HISTORY OF GRAZING RESEARCH IN THE ASPEN PARKLAND

The Aspen Parkland of western Canada constitutes a major portion of the agricultural areas of Manitoba, Saskatchewan and Alberta, with 86 % of the forage production and 66% of the beef cattle herd. Although some areas still exist in the natural state, most of the Parkland has been cleared of aspen (Populus tremuloides Michx.) for farming. Introduced pasture species have been seeded, and bromegrass (Bromus inermis L.) and alfalfa (Medicago spp.) have been found to be the most productive. The addition of nitrogen and phosphorus fertilizer has been shown to nearly triple forage production in the presence of adequate moisture and favorable temperatures. Straight nitrogen has resulted in a reduction of the proportion of alfalfa in a mixed sward. The severity and time of grazing have a marked effect on pasture productivity. Bush pastures can be renovated by using selective herbicides, fire and controlled grazing to manage woody brush regrowth or by sod seeding of alfalfa in the depleted stands. Spring-seeded winter cereals can be grazed throughout the growing season or as part of a grazing rotation with perennial forages by extending the grazing season in the fall.