What is the danger of dry hot air? How to deal with the dry heat of wheat

At the moment, the grain filling period of wheat is the key period for determining the 1000-grain weight of wheat. In recent days, the Central Meteorological Observatory has issued an orange warning of dry hot air continuously, which has sounded the siren of the wheat conservation and defense war. What is the dry hot wind? What effect will it have on the high yield of wheat? How to prevent it? Next, Xiaobian has carried out a series of combing to give you detailed answers. First let's take a look at the recent hot weather conditions:

Today, the high temperature yellow warning is released continuously! Many places will be included in the high temperature “baked test”! Today, the high temperature intensity and range will reach the strongest time of the process, North China, North Huanghuai, Central and Eastern Inner Mongolia, and the western part of Northeast China. In other places, it will accept high temperature “baked inspection” above 35°C. The highest temperature in some areas of Inner Mongolia and northern Henan is 37～39°C, and the southeastern part of Inner Mongolia can reach 40°C.

In the coming week, the average temperature in most of the northern winter wheat areas will be higher than normal, and the North China and other places will be 4 to 5 °C higher. By the 19th, Beijing, Tianjin, Hebei, Henan, Shanxi, and northern Shandong continued to be sunny and hot. The highest temperature was generally above 32 °C, the relative humidity of the air was small, and the wind in the afternoon was generally more than 3 m/s, plus the soil moisture deviation in some areas. In the winter wheat area, there will be “dry hot wind” weather.

Among them, from 18th to 19th, the highest temperature in the central and southern Hebei and parts of northern Henan can reach about 37 °C. In the near future, there will be moderate to heavy “dry hot wind” weather, which is unfavorable for winter wheat grain filling, which will lead to a decrease in the grain filling rate of winter wheat. Grain weight.

What is the danger of dry hot air?

In some areas of northern China, generally during the period of wheat grouting from May to July, the average temperature of the day is above 25 °C, the highest temperature is above 32 °C, the relative humidity of the air is less than 30%, and the wind speed is greater than 2~3 m/s, due to temperature. Significantly increased, the humidity decreased significantly, accompanied by a certain wind, the plant transpiration increased, the roots did not absorb water, it will make the winter wheat or spring wheat grouting speed so slow that the filling is insufficient and the grain weight is reduced.

If the maximum temperature is above 35 °C, the relative humidity is below 25%, and the wind speed is greater than 3 to 4 m/s, it will cause the grain to die and lead to severe production.

Dry hot wind is a kind of frequent meteorological disaster in the late growth stage of wheat. After wheat damage, it can generally reduce production by 5%-10%, and individual severe cases can reach more than 20%. After dry hot air, the water in the wheat is quickly consumed, which destroys pigments such as chlorophyll and hinders photosynthesis, so that the plants can quickly dry from bottom to top.

Now it is the period of wheat grain filling. If it encounters dry hot wind and wheat ears, it will not be able to grout. In advance, it will be “dry”, the grain will dry up, and the grain weight will drop, which will lead to severe wheat yield reduction. China's North China, Northwest China and Huanghuai areas have appeared during the late spring and early summer. They are generally divided into two types: high temperature and low humidity and hot and dry after rain.

Meteorological indicators for dry hot wind hazards

Winter wheat and spring wheat are different, and the regions are also inconsistent. Generally speaking, for high temperature and low humidity type: light dry hot air is the highest daily temperature greater than or equal to 29 to 34 ° C, and at 14 o'clock the wind speed is greater than or equal to 2 to 3 m / sec. The maximum dry air temperature is greater than or equal to 32 to 36 ° C. At 14 o'clock, the relative humidity is less than or equal to 20 to 30%. At 14 o'clock, the wind speed is greater than or equal to 2 to 4 m / sec. This is the main type of wheat in the northern part of China, which mainly causes the wheat dry tip, the wheat grain to be yellow, and the wheat to dry up, thus affecting the yield.

Hot and dry after the rain: There is a rainfall process within 10 days before the ripening of the wheat, and the temperature rises after the rain, and the highest temperature in the day is more than 30 °C within 2 to 3 days. This situation mainly causes the dry and dry conditions of wheat.

Preventive measures for dry and hot wind of wheat

1. Pour the grout water. After wheat blooms, it enters the stage of wheat filling. At this time, high temperature, drought and strong wind force the evaporation of air and soil water to increase. Pouring the grouting water can maintain proper soil moisture, increase air humidity, delay root premature aging, and enhance leaf photosynthetic The role of prevention or reduce the harm of dry hot air. Pay attention to the wind stop pouring, no wind and water. The grouting water should be poured at the initial stage of grouting.

2, skillfully poured wheat yellow water. About 10 days before the wheat matures, according to the wheat population, weather conditions, soil moisture, pouring a wheat yellow water before the dry hot air comes, can significantly improve the field microclimate conditions and reduce the dry hot wind hazard. The wheat yellow water is poured at the beginning of the wax ripening period.

3, foliar spray fertilizer. In the early stage of wheat flowering to filling, use 1% to 2% urea solution, 0.2% potassium dihydrogen phosphate solution (93% content of potassium dihydrogen phosphate for 1.5 yuan a small packet, a package of 100g, you can contact 13203809264 to buy) , 2% ~ 4% calcium perphosphate leaching solution or 15 ~ 20% straw ash leaching solution for foliar spray fertilizer, spraying 20 ~ 100 kg per acre, can accelerate the growth and development of wheat later, prevent or reduce the dry hot wind hazard.

4, foliar spray vinegar. In the early stage of wheat filling, spraying with 0.1% acetic acid or 1:800 vinegar solution can reduce the opening angle of the pores on the leaves, inhibit the transpiration, and improve the drought resistance and dry heat resistance of wheat plants.

5. The “one spray three prevention” in the later stage of wheat is one of the effective measures to prevent and mitigate the hazards such as pests and diseases, dry hot winds, etc. Therefore, it should be sprayed 2-3 times according to the occurrence of diseases and insect pests and weather changes, which can effectively increase the grain weight. Prevent dry hot air.

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