Agricultural lighting, several core issues to be resolved

           Agricultural lighting market potential is huge, it is beyond doubt the conclusion, researchers Institute of Environment and Sustainable Development of Chinese Academy of Agricultural Sciences, Yang pointed out its long, almost all areas of modern agriculture are closely related with artificial light! Especially in farming (gardening facilities, urban agriculture, etc.), livestock farming (aquaculture facility), aquaculture (breeding facilities, lure fish, etc.), farming (open field production, plant protection attracting insects, etc.), other (edible mushrooms, microalgae, etc.) on the urgent needs of artificial light. Far vegetables this one, we can make a simple idea, in 2014 the total annual consumption of Chinese vegetables only about 130 billion yuan, if the next five years, 10 years, 20 years, 30% of vegetables by agriculture lighting to achieve, then the lighting of the agricultural market can imagine how much.

 

Agricultural lighting market is huge, but based on agriculture involves lighting the complexity of other reasons, bigger, so deep is not an easy thing. Currently, agriculture is still lighting pain points, to explore various ongoing. Basic level: agriculture relates to the complexity of the lighting surface

 

Lighting Research Institute of Fudan University, wood Liu Qing, Zhu Xue Sung from the following five aspects illustrates this point.

 

A multi-disciplinary nature, agriculture lighting

 

If the lighting plants and animals into agricultural lighting illumination range, the subjects they covered include botany, zoology, biometrics, lighting technology, control technology. The first three are in the field of biology, the latter two are the areas of lighting technology, the subject is very wide span, in which several disciplines, the lighting technology is the technology and the content biology experiment process and result evaluation. Overall, knowledge of biology is a most important part of the agricultural lighting, but lighting agriculture mainly refers to the use of LED lighting technology, LED high degree of flexibility, so that the process of agricultural lighting, as the main agricultural or scientists in the biological field, requires a highly complex lighting experts, in order to achieve optimum lighting conditions for a variety of plant and animal species, as well as improve the lighting disciplines success in the visual field, as well as agricultural lighting worth learning. Therefore, discipline and technological progress in agriculture lighting needs of agricultural and biological scientists and scientists in the field of lighting in the area closely.

 

Second, the complexity of the agricultural lighting

 

As an agriculture-related science and technology, agriculture lighting inherited characteristics of agricultural science of complexity, as described above, which includes two aspects: agriculture and lighting.

 

The former species is very large study, and a condition factor per species, the impact is also very much. Several basic elements such as plant growth, sunlight, air, water, in addition, seed, soil, the surrounding environment such as temperature, humidity, climate change, also affect the growth of plants. The animal, since the activities of factors including more, even if all these conditions are consistent, the growth of various plants and animals may also have individual differences, which must be carried out to determine the method of biometrics in agricultural research when lighting the study.

 

Also in terms of lighting, there are multiple variables, including spectrum lighting, intensity, and time period, the form of light (steady or pulse) and the like.

 

These two aspects, determines the complexity of the agricultural lighting, despite the growth of plants and animals through optimized intensity-modulated light can be maintained under the same conditions as the other situation, but the interaction of the various conditions that may exist will study the problem more complication.

 

Third, the test difficulty agricultural lighting

 

The complexity of the agricultural lighting test determines the difficulty of agricultural lighting research is reflected in the specific experimental tests are too many variables. Although the major test case of lighting, by studying different lighting conditions, such as the growth of the irradiation intensity, spectrum, irradiation time, irradiation period, irradiation methods in case of plants and animals, and expect other fixed agricultural conditions such as temperature, humidity, air, moisture, nutrients, seeds. However, these two types of factors may influence each other, thus changing conditions in the actual test experimental study, to be considered very much, while each condition, considerations biometrics, but also have some samples. This makes the test conditions more samples and more, plus each of the test conditions require a certain growth time, the final result in the case of agricultural research is illuminating: test sample is very large, very long time span test, agriculture lighting has become time-consuming, laborious Study fee space. For an example, if the set three kinds of variable light conditions, such as spectral, intensity, irradiation time, the use of 10 variables for each discrete value, it is found that there are two conditions 1000, plus 10 kinds of biological conditions, if, that is, 10,000 kinds case, if the ten samples in each case, it is 100,000 samples, if each sample to be two months, it is conceivable that the difficulty of the test. So the actual study, forced to adopt to reduce the test variables and reduce the number of variables in each test, when I read the literature, the use of lighting conditions often found only in 10 species, there may be employed in the test conditions, no optimal, and thus can not search out the best results.

 

Previously reported Dendrobium fill light test, a total of six greenhouses seedbed (covering an acre), installation and commissioning of the 153 LED lamps and fluorescent lamps 8, 644 samples mark. Data acquisition for seven months, has completed three batches of nearly 200,000 data by analyzing the optimal light conditions. 1,2,3 scene as shown in FIG.

 

 

 

Seen in Figure 3, 113 kinds of different combinations of light environment environment, only two kinds of test conditions appear optimal Dendrobium growth, and the growth of these two obviously far superior than the rest of the growth. Down the remaining 111 kinds of light conditions, growth is not much different than the control group and no fluorescent lighting group. Imagine, if the test 10 kinds or 20 kinds of conditions, it may be unable to search for the best lighting conditions.

 

Before LED, the traditional source of fill light also done a lot of research, but because of the lack of flexibility of traditional light source, it is difficult to achieve a variety of lighting conditions, often only a simple study of several light conditions, as previously mentioned often with more than 10 species. Thus the case, the LED is easy to achieve a variety of lighting conditions, detailed study and re-select the optimal light conditions, there is great practical significance.

 

Fourth, agricultural illumination light weighting of the spectral selectivity

 

Agricultural lighting generally considered to be spectrally selective, which is the same vision lighting, so there is a similar vision lighting spectral weighting curve ViewPort function, often cited curve shown in Figure 4 and 5.

 

 

 

Depending on the human eye to see research function also after a lot of tests was due to the smaller ethnic differences exist, which is currently the ViewPort function is widely used. However, the weighting function of lighting plants currently some theory of finite, more use of plant chlorophyll absorption spectrum in FIG. 5, and are subject to a lot of questions. In fact, look at the different leaf spectral reflectance of various plants, it is very easy to imagine that the weighting function of photosynthesis in different plants likely to be different, so there is a lot of research work to be done. After completion of photosynthesis spectral weighting function of various plants, you can refer vision lighting establish the concept of "flux", ie radiation flux to physical conversion of photosynthesis, and complete the test means.

 

Similar animal and plant lighting, there is a corresponding research work to be done.

 

Diversity V. Evaluation Index

 

Lighting disciplines, science is the study of the visual effect of light on the human eye of science, the main targets are clear and visual comfort, holding containing illuminance, brightness and other indicators, which is glare, flicker and other indicators. Into the agriculture lighting, indicators concern is more complex, including plant growth, the content of certain ingredients, and further refinement may be a plant leaf area, rhizomes, total height, color, composition aspects include sugar, chlorophyll and other indicators. In fact, in addition to many other indicators, such as increased plant growth can be achieved through the fill light, you can turn inhibits the growth of certain things, which will be another type of evaluation.

 

Evaluation animal equally complex and diverse lighting, such as for the growth of broiler fill light illumination, the evaluation index may be a growth rate of chicken, it can be fleshy, protein content, consider selling chicken perception and mortality, and even chicken the feather pecking and so on.

 

The complexity of the evaluation on the study adds to the difficulty of agricultural lighting. It is worth mentioning that, due to the use of multiple lighting conditions, and different growth stages may require different fill light conditions, thus agriculture often combined lighting and control technology, through control technology to achieve full control over the lighting.

 

Other applications are still the bottleneck of the semiconductor light source facing agriculture

 

In addition to the complexity of the above-mentioned disciplines of basic research into the biggest constraints, the technical problem is also manifest in the lack of light formulation research, the molecular mechanism is not clear, the mechanism study stay at the macro level; LED special lamps and energy-saving technology research and lack of control; agriculture LED research personnel (scientific and educational institutions, enterprise level) is extremely scarce. In addition, the cost price and industrial LED light source is a bottleneck in the application and promotion of the agricultural sector faces.

 

Yang expressed its length, in terms of cost, artificial light LED costs have dropped significantly compared with the fluorescent lamp has a certain advantage, but once the investment is high; fill light LED costs are still high, and high pressure sodium relative lack of competitive advantage (fill light 7 ha greenhouse LED590 million euros, high pressure sodium lamp 30-40 million euros).

 

In industry, the low level of industrialization and standardization, market size is difficult to expand; dedicated to small agricultural LED lighting development company dedicated domestic chip manufacturers to invest human and material resources of agricultural R & D lighting red chips less. And more industry, small scale, it is difficult to compete with international giants; LED state agricultural subsidies (such as agricultural subsidies) deficiency. Therefore, at this stage, basic research, technology breakthroughs, reduce costs and strengthen the promotion and the establishment of sustainable and profitable business model is very important.

 

Although the development of agriculture lighting still face difficulties, but China LED road lighting plants are not "devastated." Eighth session of the Fifth Plenary Session that "we should vigorously promote the modernization of agriculture, accelerate the transformation of agricultural development, taking output efficiency, product safety, resource-saving, environment-friendly way of agricultural modernization." Interpretation of the industry, from high yield to efficient TECHNOLOGY agriculture is the only way for modern agriculture. In addition to the information "13 Five Year Plan" also pointed out that all future direction may involve the key support of modern equipment, modern breeding technology. Xi greatly from some time ago to visit the plant factory to be a spy for the National Agricultural illumination attention.

 

In short, still heavy and long road, lighting the development of agriculture depends on close collaboration with agricultural scientists and lighting people, depends on the support of the policy also depends on you my insistence. I believe that one day, China's LED lighting agriculture will be subject to the world's attention.

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