Wes Woolman of Boise City, OK, counts his irrigated pasture as a competitive advantage.

He and his brother-in-law once rented more than 3,400 acres of native grass along the Oklahoma-New Mexico line. His half of their cows was about the same number as he runs now on 60 acres of irrigated cool-season grasses.

Furthermore, he pays about $75/acre for his irrigated pasture compared with about $5.50/acre for the rangeland. That's about $4,500 today vs. $9,350 for his half of the native range.

Although irrigation costs add significantly to his operating costs, they're offset by the expenses of hired part-time cowboys, gasoline and vehicular wear and tear that he once paid to operate the rangeland. Time savings and gentler cattle are other, more intangible, savings that Woolman adds to his irrigated-grass tally sheet.

He lives in a place where the rain falls rarely and the grass grows short. He also lives atop the Ogallala Aquifer, that great underground lake that made the southern half of the Great Plains into a garden spot, and is now going dry in many areas.

Because of declining water levels in the Ogallala, and because of high energy prices, interest is growing in irrigated perennial forages to replace annual crops.

Woolman uses a mixture of cool-season grasses marketed by Sharp Brothers Seed Co. Called PM6, the mix contains orchardgrass, intermediate wheatgrass, meadow brome, smooth brome and creeping foxtail.

It's a bit difficult for Woolman to put exact figures on his grazing operation because it's mated to part of his haying and cropping operation. His pivot of cool-season forage sits next to and slightly overlaps another pivot that waters half alfalfa and half other crops. Further, the two pivots share a single well.

In addition, Woolman lets the 55-60 cows graze the dormant alfalfa in winter, and also uses crop stubble or has winter/spring grazing such as oats on the cropland.

Nonetheless, Woolman's production records show that he irrigated the grass with 6-15" of water in each of the past three years — all of which were below-normal in rainfall. At an average rate of 3.25 gallons of diesel per hour to irrigate through his pivots, applying 500 gpm, Woolman uses between 2,120 and 3,027 gallons of diesel each season. At the $1.35/gallon price he paid in 2005, that adds $2,904 to $4,086 to his annual costs.

He says the 20 lbs/acre of seed cost about $46/acre, and he paid $10.50/acre to have it drilled in two directions. He also applied $50/acre worth of feedlot manure the first year. That puts his out-of-pocket establishment cost at about $106/acre. Corn seed these days costs nearly that much, and as Woolman says, “I don't have to plow anymore.”

Troy Dumler, Kansas State area economist at Garden City, says the basic budgets he ran on irrigated forages show returns similar to row cropping. However, he notes that the highest returns required high stocking rates and good animal performance.

Although Sharp Brothers Seed recommends rotational grazing for PM6, Woolman has done so only minimally. He began with the pasture divided into three paddocks, but now alternates between one cross-fence and none. The long-shooted bromegrasses in the mix need rest to thrive, but Woolman's pasture seems to be productive, anyway.

“I treat it like a supplemental crop,” says Woolman. “I water it when I have time, and when I don't need the water for the other pivot.

“I believe the grass will produce in proportion to what you put into it,” he adds. “But it really responds to moisture. It can be as brown as this road and catch a 3/10" rain and green up and leap forward.”

The spring-fall growth pattern of the cool-season forage leaves a void in his summer grazing, but he makes it up with other rented pasture or with hay.

One benefit to the summer slump is it lets the cows catch up with rapid spring growth, Woolman adds. If the grass gets too far ahead of the cows, he simply hays part of the forage and hauls it back to the cattle later.

Still, the summer slump leads Woolman to suggest that a partial circle of irrigated warm-season forage might be just the ticket to fill that gap.

“The higher fuel and fertilizer prices we're paying today will limit production, though,” Woolman says. “I'm not sure what will work in the future.”

Cool-Season Mix Gives Above-Average Production

PM6 performed well in Kansas State University tests the past three years, says Ron Hale, livestock specialist at Garden City.

The plots, at two locations in southwestern Kansas, were seeded to a number of warm- and cool-season forages. They were irrigated to provide a minimum of 22” of water annually, which is more water than some producers actually apply.

The mixture, plus several individual species, came in at or above the two-year cool-season production average of about 11,000 lbs/acre. The individual grasses included intermediate wheatgrass, Lakota matua, MaxQ tall fescue and smooth bromegrass.

All the cool-season forages were harvested once at late boot to early head stage in early summer, then again in fall.

The warm-season grasses were harvested up to three times a year, depending on conditions and variety. In the first year of testing, yields ranged from 1,654 lbs/acre for common crabgrass to about 12,200 lbs/acre for switchgrass and eastern gamagrass. Three varieties of bermudagrass averaged 10,300-11,800 lbs/acre.