When is the critical period of wheat dry-hot wind injury?

The critical period of wheat dry-hot wind damage is filling stage.

Dry-hot wind is one of the main meteorological disasters in northern China, which usually occurs in May and June, which can seriously destroy the photosynthesis and water balance of crops and cause great losses to crop growth and yield in a short time. In the middle and late May, the northern wheat entered the stage of filling and milk ripening, and the dry and hot wind would pose a great threat to the wheat yield and harvest.

To prevent wheat from being harmed by dry-hot wind, we should first pay attention to watering slurry water and wheat yellow water, increase the relative humidity of wheat field, reduce the ground temperature and improve the microclimate in the field. At the early stage of grouting, slurry water should be poured, and wheat yellow water should be poured from the peak of milk ripening to the early stage of wax ripening.

Pay attention to the weather forecast and learn from farmers' experience of "windy and rainy, no irrigation at noon". Secondly, chemical agents such as petroleum accelerator, plant ash water, potassium dihydrogen phosphate, boron and sodium humate can be sprayed when dry-hot wind appears, so as to enhance the water-holding capacity of leaves and reduce transpiration intensity, thus reducing the harm of dry-hot wind and achieving good effect of preventing dry-hot wind from increasing wheat yield.

Causes of dry-hot wind

Due to the different natural characteristics of different places, the causes of dry and hot wind are also different. In the early summer of each year, the climate in China's inland areas is hot, the rainfall is scarce, the temperature rises strongly, and the air pressure drops rapidly, forming a strong continental thermal depression.

Around this hot low pressure, the pressure gradient increases with the increase of air mass temperature, so the dry-hot airflow rotates around the hot low pressure to form dry-hot wind, which is dry-hot wind. Strong dry and hot wind will do harm to local wheat, cotton and melons.

Mongolia with dry climate, west of Hetao in China, Xinjiang and Gansu are the areas that often produce continental thermal depression. After the heat and low pressure leave the source, it will become drier and drier along the way through the dry and hot Gobi desert, and the dry and hot wind will become stronger.

The climate of Tarim Basin, located in the center of Eurasia, is extremely dry, and the "foehn wind" generated by the strong cold front crossing Tianshan and Pamirs often causes a wide range of dry and hot winds in the local area.