Pivots Out, Line-Pod Irrigation In for Pasture
by Allan Nation, (Reprinted from the August 06 Volume of “The Stockman Grass Farmer” magazine.)
Ignacio, Colorado: Colorado sheep rancher, Richard Parry, told attendees of The Stockman Grass Farmer's Sheep Production School that he planned to replace his center pivot irrigation with line-pod irrigation.
He explained this decision with a succinct, "No moving parts."
#1 Rule In Pasture Irrigation
"Rule one in irrigation is "The more moving parts the more maintenance and frustration."
With line-pod irrigation, an ATV is used to move irrigation pods that are permanently connected to a flexible water delivery hose.
Parry said he has learned that in irrigation "simplicity is everything."
He has used flood, side-roll, gated pipe, fixed risers, center-pivots and line-pod on his thousand-acre, high altitude Rocky Mountain ranch.
After two years of trial, he said he now plans to convert his whole ranch to linepod irrigation.
Parry said he felt flood irrigation had no place in a grazing operation because it was water wasteful and led to pugging, parasitism, and a host of other problems.
"You need to use spray irrigation with animals."
He said flood irrigation and gated pipe were the first form of irrigation to go on his ranch.
Side-rolls are very labor-intensive and are subject to wind damage.
Fixed risers cannot be used with cattle but do well with sheep.
Unfortunately, fixed risers prevent the planting of winter annuals and Parry uses cold-tolerant annuals to grass-finish lambs during the winter months.
Parry said that these winter annuals (cereal rye and annual ryegrass in separate paddocks) allow him to sell fresh lamb to area restaurants seven months of the year from one May lambing.
While primarily a sheep ranch, Parry custom grazes beef cattle to control spring pasture growth and reduce parasitism in the sheep.
The ranch is Certified Organic.
CENTER PIVOTS CREATE PROBLEMS
He said center-pivots are considered low-labor and initially they are.
But as they age they become a maintenance headache with their many motors.
"There is no more helpless feeling than watching your pastures shrivel up while you wait for a technician to come and repair your center- pivot."
"They also cut deep ruts into permanent pasture, particularly if they have to climb a hill."
He said he spent $7500 to fill the ruts on just one center-pivot circle.
He prefers the K-line brand of line-pod because their pods stay upright better when being moved.
He said he moves his line-pods every 24 hours.
"A 24 hour shift was a wonderful change. We used to call the side-rolls our dairy cows because they demanded attention every 12 hours."
He said the sheep are normally grazed two days ahead of the irrigation. In other words, the irrigation is following the sheep through their rotation.
"You don't want to irrigate in front of, or over, animals to protect your pastures from pugging."
He said maintaining a stand of perennial ryegrass and white clover in semi-arid Western conditions requires the application of three inches of water every 24 hours.
"You need to build your irrigation system for the hottest, driest day of the year."
He said that white clover requires more water than alfalfa but does not lignify in hot weather as alfalfa does.
"We use white clover in the same way some graziers use summer annuals to keep their hot weather gains up."
"To pasture finish lambs we want them to gain a minimum of 10 pounds a month every month."
GRAVITY FLOW PRESSURE
Because the line-pods only require 30 to 50 pounds of pressure to operate, Parry's line pods run completely on gravity-created pressure.
"You only need a drop of 100 feet to run them on gravity flow pressure," he said.
He said line-pod irrigation works well with connected surface water catchments that allow for a technique called "rain-harvesting."
"You need to develop a renewable source of irrigation water."
"Build these catchments higher than your primary pasture so you can run your irrigation on gravity pressure and avoid pumping energy expenses."
He said a line-pod development including main and spur waterline development and fixed risers cost around $350 an acre.
For direct marketers such as himself, he said that is roughly the cost of one lamb.
Parry said the higher the soil organic matter is the more effective your irrigation will be.
"Grazing at high stock densities with frequent moves will quickly build soil organic matter."
He said fertilizing with gypsum also helps make irrigation more effective by preventing soil capping.
Parry doesn't believe irrigation should be used as a primary means to increase per acre production.
"Irrigation is most cost-effective when it is used to fill the low spots in your natural forage flow and to keep slaughter animal gains high.”