Nichols employs an ATV.
Among the weak points, according to New Zealanders who've used such systems, is that the pods are more difficult to drag through taller forage, and irrigation can become infeasible when plants become too tall. Nichols and Guell report no such problems, although Nichols says he's concerned about how he'll irrigate sorghum-sudan grass if he plants it next year. Guell notes that there's an art to moving the pods, as they can tip if the irrigation line is dragged in too wide an arc.
The ground pod system also requires that fences be placed to allow for efficient movement of the lines. (Nichols installed a guard at the front of his ATV for driving over fences.) .
Guell says he could provide at least some water to virtually his entire, 54 acre dairy grazing bloc with the addition of a 500-foot extension from the well. Or, he could apply even more water by running a second irrigation line without losing more than a couple of pounds of pressure. The system comes with a variety of sprinkler heads, including one that would apply as little as a tenth of an inch of water per hour.
In addition to allowing better forage quality, Guell says he wants to use the system to extend his grazing season, as daily feed costs on pasture average $1.10 per cow, or half his winter average.
Nichols's primary problem is a limited water supply in his high-evaporation part of the world. He ran the system for all but three or four days during a three-month period last summer, and had to shut down because his retention pond was getting too low to serve its other purpose of providing cattle water.
He figures he needs at least half an acre-foot of retention pond water for every acre irrigated. The 13 acres he tried to irrigate this year was probably about three acres too many for the single system, as a little over an inch every 10 days would probably come closer to doing a proper job, he says.
The Nichols family has constructed a new retention pond, and Carl feels that 40 acres watered by at least four K-Line systems is a good short-term goal.