How to improve the lighting efficiency of greenhouse?

The lighting efficiency of greenhouse is very important, which is related to the growth of crops. After all, sunlight is a necessary condition for crop growth. Once photosynthesis is lacking, crops cannot grow healthily and healthily. So how can the lighting efficiency of the greenhouse be improved?

1. Improve the structure of the greenhouse.

① Building materials. The shed surface is tightened with No. 8 galvanized iron wire, which not only saves building materials but also reduces shading, and has great promotion value. Use drip free film for greenhouse film; Polyethylene film is preferred for ordinary films. In addition, applying white coating to building materials and walls can increase reflected light and extend their service life; Increasing the height of the greenhouse appropriately can also improve the lighting conditions inside the greenhouse.

② The orientation and angle of the greenhouse. Adjustments should be made based on the usage time of the greenhouse, production purpose, and the requirements of crops for lighting conditions. A plastic greenhouse mainly cultivated in spring and autumn can have a smaller surface angle (around 15 °), and the greenhouse surface should be leveled to ensure equal distance and uniform distribution of transmitted light; In winter, it is required to have a larger angle of the shed surface (around 25 °), and the shed surface should be arched to facilitate lighting The width of the shed and the width of the rear slope. Winter production, with a shed width of 6-6.5 meters and a horizontal distance of 0.8-1 meters on the back slope to facilitate lighting and insulation; Spring and autumn production, with a shed width of 8-9 meters and a horizontal distance of 0.5-0.7 meters from the back slope or with the back slope removed.

2. Reasonable layout.

When planting different types of vegetables in greenhouses, the principle of "high in the north and low in the south" should be followed to ensure that the plants are arranged in an orderly manner and minimize mutual obstruction. Transplant the same type of vegetable, striving for consistent seedling size to ensure neat plant growth and reduce inter plant shading. At the same time, it is better to use north-south orientation for border planting to receive sunlight as much as possible. In addition, strengthening cultivation management is also beneficial for improving the lighting conditions inside the greenhouse; According to reports, the cucumber rack adopts a method of tilting the front row towards the south, upright the middle row, and tilting the back row towards the north, which can increase the light utilization rate by about 10%.

3. Keep the greenhouse film clean.

The water droplets and dust on the greenhouse film have a significant impact on the lighting conditions inside the greenhouse. According to observations, attaching a layer of water droplets to the greenhouse film can reduce the transmittance by 20 to 30%; After using the new film for 2 days, 10 days, and 15 days, the light inside the shed can be reduced by 14%, 25%, and 28% due to dust contamination. Therefore, water droplets and dust on the greenhouse film should be regularly cleaned and cleaned; Clear the snow in a timely manner after snowfall to increase transparency and light intake. In addition, the insulation materials such as straw sheets covered outside the greenhouse should be uncovered early and covered late without significantly affecting the temperature inside the greenhouse Daylighting area, extending lighting time; The greenhouse can reduce water droplets on the film surface and thus increase light transmittance by allowing air and humidity to be drained for half an hour after sunrise.

4. Reasonably lift the straw curtain.

On the premise of doing a good job in insulation work, removing the grass curtains and delaying the cover curtains used for insulation in advance can extend the lighting time and increase the amount of sunlight. Generally, the curtain is lifted 0.5 to 1 hour after sunrise and then half an hour before sunset. Especially in foggy and rainy weather, it is necessary to lift the curtain appropriately to fully utilize the scattered light of the sun.

5. Select drip free film.

Several performance active agents are added to the production of drip free films, which greatly reduces the affinity between water molecules and the film. Water droplets flow into the ground along the film surface without generating any water droplets. Choosing a drip free film buckle shed can increase the light intensity inside the shed and increase the temperature of the shed.

6. Set up reflective curtains.

Spliced with polyester aluminized film, a reflective curtain with a width of 2 meters and a length of 3 meters is hung on the upper end of the rear column of the plastic greenhouse, with the lower edge hanging to the ground. In this way, the ground can be brightened by 40% to 43%, the greenhouse temperature can be increased by 3-4 ℃, and the ground temperature can be increased by 1.8-2.9 ℃; And there has been some improvement in quality. In addition, laying silver or aluminum foil on the ground can also increase the light intensity between plants, make fruits and vegetables well colored, and prevent premature aging of the lower leaves.

7. Organize the plants well.

Timely field management such as pruning, branching, binding vines, and removing old leaves is beneficial for the ventilation and light transmission conditions inside the greenhouse.

8. The buckle should be tightened and flattened without wrinkles.

Generally speaking, it is easy to tighten the buckle before and after noon.

9. The lifting rope should be colorless and transparent.

This can make the most of the light as much as possible.

10. Artificial fill light.

In the deep winter season or in plastic greenhouses with insufficient sunlight, artificial light replenishment is particularly important. The specific requirements and methods are: ① Light replenishment intensity. Artificial light supplementation requires a high light intensity, preferably 1-3 kilolux; ② Light source. Research has shown that crops have a strong ability to absorb red and blue purple light, so the light source is a combination of three fluorescent lamps with a light source intensity of 40 watts, shining at a height of 45 centimeters from the seedlings, with a light intensity of 3.0-3.5 kilolux. A high-pressure mercury lamp with a light source intensity of 100 watts is 80 centimeters from the seedlings, with a light intensity of 0.8-1 kilolux Fill time. Winter light replenishment should be carried out after sunrise, usually 2-3 hours per day, and stopped after the light intensity inside the greenhouse increases; Cloudy and rainy weather can provide light throughout the day.