With the advent of the "three days", the farmland has also opened a "barbecue mode", and the normal growth and development of many crops is affected, causing the so-called "heatstroke", that is, high temperature heat damage.
1. The effect of high temperature on crop growth and development. The effect of high temperature on crop growth and development is multi-faceted: 1 rice (especially hybrid rice), if it encounters high temperature after flowering cracking of anther, the pollen quickly loses its vitality. When the temperature is higher than 35 °C, the pollen tube tip is broken a lot. Loss of fertilization ability, the formation of a large number of empty white shells, commonly known as "high temperature is not true." When high temperature is encountered during the filling stage, which affects the accumulation of dry matter, the 1000-grain weight can be reduced by 0.42~3.24 grams, commonly known as “high temperature ripeningâ€. 2 If the cotton encounters a high temperature above 30 °C in the bud stage, the top bud will grow too fast, the lateral bud growth will be inhibited, and the bud speed will be significantly slowed down. When the buds and bolts encounter a high temperature above 32 °C, the buds will fall off significantly; it is observed that for every 1 °C increase in temperature, the shedding rate increases by 0.66% to 2.2%. 3 other crops such as corn, when the temperature is higher than 35 ° C, the air humidity is close to 30%, 1 to 2 hours after loosening, the pollen will quickly dry up and lose the germination power; when the soybean meets the high temperature above 33 °C during flowering, there is no flower. Open; when the potato encounters a temperature above 29 °C, the tubers stop expanding.
2. The main countermeasures. 1 cool down with water. Timely irrigation can improve the microclimate conditions in the field and reduce the temperature by 1 °C ~ 3 °C, thus reducing the direct damage to the flower and photosynthetic organs of the high temperature; when encountering the high temperature of about 35 °C in the early rice filling period, timely watering the field, at night Discharge, can avoid or reduce the "high temperature ripening". Spraying the cool water directly on the stems and leaves of the crop through a sprinkler irrigation facility or a sprayer also has a cooling effect, and the cooling temperature is generally about 1 °C. 2 artificial assisted pollination. During the high temperature and drought period, the natural pollination ability of crops decreased, and artificial pollination of cross-pollination crops such as corn and sorghum could reduce the influence of high temperature on the pollination and fertilization process of crops, and the seed setting rate would be increased by 5%-8% compared with natural pollination. 3 external top dressing. In the high temperature season, urea, potassium dihydrogen phosphate solution or superphosphate and grass ash leaching solution can be used for foliar spray multiple times, which is beneficial to both cooling and humidification, and can supplement the water and nutrients necessary for crop growth and development. Pay attention to reducing the spray concentration and increasing the water consumption.
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