Pasture Rejuvenation Using Sainfoin and Cicer Milkvetch in Western Canada

Sod-seeding of depleted pastures with non-bloating legumes can be a low-cost pasture rejuvenation strategy for ranchers in the North American prairies. A study was conducted to determine if sainfoin (Onobrychis vicifolia subsp. vicifolia) or cicer milkvetch (CMV) (Astragalus cicer L.) populations or cultivars (hereinafter populations) can be used to rejuvenate alfalfa (Medicago sativa L.) or grass pastures. The study included sainfoin populations with increased fitness to grow with alfalfa and CMV cultivars that were selected for early emergence and rapid seedling growth. These populations were seeded using three seeding methods: traditional re-seeding, drilling seed with Great Plains drill, or Pan drill, using split-plot randomization at three locations in Alberta in 2015 or 2016. Lethbridge had pre-existing alfalfa while Ponoka and Red Deer were predominantly grass pastures. The sod-seeded rejuvenation, as indicated by percentage dry matter (DM) contributed by newly planted species succeeded at Lethbridge (>= 15), failed at Ponoka (similar to 1), and partially succeeded at Red Deer (>= 9). Successful establishment of new plants did not increase the total forage mass of the rejuvenated pasture. Sainfoin populations established better and contributed greater forage mass compared to CMV cultivars when sod-seeded on alfalfa pasture, but the improvement was not consistent on grass pasture. Forage nutritive values were not different among populations within species, but pasture seeded with CMV cultivars had greater crude protein than unseeded plots. Sod-seeded grass-legume pasture had greater crude protein than unseeded plots at Red Deer. Sod-seeding alfalfa pasture with sainfoin populations can be an efficient pasture rejuvenation strategy.