Multiple global climate models suggest that the Canadian Prairies will experience temperature increases due to climate warming. This could influence pasture and grazing production. Three climate scenarios CGCM2 A21, CSIROMk2 B11 and HadCM3 A21 were used to predict daily weather data to 2099 and incorporated into the GrassGro decision support tool to project pastoral production during 30-year increments, 2010 to 2099. Simulations were compared with the World Meterological Organization baseline years, 1961-1990 at two sites (Saskatoon and Melfort) and two soil textures (loam topsoil / loam subsoil and sandy-loam / sandy-clay-loam). Two tame grasses [crested wheatgrass (CWG; <i>Agropyron cristatum</i>) and hybrid bromegrass (HBG; <i>Bromus inermis x Bromus riparius</i>) and a mixed native pasture (<i>Festuca hallii; Elymus lanceolatus; Pascopyrum smithii; Nassella viridula</i>) were studied at each location.<p> Soil moisture was greater for loam/loam than sandy-loam/sandy-clay-loam resulting in more plant available moisture in all climate scenarios at both locations. However, plant available moisture alone was unable to explain changes in pasture dry matter (DM) production. The results projected from CGCM2 A21 were more favorable to plant and livestock production than those of CSIROMk2 B11 and HadCM3 A21. CGCM2 A21 simulated increases in mean DM production of HBG at both locations during spring each 30-yr period (P<0.05) but an overall decline (P<0.05) in mean average daily gain (ADG) of steers at Melfort, whereas at Saskatoon there was an increase in ADG (P<0.05). CWG decreased in DM production at Melfort during summer and increased at Saskatoon with CGCM2 A21 but there was an overall decrease in ADG of steers during each 30-yr period relative to baseline. It was concluded that HBG was better able to stabilize production under various future climatic conditions than CWG. There was a shift in species dominance from <i>Festuca hallii</i> to <i>Elymus lanceolatus</i> in the mixed native pasture at both locations associated with the increase in summer temperatures. This suggests that various grass species may respond differently to climate change.These results indicate that climate change will cause significant changes in soil moisture, productivity and quality of tame pastures, liveweight of grazing cattle and species composition of native pasture.

Multiple global climate models suggest that the Canadian Prairies will experience temperature increases due to climate warming. This could influence pasture and grazing production. Three climate scenarios CGCM2 A21, CSIROMk2 B11 and HadCM3 A21 were used to predict daily weather data to 2099 and incorporated into the GrassGro decision support tool to project pastoral production during 30-year increments, 2010 to 2099. Simulations were compared with the World Meterological Organization baseline years, 1961-1990 at two sites (Saskatoon and Melfort) and two soil textures (loam topsoil / loam subsoil and sandy-loam / sandy-clay-loam). Two tame grasses [crested wheatgrass (CWG; <i>Agropyron cristatum</i>) and hybrid bromegrass (HBG; <i>Bromus inermis x Bromus riparius</i>) and a mixed native pasture (<i>Festuca hallii; Elymus lanceolatus; Pascopyrum smithii; Nassella viridula</i>) were studied at each location.<p> Soil moisture was greater for loam/loam than sandy-loam/sandy-clay-loam resulting in more plant available moisture in all climate scenarios at both locations. However, plant available moisture alone was unable to explain changes in pasture dry matter (DM) production. The results projected from CGCM2 A21 were more favorable to plant and livestock production than those of CSIROMk2 B11 and HadCM3 A21. CGCM2 A21 simulated increases in mean DM production of HBG at both locations during spring each 30-yr period (P<0.05) but an overall decline (P<0.05) in mean average daily gain (ADG) of steers at Melfort, whereas at Saskatoon there was an increase in ADG (P<0.05). CWG decreased in DM production at Melfort during summer and increased at Saskatoon with CGCM2 A21 but there was an overall decrease in ADG of steers during each 30-yr period relative to baseline. It was concluded that HBG was better able to stabilize production under various future climatic conditions than CWG. There was a shift in species dominance from <i>Festuca hallii</i> to <i>Elymus lanceolatus</i> in the mixed native pasture at both locations associated with the increase in summer temperatures. This suggests that various grass species may respond differently to climate change.These results indicate that climate change will cause significant changes in soil moisture, productivity and quality of tame pastures, liveweight of grazing cattle and species composition of native pasture.