Benefits include a boost in production, improved palatability, nitrogen enhancement and increased carbon storage
Incorporating legumes into grass pastures boosts the pasture and also provides good feed for the late-summer slump in plant production, said Dr. Bart Lardner from the University of Saskatchewan.
He told the Saskatchewan Beef Industry Conference that grazing during August and September, when plants get dry and mature, can be a concern.
Including a legume improves palatability while adding nitrogen to the soil to help enhance the pasture.
Lardner said an added benefit is that the more deep-rooting plants farmers can include in mixtures, the more carbon they can store.
Alfalfa is the “queen of the forages,” he said, but producers obviously worry about bloat. Mixing alfalfa into a grass stand can reduce that concern, and newer varieties may help. There are also newer varieties of sainfoin; older varieties were known for low persistence.
A three-year study in Saskatchewan, at Swift Current and Lanigan, examined four mixtures of legumes and grasses to graze steers.
The mixes included Yellowhead alfalfa with Success hybrid brome, Yellowhead alfalfa with Tom Russian wild rye, Mountainview sainfoin with Success hybrid brome, and Mountainview sainfoin with Tom Russian wild rye.
Lardner said Yellowhead is a Siberian type of alfalfa that in previous work showed a 90-percent survival rate in grass mixtures under heavy grazing.
Mountainview sainfoin produces 42 percent greater biomass and 13 percent lower fibre content compared to older varieties, he said.
“Russian wild rye is a long-lived, deep-rooted drought- and saline-tolerant species,” Lardner said. “The recommendation is to best use it as a late-season pasture species.”
Newer varieties like Tom yield 19 to 22 percent better than earlier types.
Finally, hybrid brome is a cross between smooth and meadow brome. Smooth brome is typically used for haying while meadow brome is grazed. Hybrid is a dual-purpose forage that can be used either way.
Lardner said the Success variety yields 103 percent of Fleet meadow brome but only 96 percent of Carlton smooth brome.
The study included 16 two-acre replicate paddocks at both sites, separated by portable electric fence. Steers entered the study at 750 pounds and were randomly allocated to a treatment.
At Lanigan, 64 Angus steers grazed for 30 to 40 days in August-September, while at Swift Current 48 yearling steers grazed for between 34 and 47 days.
The forage yield at Swift Current in the four treatments ranged from 3,500 to 3,900 pounds per acre over the three years, Lardner said. The ratio of legume-to-grass content was about 34:66.
At Lanigan, the yield ranged from 2,900 to 5,000 lb. per acre and the legume-to-grass ratio was 15:85.
Lardner said a 750-lb. steer needs about 60 percent energy and 8.5 percent crude protein to gain 1.5 lb. per day.
The analysis showed these binary mixtures were able to meet those requirements.
At Swift Current, the steers gained between 45 and 62 lb. for an average daily gain of between 1.6 and 1.9 lb. They gained this on the alfalfa-hybrid brome mix in the brown soil zone. The best forage yield was on a legume with Russian wild rye.
The Lanigan steers showed an average daily gain of between 1.3 and 2 lb. per day, with total gains of 33 to 48 lb. The best gains were on sainfoin-Russian wild rye.
However, in the dark brown, thin black soil zone at Lanigan, the greatest yield was on a legume plus hybrid brome grass.
Lardner said the soil zone and species adaptation influence yield and biomass growth, the germination and establishment of both and the quality, protein, and energy content.
“Binary mixtures such as these different grass and legume species in combination and in different ratios did show promise for late-summer or fall grazing in either south or central Saskatchewan,” he said.
More research is needed in the aspen parkland area of the province where much of the cattle population is located.
Lardner added cicer milk vetch is making a comeback, as producers look at the benefits of forage-based systems in rotation or long-term in carbon sequestration.
“This carbon tax is weighing heavy on us all and we need to do things and get the information out there to help producers combat those misinformations that are out there,” he said.