Greenhouse supplement light lamp, also called plant supplement light lamp, is according to the natural law of plant growth, according to the principle of plants using sunlight for photosynthesis, the use of light instead of sunlight to provide greenhouse plants with a light source needed for growth and development.
The principle ：
Light is closely related to the growth of crops. To maximize the capture of light energy and give full play to the potential of plant photosynthesis is directly related to the benefit of agricultural production. In recent years, due to the promotion of market demand, greenhouse greenhouses are widely used to produce out-of-season flowers, melons, fruits, vegetables, etc. Due to the short sunshine time in winter and spring, crops grow slowly and yield is low, so it is urgent to fill the light.
The direct threat to the production of protected land represented by solar greenhouse is as follows:
(1) when the light intensity is lower than its compensation point, the organic matter consumption is more than the accumulation, and the dry quality of the plant decreases, or even dies. Even under the condition of low light, the growth of the plant also showed weakness and showed paracentric growth.
(2) influence flowering and fruit. Fruits and melons have certain requirements on the light time and intensity. If the light time of watermelon is less than 11 hours, all the young fruits will fall off. Light intensity requirements of medium vegetables such as peas, beans, celery, radish, Onions, etc. The light intensity of vegetables, such as lettuce, spinach, garland chrysanthemum and ginger, is relatively low. Even in sunny days, the light intensity of aubergines produced in solar greenhouses in Beijing could not reach the light saturation point due to the cutting effect of plastic canopy, but it could reach the light compensation point (this is also the reason why the taste of aubergines produced in solar greenhouses was weak). Under cloudy and overcast conditions, the light is even more insufficient, the light intensity is not enough, the light time is short, does not reach the compensation point. Therefore, photosynthetic efficiency drops sharply, dry matter accumulation decreases rapidly and diseases increase rapidly.
(3) according to the summary of research and production practice, we generally divide the disasters into three levels. 1. Light grade: no sunshine for 3 consecutive days; Or three of the 4 days of lianyin without sunshine, at this time, cucumber, tomato, pepper and other blight, downy mildew began to appear. 2. Intermediate: no sunshine for 4-7 consecutive days; Or sunshine hours <3 h for more than 7 consecutive days; At this time, cucumber, tomato, pepper and other diseases are common, but can be controlled by chemical control and other measures. 3. Continuous cloudy days ≥8 days for multiple grades; Or sunshine hours <3 h for more than 10 consecutive days; At this time, 10% to 20% of the disease is difficult to control, and most of the disease is reduced and continues to develop.
Prospects for development：
In recent years, with the improvement of agricultural productivity, greenhouse has developed rapidly in China. The reasons are as follows :(1) in order to invigorate the market of flowers, fruits and crops, greenhouse is adopted to produce crops in different seasons; (2) spring seedling of rice and other fruits and vegetables; (3) high-tech plant factories that can artificially control the growing conditions of crops to realize soilless cultivation and the development of ecological agriculture such as green food.
At the same time, modern greenhouses have been widely adopted around the world to increase yields by creating conditions suitable for crop growth. The Netherlands has built a glass greenhouse of 110 million m, accounting for a quarter of the world's total production area. It ranks the third in the world in agricultural exports, and has achieved significant yield growth benefits. For example, the single yield of pepper in the greenhouse reaches 30kg/m, and the single yield of tomato reaches 60-70 kg/m. The United States has built a "sapling factory" in SAN Paula, Los Angeles, which USES bioengineering methods to cultivate fruit seedlings with single cells, realizing large-scale industrialization. At present, high value-added agricultural products such as vegetables, fruits and flowers in developed countries are mainly supplied by greenhouse greenhouses.