In the cold winter, the damage caused by freezing damage is very large, especially the temperature of the soil is greatly reduced or the sudden change of weather. If you want to protect your crop, you must take precautions in advance.

I. Effects of freezing damage on the growth and development of cucumber

The temperature suddenly drops, and the top of the stems of the plants in the front of the greenhouse and the tops of the young melons and the adjacent stems of the plants are water-stained. After one or two days, 80% to 90% of the tops of the stems are about 5 cm long and the stems are changed. Yellow, green and dry; part of the flower fell off; tender leaves appeared shrinkage; most of the plants were frozen to death, leaves, tender stems and tender fruit were water-stained. After about 10 days of returning to normal climatic conditions, the cucumber can fully recover. After that, the young stems under the top of the green bark continued to elongate, the melons grew rapidly, and the middle and lower side branches and the melons appeared, which seriously affected the time and yield of the melons.

Second, the cause of freezing damage

1. The investigation of low temperature and low temperature duration found that the lower the temperature drops, the longer the low temperature time continues, and the heavier the freezing damage of cucumber; the lighter the opposite.

2. Sudden cooling and weather conditions after sudden damage, the temperature suddenly drops sharply, and the freezing damage is heavy; if the temperature gradually decreases, the freezing damage is light. If it meets fine weather after low temperature, it will increase the freezing damage; on the contrary, after cloudy weather, the temperature will gradually rise, which will help the damaged cucumber gradually return to normal physiological vitality, and the cold and freezing damage will be light.

3. The impact of greenhouse microclimate Because the front corner of the solar greenhouse is a low temperature area, the cover is thin, so the front is seriously damaged, and most of the stem ends and the tender melon are frozen to death.

Third, preventive measures for freezing damage

1. Using grafted seedlings, the wilting rate of un-grafted plants in the same greenhouse is more than 10%, and the grafted plants are only about 1%. This is because grafted seedling rootstocks have strong cold resistance.

2. Before proper watering and fertilizing, the greenhouse cucumber is vulnerable to cold currents. It is necessary to apply less nitrogen fertilizer and control watering so as not to cause a longevity. 3 days before the cold current, do not water, otherwise it will cause the ground temperature to decrease, so that the root activity will be weakened, which will increase the freezing damage.

3. Fumigation and cold prevention When the cold current comes, some straw smoke is emitted every 2 hours, which can reduce the freezing damage. But the amount of smoke can not be too large.

4. Avoid excessive temperature after the low temperature. When the weather is clear, gradually open the grasshopper to avoid the sharp rise of temperature. If the temperature rises faster, then the temperature of the land is still very low, the root water is weak and the leaf transpiration is accelerated, causing damage to the water balance in the plant, causing physiological drought, resulting in severe freezing and causing top deadness.

4. Remedial measures for freezing damage

1. Strengthen the management of fertilizer and water to prevent the premature senescence of leaves. After the stems are dry, the management of fertilizer and water should be strengthened. In sunny weather, the room temperature is about 28 °C during the daytime, and the temperature is not lower than 12 °C at night, once a week under the membrane, combined with watering 667. Square meter of ammonium bicarbonate 20 kg.

2. After the pruning returns to normal growth, the nutrient level is relatively sufficient, and the side branches and the squash are produced in large quantities. However, the melons on the side branches have poor commercial properties, and the main vines of the plants have a certain length. Therefore, the growth of the lateral branches depends on the growth of 1 to 3 leaves, in order to form a peak season of more than one month.

3. After 50 days of freezing and cultivating other vegetables, the yield was very low and the plants began to decline. Tomatoes or kidney beans can be planted in the greenhouse, and the cucumbers are extracted after 40 days, and the yield is good.

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