Improve the structure of the greenhouse. 1, building materials. The best conditions to use the galvanized steel canopy, Shouguang string-style greenhouses, shed 8 with galvanized iron wire tension, not only saving building materials, but also reduce the shading, it is worth promoting. 2, greenhouse orientation and shed face angle. It should be adjusted according to the greenhouse use time, production purpose and crop light conditions. In plastic greenhouses mainly cultivated in the spring and autumn, the shed angles can be smaller (15 or so), and the sheds are laid flat so that the transmitted light is evenly distributed and evenly distributed. In winter, the shed angle is larger (around 25). The shed was arched to facilitate lighting. 3. Shed width and back slope width. With a reasonable planting. When sowing seeds, the seeds are moved in the same direction. When transplanting, the cotyledons are arranged in parallel, and the specifications are strictly regulated so that the plants grow neatly and the shading between the plants is reduced as much as possible. The east and the west were planted in the east and the west, and the north and the south were used in the winter and spring to make the plants evenly distributed. In addition, the strengthening of cultivation and management is also conducive to improving the light conditions in the shed; according to reports, the use of the cucumber row in the front row to the south, the middle row upright, the rear row to the north, can increase the light utilization rate of about 10%. Keep the film clean. According to observations, a layer of water droplets adhered to the shed film can reduce the light transmittance by 20% to 30%. After the new film is used for 2 days, 10 days and 15 days, the light in the shed can be weakened by 14% in turn as a result of the contaminated dust. %, 28%. Therefore, the water droplets and dust on the shed film should be cleaned and cleaned frequently; the snow should be removed promptly after snow, in order to increase the transparency and the amount of light. In addition, outside the greenhouse covered with grass and other warm materials, under the premise of not significantly affecting the temperature of the shed, the appropriate early release of the late cover, to ensure the lighting area, extend the lighting time; greenhouse after the release of humidity for half an hour after sunrise , Can reduce the surface of the water droplets, which can also increase the light transmittance. Artificial light. In the winter season or in a plastic greenhouse with insufficient sunlight, artificial light supplement is particularly important, but due to the high cost, there is still difficulty in large-scale promotion, and it can be used as an emergency measure to improve lighting conditions in the shed. Specific requirements and practices are: 1, fill light intensity. Artificial fill light, requires light intensity to be large, l ~ 3 thousand lux is appropriate; 2, light source. Studies have shown that crops have the strongest absorption of red light and blue-violet light, so it is better to use fluorescent lights, high pressure mercury lamps, and arc xenon lamps. Light source intensity: 40 watts of three fluorescent lamps together, from the seedlings 45 cm high irradiation, light intensity of 3,000 to 3.5 kilograms, 100 watts of high-pressure mercury lamp 80 cm from the seedlings, the light intensity of 0.8 to 1 Thousand lux; 3, fill light time. Winter fill light should be carried out after sunrise, usually 2 hours to 3 hours a day, the light intensity increases after the shed to stop; rainy weather can fill light all day. Promote the use of aluminum film reflectors. The use of polyester aluminized film spliced ​​into 2 meters wide, 3 meters long reflective screen, hanging in the plastic post after the upper end of the column, hanging down to the ground. In this way, the ground can be increased by 40% to 43%, the greenhouse temperature can be increased by 3°C to 4°C, the ground temperature can be increased by 1.8°C to 2.9°C, the cucumber production can be increased by 20% to 25%, the tomato yield can be increased by 41.8% to 58.1%, and the quality can be improved. improve. In addition, the laying of silver gray film or aluminum foil on the ground can also increase the light intensity between the plants, so that the vegetables and vegetables can be well colored and prevent the premature decay of the lower leaves.
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