Harm of Cold Dew Wind to Rice and its Preventive measures

Cold dew wind refers to the period of heading and flowering of late rice in the south, when the daily average temperature drops below 22 ℃ for three or more days in a row, resulting in empty shell and shrunken grains of late rice, resulting in a disastrous weather that reduces production. Because the cooling is generally accompanied by northerly winds, it is commonly known locally as cold dew wind.

The harm of cold dew wind: the low temperature in the heading and flowering stage of late rice will make the pollen grains unable to mature and fertilize normally, resulting in empty grains; under the condition of low temperature, the heading speed slows down, the heading stage is prolonged, and the spikelets can not open normally, disperse powder, fertilize, block the extension of ovary, etc., resulting in sterility and a significant increase in empty grains. In addition, if there is an obvious low temperature in the early filling stage, the filling process will be delayed or stopped, resulting in shrunken grains, the plant nutritional physiology of rice will also be inhibited, and some even appear the phenomenon that the grain is not full and the seedlings have withered first.

Defensive measures:

1. Reasonable collocation of varieties. The reasonable collocation of early and late rice varieties according to the growth period of early and late rice varieties can ensure the safe panicle of late rice before the cold dew wind.

2. Select resistant varieties. There are great differences among varieties, so high-yield varieties with low temperature resistance should be selected.

3. Reasonable sowing date, training strong seedling, shallow planting and shallow irrigation, scientific water management and fertilization.

4. Adjust the microclimate and reduce the harm; when the cold wave comes, the deep water at night is 7-10CM, and the water temperature is 2-3 ℃ higher than the mud temperature during the day.

5. Apply '920' and 'grain satiety' to speed up heading.