Climate change and winter survival of perennial forage crops in eastern Canada

Severe winter climatic conditions cause recurrent damage to perennial forage crops in eastern Canada. Predicted increases of 2 to 6 C in minimum temperature during winter months due to global warming will likely affect survival of forage crops. Potential impacts of climate change on overwintering of perennial forage crops in eastern Canada were assessed using climatic indices reflecting risks of winter injuries related to cold intensity and duration, lack of snow cover, inadequate cold hardiness, soil heaving, and ice encasement. Climatic indices were calculated for 22 agricultural regions in eastern Canada for the current climate (1961-1990) and future climate scenarios (2010-2039 and 2040-2069). Climate scenario data were extracted from the first-generation Canadian Global Coupled General Circulation Model. Compared with current conditions, the hardening period in 2040 to 2069 would be shorter by 4.0 d, with a lower accumulation of hardiness-inducing cool temperatures. The period during which a temperature less than or equal to-15degreesC can occur (cold period) would be reduced by 23.8 d, and the number of days with snow cover of at least 0.1 m would be reduced by 39.4 d. Consequently, the number of days with a protective snow cover during the cold period would be reduced by 15.6 d. Under predicted future climate, risks of winter injury to perennial forage crops in eastern Canada will likely increase because of less cold hardening during fall and reduced protective snow cover during the cold period, which will increase exposure of plants to killing frosts, soil heaving, and ice encasement.