The difference between high pressure sodium lamp and LED plant growth
A large number of production practices and scientific research in agricultural production have proven that artificial plant fill light can not only increase crop yield, shorten planting cycle, but also effectively improve crop quality, and is an important guarantee for efficient production of modern agriculture. In the process of nursery and greenhouse crop management, the use of high-pressure sodium lamps and LED to fill the light, can promote the growth of the crop, change the crop yield, morphology, and physiological indicators.
1, production, quality differences
The high yield and high quality of crops are the ultimate goal of planting and cultivation. The supplement of light by LED can improve the quality of pepper, tomato and eggplant seedlings, and the increase in single fruit quality and yield per plant under light supplementation for 10 hours with significant growth rate. The effect of LED light-increasing production is also reflected in the cucumber planting. The LED can improve the quality of the grape fruit, among which the blue light fills the fruit with the fastest development, the single fruit quality is higher, the sugar content is the highest, and the single grain mass is the highest when the UV light-filling treatment fruit matures. Similarly, the 70W high-pressure sodium lamp significantly increased the yield per plant of the strawberry, and the yield increase was 17.9%. High-pressure sodium lamps and LED fill light have a significant effect on plant morphology. The supplemental light treatment on the side of the LED also improved the visual fruit quality of the cucumber. The LED is added on the basis of the sodium lamp. Compared with the sodium lamp, the color of the cucumber is more vivid.
2. Differences in form indicators
Plant morphology index is an important indicator in the process of plant growth, especially in nursery production. It determines whether the plant can grow healthily after transplantation and cultivation. Under normal circumstances, the growth of coniferous plant seedlings under LED growth is better than that of high-pressure sodium lamps. Photoperiod 12h, Optical density. LED red (630~660nm), Orange light (590~610nm), Blue light (450~460nm), Green light (520~540nm), respectively Compared with natural light, the seedling index of tomato seedlings was significantly increased. After supplementing the light with homemade LEDs, the plant height, stem diameter, and leaf area of the pepper, tomato and eggplant seedlings were also significantly increased, and the inter-LED light supplements significantly increased the mass per unit area of ??the upper, middle, and lower leaves of the tomato. The greenhouse tomato variety 'Maxifort' used high-pressure sodium lamp, natural light, and 3 different ratios of red and blue light to supplement the light. It was found that the tomato leaf area under 95% red+5% blue LED was the number of blades, which is higher than that of high-pressure sodium lamps. The effect of LED lights supplementation on the increase of plant height, stem diameter and leaf area of ??grafted watermelon seedlings was better than that of high pressure sodium lamp treatment. These results all indicate that the LED spectrum ratio is suitable and the plant leaf growth is higher than that of the high pressure sodium lamp. However, there was no significant difference in dry weight and fresh weight between several plant treatments due to the elongation of rose stems and the lower leaf area under LED. This was in line with the study of peppers, tomatoes, geraniums and petunias grown under LED treatment and high-pressure sodium lamp treatment. Seedlings with snapdragon have similar dry matter quality. The seedling height, number of leaves, fresh weight, and dry weight of tomato under high-pressure sodium lamps are greater than that of red-blue LED lamps under the same light density. Moreover, the fresh weight of tomato plants alternately irradiated with LEDs and high-pressure sodium lamps is lower than that of high-pressure sodium lamps alone. The leaves under high-pressure sodium lamps have higher transmittance and reflectance, which also allows the light to better enter the crown. After a series of comparisons, the occurrence of different test results was found to be different from the design of the test method. There was a significant relationship between LED light ratio, temperature, and optical density.
3, physiological differences
Chlorophyll content directly affects the accumulation of photosynthate in leaves. Studies have shown that the gas exchange law and chlorophyll content of coniferous seedlings under LED growth are higher than that of high pressure sodium lamps. In the high-pressure sodium lamp treatment, the chlorophyll content of the rootstock of the rootstock treated with LED light for 9 to 13 days was significantly higher than that of natural light. LED lights make up for the accumulation of photosynthetic pigments in cabbage. In the eight growth tests conducted by Ptushenko, the average photosynthetic pigment content (per unit leaf area) of five plants grown under LED fill light was higher than that of high pressure sodium lamps. The chlorophyll a and chlorophyll b contents of tomato seedlings with a combination of red and blue LED lamps were higher than that of high-pressure sodium lamps at the same optical density. Carotenoids are auxiliary pigments for photosynthesis of chloroplasts. Their functions are to consume excess energy in PS II and to protect chlorophyll from glare. Dlugosz research shows that supplementing with high-pressure sodium lamps will increase the concentration of carotenoids and nitrates in lettuce. Under the LED light supplement, the contents of soluble sugar, carotenoids and nitrogen in leaves of pepper, tomato and eggplant seedlings all increased in different degrees, and the transpiration rate was accelerated. When the plants were grown simultaneously and tested with high-pressure sodium lamps and LED (RB, RW) lighting, it was observed that the water use efficiency of tomato and eustoma when supplemented with high-pressure sodium lamps was higher than that of LED treatment, and the transpiration rate was lower than that of the LED treatment, in net CO2. There was no difference between the exchange rate and the final biomass, however, the maximum photosynthetic rate was the same under different treatments. In addition, LED (R:FR=3.09) 500ol/(m) can significantly affect the flowering time and flowering rate of lentils. Both LED and high-pressure sodium lamps can increase the photosynthetic pigment content, and the LED is higher in the accumulation of photosynthetic pigment than the high pressure sodium lamp, and the transpiration rate is higher than that of the sodium lamp. The specific spectral ratio of the LED can also be used for the flowering of some plants. In addition, it must be pointed out that the chlorophyll content alone cannot positively indicate the effect of light on plant photosynthetic ability, because when the plant encounters a low optical density environment, it automatically adapts low light stress, enriching more in the leaves. Chlorophyll for more light energy.
Compared to traditional light sources, high-pressure sodium lamps and LED have obvious advantages. With high-pressure sodium lamps and red and blue LED lights, the top of the plant canopy is filled with light, both of which can achieve the same output. LEDs only need to consume 75% of the energy. It has been reported that under the same conditions of energy efficiency, the initial investment cost of LED is 5 to 10 times that of high-pressure sodium lamps. The initial high cost makes the cost per LED of the use of high-pressure sodium lamps 2 to 3 times higher in the use of 5 years. For flowerbed plants, the 150W high pressure sodium lamp and 14W LED can achieve the same effect, compared to 14W LED more economical. In the 550m2 area, the cost of using a high-pressure sodium lamp per kilogram of cucumber alone is $1.3, the cost of a sodium lamp plus a single row of LED lamps is $1.45, the cost of a sodium lamp plus two rows of LEDs is $1.72, and the profit-to-cost ratios are 2.31 and 2.07, respectively. 1.74. The use of LEDs in sheds requires a large number of erections, and the cost of one-time investment is relatively large. For individual vegetable farmers, investment is more difficult. Whether the cost-reduction effect caused by LED energy-saving can fully compensate for its initial investment and subsequent financial costs in its useful life, it needs careful accounting and measurement.