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(I) Light intensity:
The intensity of light in the facility, the integrator shows: generally weaker than natural light, because natural light can enter the facility through the transparent roof covering material, this process will be due to the absorption, reflection of the covering material, and the condensation of the inner surface of the covering material. Water droplets refract, absorb, etc. and reduce light transmittance. Especially in the cold winter, spring or cloudy snow days, the light transmittance is only 50% of the natural light. If the transparent cover material is not clean, the use of a long time and dust, aging and other factors, the rate is even less than 50% of the natural light intensity.
(b) Illumination hours:
The number of hours of illumination in a facility refers to the length of light received, which varies according to the type of facility. Plastic greenhouses and large arrival ridge greenhouses, due to full light, no outside cover, the number of hours of exposure and facilities in the facility is basically the same. The measurement data of the integrator shows that the light hours in the single-roof greenhouse are shorter than the exposed ground, because in the cold season, in order to prevent the cold, the uncovering time of the covered mat and grasshopper directly affects the hours of light received in the facility. In the cold winter or early spring, it is generally uncovered after sunrise, and it is necessary to cover it before sunset or just after sunset. When the crop is light-received for 7 days during the first day, it is far from meeting the sunshine hours of horticultural crops. Demand.
(c) Light quality:
The light composition (light quality) in the facility is also different from that of natural light, and is mainly related to the nature of the transparent covering material. The major agricultural facilities in China are mostly plastic film covering materials, and the transmitted light quality is directly related to the composition and color of the film. relationship. The characteristics of glasshouses and rigid plastic sheets also affect the quality of light in the facility. The cultivation of sunlight in the open field directly shines on the crop. The composition of the light is the same, and there is no difference in light quality.
(d) Light distribution:
The cultivation of open field crops is uniform under natural light, but not in facilities. For example, according to the data displayed by the integrator, the back roof of a single-roof greenhouse and the walls on the east, west and north sides are not far away, and there are often shades near or below. Under the transparent roof facing south, light illumination is superior to the north. It has been determined that the yields of cucumber in the front, middle and rear pods of the greenhouse cultivation bed differ greatly. The light conditions in the front row are good, and the yield is the highest, followed by Chinese wolfberry and the rear row, reflecting the uneven distribution of light. The different elevation angles behind a single roof greenhouse can also affect how much light transmittance varies. The ground of different parts of the facility is different from the roof, and the lighting conditions are also different. The uneven distribution of light within the facility makes the growth of horticultural crops inconsistent.
Four aspects of facility lighting environment
The illumination environment in the facility is different from the open field. Because it is an artificially constructed protection facility, the lighting conditions in the facility are affected by various factors such as the building orientation, the facility structure, the size and shape of the translucent roof, the characteristics of the covering material, and the degree of cleanliness. . In addition to light intensity, light hours, light composition (light quality), etc., the light environment in agricultural facilities also needs to consider the influence of light distribution on its growth and development. The four characteristics of the lighting environment.
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