Semi-winter wheat varieties have some tolerance in resistance to low temperatures, but their cold tolerance is slightly weaker than that of strong winter wheat varieties. According to the data, the extreme low temperature of strong winter wheat varieties is minus 147℃~16.4, while the extreme low temperature of semi-winter wheat varieties is not known, which is a problem that needs to be further improved. However, based on past observations and experiments, we can draw some preliminary conclusions.
The effect of short low temperature on semi-winter wheat varieties was relatively small. The lowest minus 26 in Shijiazhuang, Hebei5 and Xiajin County, Dezhou, Shandong Province, with a minimum of minus 222 For example, these short-lived, short-lived extreme cold temperatures do not cause much damage to wheat. This is because in this case, the temperature decreases and rises rapidly, and the plant is not exposed to the influence of low temperatures for a long time.
However, when faced with the challenge of sustained low temperatures, the situation is different. In recent years, we have witnessed some rare extreme low temperatures, especially in 2023"Four extremes", which brought huge frost damage pressure to semi-winter wheat varieties. These extreme low temperatures are characterized by unusually low minimum temperatures and long durations, as well as low maximum temperatures. In this case, it is difficult for most varieties to survive.
According to Modern Wheat Production Techniques, semi-winter wheat varieties generally tolerate low temperatures for not too long, such as:"U-shaped cooling"The lowest temperature can reach minus 15. However, Mr. Song Yinming mentioned that in order to resist prolonged low temperatures (lasting more than 5 days) relatively safely, semi-winter wheat varieties require a minimum temperature of not less than minus 8. Under such temperature conditions, wheat varieties can grow and develop relatively safely.
Based on the analysis of the above factors, we can conclude that 100% of semi-winter wheat varieties in 2023-2024 are likely to be affected by frost damage. Of course, this is only a rough estimate, and the exact degree of frost damage will be affected by other factors, such as the thickness of the snowfall. The thicker the snowfall, the less frost damage the wheat varieties will suffer.
In the face of the threat of frost damage, we need to take some measures to minimize losses and risks. Here are some suggestions for managing and selecting wheat varieties:
1.Corresponding management measures are taken for different varieties. For varieties with poor frost resistance, we should consider eliminating them and choosing those varieties with better frost resistance.
2.If a variety has suffered severe frost damage, it is necessary to determine whether it is within the approved area. If not, you can claim directly. The success rate of claims is high.
3.For wheat varieties with poor purity in the field, even if they are beautifully packaged, they can be used if the frost damage is heavy"Inferior seeds"or"Fake seeds"for claims.
When choosing a wheat variety, a number of factors should be taken into account. First of all, in addition to frost resistance, wheat varieties should also have drought resistance, disease resistance, lodging resistance, and resistance"Withered white spikes"and resistance to hot and dry air. Secondly, the indicators of 1000-grain weight and spike per mu are also important reference factors when selecting varieties. The higher the 1000-grain weight, the more roots the seeds have, and the stronger the resistance to frost and drought. Varieties with more ears per mu and stable tend to have better comprehensive resistance.
As climate change intensifies, the impact of frost damage on crops is becoming more and more concerning. The growth of semi-winter wheat varieties in the cold winter environment is more challenging, but through proper management and selection of high-quality varieties, we can reduce the risk of frost damage. In the future of crop planting, we need to pay more attention to variety selection and scientific management, and strive to improve the cold resistance of crops to cope with the increasingly severe challenges of frost damage.