What harm does high temperature in summer cause to crops? How should it be prevented and controlled?

The hazards of high temperature to crops:

1. High temperatures deactivate the chlorophyll in plants and reduce the rate of photosynthesis.

2. High temperatures accelerate the evaporation of water within plants. A large amount of water is used for transpiration and heat dissipation, disrupting the water balance within plants. This affects the growth period of crops, causing them to mature and age prematurely, and thus impacting the yield.

3. High temperatures can affect flower bud differentiation and pollen activity, leading to difficult or uneven pollination of female flowers and an increase in deformed fruits.

High-temperature prevention and control

1. Timely supplementation of nutrients and timely spraying of calcium chloride, zinc sulfate or dipotassium hydrogen phosphate solution when the temperature is high can increase the thermal stability of the biofilm and enhance the plant’s resistance to heat. Introducing bioactive substances such as vitamins, biological hormones and agonists to plants can prevent biochemical damage to plants caused by high temperatures.

2. Water can be used to cool down. During the hot summer and autumn seasons, timely irrigation can improve the microclimate in the fields, lowering the temperature by 1 to 3 degrees Celsius and reducing the direct damage of high temperatures to flower containers and photosynthetic organs. When the sunlight is too strong and the temperature inside the greenhouse rises rapidly above the suitable temperature for crop growth, and the temperature difference between the inside and outside of the greenhouse is too large to be ventilated and cooled, or even after ventilation, the temperature still cannot be reduced to the required level, partial shading measures can be taken. That is, straw curtains can be covered from a distance, or curtains with larger gaps such as straw curtains and bamboo curtains can be covered.

3. Avoid sowing too late and strengthen the management of water and fertilizer in the early stage to promote lush branches and leaves, reduce sun exposure, strengthen seedlings, and enhance the ability to withstand high temperatures. This can prevent the situation where female flowers are difficult to pollinate or pollinate unevenly due to high temperatures, and the number of deformed fruits increases.