HISTORY OF GRAZING RESEARCH IN THE ASPEN PARKLAND

The Aspen Parkland of western Canada constitutes a major portion of th e agricultural areas of Manitoba, Saskatchewan and Alberta, with 86 % of the forage production and 66% of the beef cattle herd. Although som e areas still exist in the natural state, most of the Parkland has bee n cleared of aspen (Populus tremuloides Michx.) for farming. Introduce d 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 reduct ion of the proportion of alfalfa in a mixed sward. The severity and ti me of grazing have a marked effect on pasture productivity. Bush pastu res can be renovated by using selective herbicides, fire and controlle d grazing to manage woody brush regrowth or by sod seeding of alfalfa in the depleted stands. Spring-seeded winter cereals can be grazed thr oughout the growing season or as part of a grazing rotation with peren nial forages by extending the grazing season in the fall.