| John Waddington, Duane H. McCartney, and Leonard P. Lefkovitch |
| Authors are research scientist (retired), Agriculture and Agri-Food Canada Research Centre, P.O. Box 1030, Swift Current, SK, S9H 3X2; pasture research leader, Agriculture and Agri-Food Canada Research Farm, Melfort, SK, S0E 1A0; and statistician (retired), Agriculture and Agri-Food Canada Research Branch, Headquarters, (Western Region), Ottawa, ON, K1A 0C6, Canada. At the time of the research, the senior author was a research scientist at Melfort. |
Abstract |
| The effects of grazing, fertilizing, and seeding on persistence of herbaceous species was monitored by point quadrat about every second year from 1975 to 1989 in a low-fertility pasture in the aspen parkland vegetation zone of east-central Saskatchewan, Canada. Ground cover response to continuous grazing was contrasted with that of 4- and 6-paddock rotationally-grazed areas fertilized in the fall of every other year with 90 kg N, 45 kg P2O5, 10 kg S ha-1. The original vegetation in 2 paddocks of the 6-paddock system was replaced with Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski) in 1976, and in 1 of the other 4 paddocks in turn with smooth brome (Bromus inermis Leyss.)-alfalfa (Medicago sativa L.) in 1979 and 1981, crested wheatgrass (Agropyron cristatum (L.) Gaertn.) in 1983, and a meadow brome (Bromus riparius Rehm.)-alfalfa mix in 1985. Initially, smooth brome and creeping red fescue (Festuca rubra L.) dominated the vegetation with ground cover estimates of 10–20% and 40–60%, respectively. Alfalfa ground cover was less than 1%. With the changes in management, Kentucky bluegrass (Poa pratensis L.) replaced creeping red fescue. Alfalfa increased until 1980 and then declined to its original level, apparently in response to precipitation trends. Russian wildrye almost died out and was replaced by brome and Kentucky bluegrass. Reseeding with smooth bromegrass-alfalfa did not consistently increase brome ground cover beyond that obtained by rotational grazing and fertilization, and increased alfalfa only temporarily. Cultivation during the summer before spring seeding resulted in partial recovery of the old vegetation and invasion by Kentucky bluegrass. Total ground cover varied from year to year in response to spring precipitation. Forbs usually increased after reseeding, but declined to their original levels within 5 years. |
| Key Words: Bromus inermis, Medicago sativa, Psathyrostachys juncea, Agropyron cristatum, Bromus riparius, grazing system, seeding, fertilizing |