Plant community composition in pastures seeded with native plant species in southwest Saskatchewan

Pastures made of native species offer good quality forage for grazing in the warm and dry months of July and August in southwestern Saskatchewan, when cool season species loose feeding quality. Long-term research plots were seeded with seven native grass species, with or without either purple prairie clover or alfalfa to further increase forage quality and sustain high productivity. These stands were compared to meadow brome – alfalfa stands. Triple superphosphate was applied at a rate of 0, 50 or 200 kg P2O5 ha-1 in an attempt to enhance root growth and facilitate establishment. Phosphorus fertilization had no effect on root length density, plant biomass, or plant proportions. Very little growth was produced in 2006, the year of seeding. But stands grew rapidly in 2007 and in the first week of July, pastures with native grasses produced 1.5 t ha-1, i.e. approximately half the biomass of meadow brome – alfalfa stands. The late season species, blue grama, little bluestem and purple prairie clover, were just starting their growth cycle in 2007 at that time and larger herbage yield in native stands is expected in 2008. Purple prairie clover made up less than 1% of the biomass of stands where it was seeded and alfalfa, about 14%. Weeds, which were abundant in 2006, were effectively suppressed by the forage plants in 2007, particularly in meadow brome – alfalfa stands. We conclude that stands seeded with native species require a longer period of establishment than meadow brome stands. This establishment period could not be enhanced by P fertilization.