How to prevent high temperature hazards when cultivating pitaya in greenhouse?

In summer and autumn, the temperature in the shed can reach 4-5℃, and pitaya will stop growing in the environment above 4℃, which will affect flower bud differentiation, and at the same time, high temperature and drought will also cause high incidence of various diseases. Therefore, in the high temperature environment in summer, a series of measures should be taken to reduce the harm of high temperature. After the end of the cold spring, the weather is getting warmer, so the shed can be opened appropriately. When the lowest temperature is 15 degrees, it is best to uncover all sheds, increase the ventilation in the park and reduce the temperature. In the month with the highest temperature, a sunshade net can be set outside or inside the shed to reduce the damage of strong light to fruit trees. In summer, greenhouses should be watered frequently and fertilized in small quantities for many times. Water and fertilizer can supplement nutrients and moisture, and at the same time reduce the temperature in the shed. Keep ventilation after pouring water and fertilizer, reduce the humidity in the hospital and prevent the outbreak of soot disease.

Choose a ruler with no pests and diseases, strong growth and full stems as the rootstock, and graft it in sunny days. Cut the pitaya stem into a plane with a knife, insert the scion, align it with the cambium, and tie it firmly with cotton thread. At 28-3℃, a large number of calli were formed at the wound joint for 4-5 days, and the color of scion was close to that of rootstock, indicating that its vascular bundle had healed and grafted successfully, and then it could be moved to the heel of seedbed for further culture. Greenhouse cultivation in hot summer or autumn will also encounter high temperature problems. In late autumn, winter and spring, the main measures to cool the greenhouse are ventilation and sunshade net covering, and the main methods to cool the greenhouse in summer are sunshade net covering, deep well irrigation and straw covering. It is particularly important to note that the maximum temperature in the greenhouse in summer and autumn should not exceed 33C.

sometimes several methods are used together in production. In greenhouse cultivation, because of the high temperature, it is very common to burn seedlings, so it must not be completely covered. When there are multiple layers of coverage, ventilation is usually carried out from the inside out, that is, the small and medium-sized shed is ventilated first, and then the greenhouse is ventilated; Generally speaking, there is no ventilation before seedlings are buried and plants are replanted. However, if the temperature in the shed is too high, the greenhouse can be ventilated, and the small and medium-sized shed is still closed. The ventilation position of the greenhouse should be leeward, usually the east side of the greenhouse should be ventilated first, and more attention should be paid to the wind direction in windy weather; Vents should be small and large; The time to start ventilation should depend on the weather conditions. Generally, when the temperature in the shed reaches or exceeds the temperature that the crops can bear, it is not suitable for ventilation, and it should be advanced appropriately.