Plant supplementary lamp is a kind of lamp which provides light source for plant growth and development according to the natural law of plant growth and the principle of plant photosynthesis by using sunlight instead of sunlight.
Necessity of light supplement
Illumination is closely related to crop growth. Capturing the maximum light energy and giving full play to the potential of plant photosynthesis will directly affect the benefits of agricultural production. In recent years, due to the market demand, greenhouse greenhouse is widely used to produce counter-season flowers, fruits, vegetables and so on. Because of the short sunshine time in winter and spring, slow growth of crops and low yield, it is urgent to supplement the light. Most of northern China is located in eastern Asia and belongs to temperate monsoon climate.
In winter and spring, the Siberian cold air flows southward, sometimes due to the convergence and fusion of warm and cold air flows to form rain and snow. There are few low temperature and few sunshine for 1-3 days, and more cloudy and few sunshine for 7-8 days. According to the statistics of Beijing in the past 50 years, the probability of this long-term cloudy weather is about 20%, 40% in the past 10 years, and twice in the past three years, more than 60%. That is to say, Beijing's hazards in winter and spring are becoming more and more serious, and have become a major disastrous weather in winter and spring protected areas. The direct threat to protected land production represented by solar greenhouse is as follows:
(1) When the illumination intensity is lower than the compensation point, the consumption of organic matter is more than the accumulation, and the dry quality of the plant decreases or even dies. Even under the condition of weak light, the growth of the plant is weak and tenuous.
(2) Influencing flowering and fruiting. Solanaceae and melon vegetables have certain requirements for light time and intensity. If the light time of watermelon is less than 11 hours, all young fruits will fall off. Vegetables with moderate light intensity requirements such as peas, beans, celery, radish, onions, etc. Vegetables with low light intensity such as lettuce, spinach, Artemisia and ginger require low light intensity. Solanaceous vegetables are produced in Solar Greenhouse in Beijing. Even in sunny days, the light intensity can not reach the light saturation point due to the reduction of plastic curtain, but it can reach the light compensation point (which is also the reason why the taste of Solanaceous Vegetables produced in solar greenhouse is weak). In cloudy and overcast conditions, the illumination is more insufficient, the intensity of illumination is insufficient, the illumination time is short, and the compensation point can not be reached. As a result, the photosynthetic efficiency decreased sharply, the accumulation of dry matter decreased rapidly, and the disease increased rapidly. The loss has become a foregone conclusion.
(3) According to the summary of research and production practice, we generally classify the disaster into three levels. 1. Light grade: No sunshine for 3 consecutive days; or 3 consecutive days without sunshine for 4 consecutive cloudy days. At this time, diseases such as cucumber, tomato, pepper and downy mildew began to appear. 2. Intermediate: No sunshine for 4-7 days in a row; or sunshine duration < 3 hours for more than 7 days in a row; or 2 times of light oligophoto in January, when diseases such as cucumber, tomato and pepper are common, but can be controlled by chemical control measures. 3. Severe successive cloudy days (> 8 days); or sunshine hours (< 3 hours) for more than 10 days; or two intermediate oligopolies occurred in January. At this time, 10% to 20% of the diseases were difficult to control, and most of the diseases appeared yield reduction, and continued to develop.