In collaboration with the University of Saskatchewan and the Peace Region Living Labs Project
Funded by the Beef Cattle Research Council
Objective
Current trends in pasture production are placing increased emphasis on sustainable resource management. Most pastures are commonly established as a mixture of smooth bromegrass and alfalfa as the primary species. Over time, the productivity and carrying capacity of these pastures decline because of invasion of unpalatable and less productive species, due to overgrazing and poor soil fertility.
Thus, a strategy is needed to rejuvenate these stands with persistent legumes, to supply adequate biomass of suitable nutritive value for grazing cattle. Variable results have been obtained from sod seeding legumes into depleted forage stands with factors such as species choice or pre-existing pasture species influencing results obtained over time. This suggests inclusion of binary legume mixtures in a sod-seed program may aid in improved performance and persistence of the rejuvenation technique.
Specific objectives of this project include:
1) Determine the establishment of 3 sod-seed treatments on a predominantly grass forage stand.
2) Determine yield and quality of treatments over multi-years
3) Assess treatment effects on soil C and N storage and cycling
4) Evaluate grazing animal performance
5) Economically evaluate pasture rejuvenation
6) Use these novel findings in enhanced outreach activities and increase awareness of alternative sod-seed techniques in grazing pasture systems in sustainable beef production.
Methods
The trial site is at Paul Kinnee’s pasture land located at Brownvale, AB (Legal Land Description: SE 32 83 1W6). The site has been a dense, predominantly grass-dominated pasture with a sod layer approximately 1 inch thick for the past 10 or more years, with hay occasionally harvested.
Figure 1 shows the weather (including precipitation and minimum and maximum air temperatures) from seeding until early winter recorded at the nearest AGCM Weather Station in Brownvale, AB. Overall, 2023 was characterized by low spring moisture conditions with only about 9.5" of rain obtained for the whole of the growing season.

The following 4 treatments were set out each on approximately 2-acre strips replicated twice (see Figure 2):
1. Yellowhead flower alfalfa – T1
2. Spredor alfalfa + Glenview sainfoin – T2
3. Spredor alfalfa + Cicer milkvetch – T3
4. Control (replicated thrice)

Baseline data was collected from 2-3 georeferenced points per strip.
Botanical composition was determined from clipped fresh forage material which was separated into different functional groups (grasses, legumes, forbs, weeds), weighed (and recorded), dried and reweighed for determination of % different functional groups.
Baseline forage yield (lbs/ac) and feed quality in a commercial laboratory were also determined. Surface soil water infiltration was measured using both single ring and the mini disc infiltration methods.
Surface soil temperature and moisture (volumetric moisture content, %) were determined using the FieldScout TDRⓇ 350 probe at 0-6". Soil compaction was measured using the SpotOnⓇ Digital Compaction Meter (penetrometer) at 4, 8 and 12". Soil samples were taken for bulk density determination at 0 – 6" and at 6 – 12". Also, different soil samples were taken at 0 – 6" and at 6 – 12", dried under forced air and sent to the lab for soil organic carbon, soil organic nitrogen, nitrogen, phosphorus, active cycling C & N, microbial biomass and soluble organic C & N analyses.
Sod suppression was done with glyphosate on July 4 2023 with 540 g a.i. at 1.0 L/ac before seeding. Seeding was done on July 11 with an Agrowplow DF 1000® Series No-Till Drill having 16 rows and row spacing of 6". The following seeding rates were applied:
- 10 lbs/ac for Yellow Head Alfalfa
- 27.5 lbs/ac for binary mixture of Spredor Alfalfa and Sainfoin
- 13 lbs/ac for binary mixture of Spredor Alfalfa and Cicer Milkvetch Baseline Results
Botanical Composition
The botanical composition and forage yield of the strips taken at the beginning of the trial are given in Table 1. The pasture land is predominantly grass (88%) with virtually no legumes and just over 10% weed. Timothy and brome grass were the dominant grass species while dandelion and yarrow were the dominant weeds.
Forage Yield and Quality
Forage yield averaged just about 630 lbs/ac and ranged between 320 – 1240 lbs/ac from the strips (Table 1). Ranges of 7.0% – 12.0% and 57% – 62% were reported for crude protein and TDN respectively.
Soil Properties
Results for soil compaction and water infiltration for treatment strips are given in Table 2. Penetrometer readings at all three depths exceeded 300 psi, suggesting that the pastureland may be experiencing soil compaction. Water infiltration ranged from 0.5 – 6.6 inc/hr. Bulk density was generally lower than 1.5 g/cm3 and tended to increase with depth. The bulk density ranged from 1.1 – 1.3 g/cm3 for the 0 - 6" depth and between 1.3 – 1.4 g/cm3 for the 6 – 12" depth. Soil temperature and moisture (full data not provided) taken two weeks before seeding at 4" and 8" averaged 31.7°C/5.6 % and 31.6°C/8.6% respectively. Conclusion
The baseline data prior to treatment highlighted significant issues in the pasture land, including nearly complete absence of legumes, low dry matter forage yield and poor forage quality regarding crude protein and energy, emphasizing the necessity for rejuvenation. Compaction was evident as penetrometer readings nearly doubling the 300 psi threshold were recorded, alongside low water infiltration rates. However, bulk density readings below 1.5 suggest that, despite the compaction, there may still be some movement of air and water through the soil.
The absence of moisture conditions after seeding may have accounted for the poor emergence recorded for the perennial legumes. We plan to monitor the emergence of seedlings early next spring. The second year is the planned grazing year of the project and so cattle will be introduced into the strips later in the season after assuring the emergence of seedlings. All parameters mentioned above for the baseline data will be collected again in 2024 from the georeferenced points.


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