Climate Change and Winter Survival of Perennial Forage Crops in Eastern Canada

Abstract

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 ≤−15°C 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.

Model prediction of frost tolerance as related to winter survival of wheat in Finnish field trials

“…Snow cover is usually considered as beneficial, or even necessary, for winter survival, as it protects plants from being exposed to lethally low temperatures (Belanger et al 2002). Results from Bergjord et al (2008) do, however, indicate that a long-lasting snow cover might also have an exhausting effect, causing a reduction of the plants' frost tolerance, especially if the soil is unfrozen.…”

International Joint Commission

“…A reduction in the proportion of total precipitation that falls as snow has hydrologic implications; there is less storage of precipitation in snowcover and more runoff from rainfall occurs in winter. Less snow, and winter rainfall and ice formation can stress forage crops through frost heaving and ice encasement (Bélanger et al, 2002).…”

Climate change and winter damage to fruit trees in eastern Canada

“…characteristics and predominant crops (Bélanger et al 2001(Bélanger et al , 2002. Sixty-nine weather stations were selected, based on their representativeness of the agricultural regions and data availability (Fig.…”

“…Compared to the 1961 to 1990 period, the mean daily winter temperature (Nov. 01 to Apr. 30) would be 1.9°C higher by 2010 to 2039 and 3.3°C higher by 2040 to 2069 (Bélanger et al 2001(Bélanger et al , 2002.…”

“…Under current conditions, snow cover protects roots against extreme low freezing temperatures but winter injury to roots may occur in the future if there is insufficient protection from low air temperatures by snow. Bélanger et al (2001Bélanger et al ( , 2002 estimated that the number of days with potential occurrence of sub-freezing air temperatures (-15°C) in absence of a protective snow cover will increase from a current average of 12 to 28 d by 2040 to 2069 in eastern Canada. The exposure of fruit tree roots to potentially killing low temperatures will therefore increase and likely result in greater damage than under the current climate, especially if more tender rootstocks are introduced.…”