In the stage of heading and flowering, if the low temperatures occur earlier, the lower and longer, the damage will be more serious. If it is accompanied with high winds, rain, or excessively dry weather, then the harm will be aggravated. For example, in the coastal areas of southern China, when the cold air southward encounters a typhoon, there will be strong wind, heavy rain, storms or cloudy weather for several days running. It will influence the heading and flowering of the late rice, and cause mechanical damages with more severe harm.

2. Types of the Cold Dew wind according to the damage caused by the Cold Dew wind, the weather can be divided into two types. 1) The wet cold type: the meeting of cold air blowing southward with retreating warm-wet air leads to low temperatures and rainy weather. The results are low temperatures, rain and less sunshine. 2) Dry and cold type: the strong cold air southward brings northerly winds. The wind force is about 3 to 5. The air is dry, sun is bright and the temperature drops significantly. The characteristics are low temperature, dry air, strong wind and a great difference in temperature between day and night.

3. Classification of the Cold Dew Wind The classification of Cold Dew wind bases on the daily average temperature, daily minimum temperature, and rainy days. The classifications are dry-cold type and wet-cold type, and mild type and serious type for each.

4. Defense against Cold Dew wind Cold Dew wind is harmful to late double cropping rice, so active defense measures must be taken: 1) According to the Cold Dew wind law and the safe full heading period of double cropping rice (it is 80% that the double cropping rice would not be influenced by the wind), choose the right seeds. 2) Arrange the production process according to the forecast of the Cold Dew wind. 3) Select the low temperature resistance and high-yielding seeds. 4) Strengthen field management, fertilize intelligently, and irrigate scientifically. Enhance root activity and leaf assimilation capacity to make sure the plants grow well and improve their resistance to the cold. 5) Take the appropriate measures in agriculture to improve the field microclimate.

Source: China Weather Network

Translated by Zhang Min

Editor: Wen Yi