Prevention and Control measures of Fertilizer damage and High temperature damage of vegetables in greenhouse

In the vegetable greenhouse planting technology, fertilizer damage and high temperature damage are important factors affecting the yield, quality and benefit of vegetables, the following are the necessary control methods.

First, how to prevent and control fertilizer damage

1. Apply fertilizer deeply. Chemical fertilizer should be applied deeply or dissolved in water.

2. Appropriate amount of fertilizer. Because of less fertilizer loss in the greenhouse, its application amount should be lower than that of vegetables in the open field.

3. Mature application of organic fertilizer. In particular, fence fertilizer and human and animal feces and urine must be fully ripened and fermented.

4. change your breath at the right time. Ventilation should be strengthened after application, and a certain amount of ventilation should be maintained at night, so as to prevent harmful gases from accumulating in the greenhouse and toxic to vegetables during fertilizer decomposition.

5. The distance of fertilization should be suitable. Urea and other quick-acting fertilizers should not be applied near the roots to prevent root burning. When leaf fertilizer is applied, the appropriate concentration is 0.5% rel 1%.

6. The application amount should not be too large. No matter topdressing or foliar spraying chemical fertilizer, the amount must be appropriate.

Second, how to prevent and control the harm of high temperature

1. Strengthen ventilation. Adjust the air in the greenhouse to make the air fresh and remove all harmful gases in the greenhouse. The outside temperature rises to about 18 ℃ and gradually ventilates.

2. Control the appropriate temperature. The temperature in the greenhouse can be kept at 20-25 ℃ during the day and 15-18 ℃ at night. Temperature control can be combined with ventilation, water spraying and other measures.

3. Replenish water in time. When the greenhouse soil is short of water, we should replenish the water in time and adjust the temperature with water to reduce the harm of high temperature.

Third, how to prevent and control frost injury

1. Irrigation and heat preservation. Irrigation can increase the soil heat capacity, prevent the soil temperature from falling, stabilize the near-surface air temperature, help the air temperature rise steadily, and restore the function of frozen vegetable tissue.

2. Keep the wind and cool down. After the vegetables in the greenhouse are frozen, do not immediately close the greenhouse to raise temperature, but can only let the air cool down, so as to make the temperature in the greenhouse rise slowly and avoid the sudden rise in temperature to cause the necrosis of frozen tissue.

3. Artificial water spraying. Water spraying can increase the air temperature in the greenhouse, stabilize the greenhouse temperature, inhibit the evaporation of water from the frozen tissue, and promote the tissue to absorb water.

4. Cut off the dead branches. Cut off the frozen stems and leaves in time to avoid tissue mildew and disease.

5. Set up a shed for shade. Setting up a shed for shade in the greenhouse can prevent frozen vegetables from direct sunlight and make frozen tissue lose water.

6. Replenish fertilizer. After slowing down the seedlings of frozen plants, to apply quick-acting fertilizer, foliar spraying can be done with 2% urea or 0.2% potassium dihydrogen phosphate.

7. Prevention and control of diseases and pests. After the plant is frozen, diseases and insect pests are easy to swoop in, so some protective agents and insecticides for disease prevention and control should be applied in time.

IV. How to prevent and control climate disasters

Energy-saving solar greenhouse greenhouse vegetable production in the disastrous weather are: continuous overcast snow (rain, fog) days, low temperature and little sunshine, snowstorm, sandstorm and so on. Although the probability of this kind of weather is very low, once encountered, it will be extremely disadvantageous to production, and the following measures can be taken in production.

1. Optimize the structure and improve the effect of heat preservation.

2. give priority to "protection" to improve the ability of plant tolerance. In winter management, the temperature should be kept low and conservative measures should be taken to ensure that the plant can survive the winter safely. Keep 25-28 ℃ during the day and 10-14 ℃ at night. Spraying 1 ∶ of sugar and nitrogen solution, or adding 0.5% glucose and 0.3% potassium dihydrogen phosphate can not only improve resistance, but also improve plant resistance to downy mildew.

3. In the continuous overcast, rainy and snowy weather, more light is seen on the basis of heat preservation, receiving scattered light from cloudy days, while keeping the temperature of the solar greenhouse unchanged. Heat should be increased before the temperature drops to the point where growth is about to be harmed to ensure that the plant is not harmed by freezing. Heat up to the lowest biological temperature of 13-15 ℃, not too high, in case respiratory consumption increases.

4. Return home after rainy and snowy days. When it clears up after a cloudy and snowy day, the plant wilts due to the imbalance of water in the plant, the growth point is damaged in light, and the vegetables in the whole greenhouse die when it is heavy. At this time, attention should be paid. The method is to uncover it early after the day turns sunny, so that it can see the light in the early morning sun and gradually adapt to it. If it is found that the plant is wilting, it should be covered in time, and then opened after the plant is restored. If wilting occurs, it should also be covered again. This can be repeated several times, and it can also be combined with foliar spray to adjust the water balance.