CHANGES IN SURVIVAL OF WINTER CEREALS DUE TO ICE COVER AND OTHER SIMULATED WINTER CONDITIONS

Abstract
The survival of winter cereal cultivars of contrasting cold hardiness was determined after various modifications of the winter environment at two locations in 3 yr at Ottawa, Ontario. Artificially produced ice covers reduced survival in all cases, and the severest damage was associated with high soil moisture at the time of ice formation. Maintenance of soil temperatures close to zero by replacement of an insulating snow cover over ice increased average survival by about 10% compared with non-insulated plots. Naturally formed ice covers were less damaging than those artificially produced, and in one case formation of an ice cover protected plants from very low air temperatures, resulting in greater survival than in control plots. Total removal of snow in January was severely damaging, while accumulation of snow at a snowfence allowed increased survival of all cultivars. The correlation between cold hardiness and survival in ice treatments was significant, but one wheat (Triticum aestivum L.) cultivar showed better survival than comparable wheats in a number of ice-stressed treatments, while not showing superiority in unstressed or controlled environment conditions.