How to do a good job in the greenhouse in the spring air release work to ensure the safety of greenhouse shed it?

First, the degree of crown is different, the outlet size is not the same

The size of spring tuyere cannot be completely defined by a certain data. Because the structure of greenhouses is different, the time and speed of cooling are also different. In large greenhouses with a high degree of crowning, the hot air flow is easily discharged along the upper part of the greenhouse film because of the suitable crowning, and even if the air outlet is small, a good air release effect can be achieved. In the low and old sheds with longer planting dates, the greenhouses have a smaller degree of arch and the sheds are flatter. The hot air flow in the sheds is discharged from the air outlets at a slow speed, and the temperature inside the sheds is high. Under normal circumstances, such a shed will open the top vent to 40 cm wide, and it will have the same effect as a 30 cm high wind outlet with a high height and a large crown.

Second, the wind direction is different, the size of the air outlet on both sides of the greenhouse is not the same

When the west wind blows, the vegetables on the west side of the greenhouse are blocked by the gables. The heat in the shed is relatively less, and the temperature is higher. When the air is released, attention should be paid to increasing the air outlet on the west side of the greenhouse and putting it on the east side. The tuyere is reduced. When the east wind is blown, the vents on the east side of the greenhouse should also be widened. When the temperature in the afternoon shed falls, if it is a westerly wind, the ventilation outlet on the east side of the shed should be closed first, and the ventilation outlet on the west side of the shed should be left with a gap. When the south wind or the north wind blows, the vents on both sides of the greenhouse can be opened to the same size. Only according to the difference in wind direction, the size of the air outlets on both sides of the greenhouse can be properly adjusted to ensure that the greenhouse temperature is consistent and promote the simultaneous growth of vegetables.

Third, the spring should pay attention to sub-ventilation

After opening the shed for 1 hour in the morning, a small breeze of about 3-5 centimeters was put on the upper air outlet to remove moisture from the shed and supplement the carbon dioxide in the shed to supplement the raw materials for photosynthesis. When the shelf temperature rises above 28°C, the air outlet shall be gradually opened, and the temperature within the shelf shall not exceed 33°C (for cucumber and loofah etc.).

Fourth, the spring breeze, vents pay attention to wind

Increase the density of the air release rope, and it is better to use a wide cloth with large friction. When the cloth is used to fix the shed film, the friction force is large, and the slip knot is not easily blown loose by strong wind. Many vegetable plots are convenient to use nylon ropes as windproof ropes, because the friction force is relatively small, and the vegetable grower should increase the density of the nylon release rope properly and fix it so that the tuyere is blown by the wind. At the same time, vegetable farmers should also pay attention to checking at any time in the windy weather to prevent loosening of the rope and closing of the tuyere.