Longevity and Ecosystem Services of Perennial Forage Mixtures
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Funded by Results Driven Agriculture Research (RDAR)
Perennial forage is key to beef cattle production systems. This project evaluates the long-term performance of already established perennial forage stands, both as mixtures and monocultures (pure grasses and pure legumes), across two locations in the Peace Region: Fairview and DeBolt. Research on the longevity of perennial forages is vital for developing resilient, cost-effective forage systems amid climate change and price volatility in forage seed and beef cattle markets.
Objectives
Determine the Dry Matter (DM) Yield and nutritional value of perennial forage mixtures, monoculture grasses, and legumes.
Evaluate the effects of legumes (in both pure stands and mixtures) on water-use efficiency.
Assess weed suppression, longevity, and the decline of forage stand over time.
Methods
The project was implemented at the Fairview Research Farm (FRF) (Range Rd. 35) and DeBolt (Township Rd. 740). The stands in Fairview were established in June 2020, whereas those at the DeBolt site were seeded in May 2021.
Grass species/varieties, legume species/varieties, and grass-legume mixtures were established in separate blocks, each replicated four times, using small plots measuring 8 m × 1.14 m. Seeding was conducted with a 6-row Fabro Small Plot Drill, featuring disc-type openers spaced 23 cm apart and equipped for side banding.
The forage nutritive value indicators presented here are on a dry matter basis.
In Field Observations
Fairview Research Farm site: Forage stands received sporadic precipitation from mid-May until mid-June. After this, the site was hit with a temporary dry spell until forage harvest. A closer look at the individual species within mixtures showed that the proportions of sainfoin species had declined similarly to monoculture sainfoin stands.
DeBolt site: Received precipitation was fairly well distributed during the growing season. The sainfoin had declined within stands, but AC cicer milkvetch and birdsfoot trefoil had increased significantly in proportions.
Figure 1. Legume variety plots at the DeBolt site
Results
Forage Dry Matter (DM) Yield
Fairview Site
Legume Varieties (27 Tested Varieties):
We observed significant differences in DM yield among the legume species and varieties.
The top five highest-yielding legume varieties varied from 5,489 to 5,779 lbs/ac for Rugged alfalfa, Spredor 4 alfalfa, Boost HG alfalfa, Anik alfalfa, and AC Grazeland alfalfa (Table 2).
Lowest yielding legumes:
AC Mountainview sainfoin (2,697 lbs/ac)
AC Veldt cicer milkvetch (2,481 lbs/ac)
Bull birdsfoot trefoil (2,093 lbs/ac)(Table 2)
Monoculture Grasses:
Forage DM yield also varied widely among grasses.
Top five highest yields (Table 2):
AC Saltlander wheatgrass: 3,528 lbs/acto Palatin reed canarygrass: 2,172 lbs/ac
Lowest yields:
Fojtan festulolium: 590 lbs/ac to AC Success hybrid bromegrass: 699 lbs/ac(Table 2)
Forage Mixtures:
Forage mixtures also differed widely in DM yield.
Top five highest-yielding mixtures, out of 24 mixtures (Table 2):
Meadow bromegrass + Greenleaf pubescent wheatgrass + AC Yellowhead alfalfa (M11): 5,176 lbs/ac
AC Success hybrid bromegrass + AC Yellowhead alfalfa (M3): 4,730 lbs/ac
Lowest-yielding mixtures:
M0: 1,773 lbs/ac
M13: 1,973 lbs/ac(Table 2)
Overall, the DM yield of forage harvested from the Fairview site followed the order legumes > mixtures > grasses.
DeBolt Site
Legumes (20 Tested Varieties):
Also widely varied in DM yield.
Top five highest-yielding alfalfa varieties:
Rugged alfalfa: 8,045 lbs/ac to AC Yellowhead alfalfa: 7,374 lbs/ac (Table 3)
Lowest-yielding legumes (Table 3):
Bull birdsfoot trefoil: 5,080 lbs/ac
AC Veldt cicer milkvetch: 3,133 lbs/ac
AC Mountainview sainfoin: 2,338 lbs/ac
Monoculture Grasses:
Significant differences in DM yield existed.
Highest yielding monoculture grass:
Greenleaf pubescent wheatgrass: 4,393 lbs/ac
Lowest yielding monoculture grass:
Savoury tall fescue: 1,812 lbs/ac(Table 3)
Forage Mixtures (15 mixtures):
Significant variations in DM yield (P<0.05).
Top five yielding mixtures:
Haymix: 9,937 lbs/ac to Cattlemans forage mix: 7,703 lbs/ac
Lowest three yielding mixtures:
All Grass Pasture mix “0” from Golden Acres: 4,574 lbs/ac
Bloat-free legume mix (33% AC Mountainview sainfoin + 33% AC Veldt cicer milkvetch + 33% birdsfoot trefoil): 4,138 lbs/ac
Horsemans Forage mixture: 3,892 lbs/ac
Overall, the forage mixtures yielded higher than both monoculture legumes and grasses. The trend of DM yield was forage mixtures>legumes>grasses.
Forage Nutritive Value
Many forage nutritive value measurements were evaluated, however, a selected few have been reported here. This includes Crude Protein (CP), Total Digestible Nutrients (TDN), and Relative Feed Value (RFV).
Fairview Site
Crude Protein (CP)
Significant differences were observed in monoculture grasses and mixtures, but no differences in monoculture legumes were seen.
Legumes:
Top five legumes (highest CP):
Spredor 5 alfalfa: 16.3% to Dalton alfalfa: 16.8%
Lowest CP legumes:
AC Veldt cicer milkvetch: 14.8%
Bull birdsfoot trefoil: 13.5%
AC Mountainview sainfoin: 13.5%
Monoculture grasses:
Top five grasses (highest CP)
Killarney orchard grass: 12.9% to Cowgirl tall fescue: 11.9%
Lowest CP legumes:
Rocky Mountain fescue: 8.2%
Forage Mixtures:
Highest in legume-dominated mixtures, e.g., AC Yellowhead alfalfa + Rugged alfalfa + AC Veldt cicer milkvetch + AC Mountainview sainfoin + birdsfoot trefoil (M16): 17.3%
Lowest in grass-only mixtures, e.g., AC Success hybrid bromegrass + Greenleaf pubescent wheatgrass + Kirk crested wheatgrass + Italian ryegrass + smooth meadow bromegrass (M13): 9.5%
Overall CP Trend: Legumes > Grass-legume mixtures > Grass-only mixtures.
Total Digestible Nutrients (TDN):
Significant differences across legumes, grasses, and mixtures were observed.
Legumes:
Top five legumes (highest TDN):
AC Mountainview sainfoin and AC Veldt cicer milkvetch: 61.4%
Lowest TDN legumes:
HPS premium coated alfalfa: 55.9%
Monoculture Grasses:
AC Saltlander wheatgrass: 60.4%
Killarney orchard grass (highest TDN): 64.3%
Forage Mixtures:
Highest in grass-only mixtures, e.g., AC Success hybrid bromegrass + Greenleaf pubescent wheatgrass + Kirk crested wheatgrass + Italian ryegrass + smooth meadow bromegrass (M13): 61.2%
Lowest in legume-dominated mixtures, e.g., AC Mountainview sainfoin + Spredor 5 alfalfa + AC Veldt cicer milkvetch (M14): 55%
Overall TDN Trend: Monoculture grasses > All-grass mixtures > Legumes.
Relative Forage Value (RFV):
Legumes:
Top five legumes (highest RFV):
Boost HG alfalfa: 119.3 to Peace alfalfa: 112.8
Lowest RFV legumes:
Algonquin alfalfa: 102.3
AC Yellowhead alfalfa: 103.7
Halo alfalfa: 100.8
Monoculture Grasses:
Highest RFV grass forage:
HTK or festulolium: 112.9
Lowest grass forage:
Rocky Mountain fescue: 82.0
Forage Mixtures:
Highest in legume and grass-legume mixtures, e.g., AC Success hybrid bromegrass + Greenleaf pubescent wheatgrass + AC Yellowhead alfalfa: 108.3
Lowest in all-grass mixtures, e.g., Fleet meadow bromegrass + AC Yellowhead alfalfa + AC Mountainview sainfoin (M0): 91.5
Overall RFV Trend: Legumes > Grass-legume mixtures > Monoculture grasses.
A higher RFV means better forage quality — more digestible and more intake, which typically supports better beef cattle performance.
DeBolt Site
Crude Protein (CP)
Significant differences in CP for monoculture grasses, legumes, and mixtures (P<0.05).
Legumes:
Top five legumes (highest CP):
AC Veldt cicer milkvetch: 18.8%
Lowest CP legumes:
AC Mountainview sainfoin: 15.8%
Algonquin alfalfa: 15.7%
Anik alfalfa: 13.6%
Monoculture Grasses:
Cowgirl tall fescue (highest): 11.2%
Kirk crested wheatgrass (lowest): 6.6%
Forage Mixtures:
Highest in all-legume mixtures, e.g., AC Yellowhead alfalfa + Rugged alfalfa + AC Veldt cicer milkvetch + AC Mountainview sainfoin + birdsfoot trefoil: 17.5%
Lowest in grass mixtures, e.g., All Grass Pasture Mix “0” from Golden Acres: 6.9%
Overall CP Trend: Legumes > Grass-legume mixtures > Monoculture grasses.
Total Digestible Nutrients (TDN)
Significant differences in TDN for grasses, legumes, and mixtures (P<0.05).
Legumes:
Top five legumes (highest TDN):
AC Veldt cicer milkvetch: 62.2%
Lowest TDN legumes:
Halo alfalfa: 52.1%
Rugged alfalfa: 51.7%
Beaver alfalfa: 50.5%
Monoculture Grasses:
Highest TDN:
Fojtan festulolium: 61.4%
Milkway tall fescue: 59.9%
Forage Mixtures:
Highest in all-grass mixtures, e.g., All-grass mix: 59.3%
Lowest in legume-dominated mixtures, e.g., All-legume mix: 48.7%
Overall TDN Trend: Grass forages > Grass-only mixtures > Legume mixtures.
Relative Forage Value (RFV)
Legumes:
Top five legumes (highest RFV):
AC Veldt Cicer Milkvetch: 112.4
AC Mountainview Sainfoin: 105.3
Bull Birdsfoot Trefoil: 103.3
Lowest RFV legumes:
Beaver Alfalfa: 86.4
Grass Monocultures:
Highest RFV grasses:
Fojtan festulolium: 91.2
Comtail timothy: 88.9
Richmond timothy: 85.7
Lowest RFV grasses:
AC Success hybrid bromegrass: 70.8
Forage Mixtures:
Highest in legume-dominated mixtures, e.g., Bloat-free legume mix: 97.4
Lowest in all-grass mixtures, e.g., All Grass Pasture Mix “0” from Golden Acres: 70.7
Overall RFV Trend: Legumes > Grass-legume mixtures > Monoculture grasses.
Conclusion
Forage Dry Matter (DM) Yield
The DM yield results from both sites demonstrated that alfalfa varieties outperformed other legume species, such as sainfoin, cicer milkvetch, and birdsfoot trefoil. Among the top-performing varieties, Rugged alfalfa yielded the highest DM at both the Fairview (5,779 lbs/ac) and DeBolt (8,045 lbs/ac) sites. Similarly, the Legumaster mixture (55% sainfoin, 25% cicer milkvetch, 20% Spredor 5 alfalfa) also showed high DM yield, suggesting these varieties are adaptable to various agro-ecological zones.
At the Fairview site, legumes generally had higher DM yields than monoculture grasses and grass-legume mixtures. At DeBolt, grass-legume mixtures outperformed monoculture grasses and monoculture legumes. Overall, monoculture grasses and all-grass mixtures exhibited the lowest DM yields across both sites. However, grasses such as reed canary grass, meadow brome, and wheat grasses demonstrated the potential for high forage productivity.
Crude Protein (CP)
The CP content varied significantly across forage types. The highest CP values were found in AC Veldt cicer milkvetch (18.8%) and all-legume mixtures (17.3%). Grasses, on the other hand, generally had lower CP values. Most of the forages met the CP requirements for beef cattle across different categories (7-9-11%). However, grasses like Peak brome, Kirk crested wheatgrass, and all grass Pasture mix “0” fell short of the 7% CP threshold.
Total Digestible Nutrients (TDN)
TDN values ranged from 48.7% to 64.3% across all treatments. Monoculture grasses and all-grass mixtures showed the highest TDN, with orchard grass exceeding 64%. Legumes and legume-dominated mixtures generally had lower TDN values. Many legume-dominated mixtures did not meet the TDN requirements for beef cattle during mid-gestation (55%), late-gestation (60%), and post-calving (65%). In contrast, monoculture grasses and all-grass mixtures met the required TDN levels. Since TDN is essential for maintaining body temperature during extreme weather (such as winter), producers feeding low TDN diets will need to supplement, which can increase production costs.
Relative Forage Value (RFV)
RFV, an indicator of forage intake and digestibility, was higher in legumes and legume mixtures compared to monoculture grasses and grass mixtures. All alfalfa varieties, sainfoin, birdsfoot trefoil, and cicer milkvetch had higher RFV, meaning these legumes offer better intake and digestibility. In comparison, grasses showed lower RFV values.
Note: The first five are the varieties with superior nutritive value, whereas the last three are those with low nutritive value.
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