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Before determining the space between greenhouses, it is still necessary to carry out relevant popular science knowledge in the greenhouse industry. This is very necessary for ordinary users. The term "greenhouse" is just a colloquial expression in daily life. There is no such type in the greenhouse industry, but in the greenhouse industry, it is generally divided into three categories by name, namely spring and autumn greenhouses, solar greenhouses and multi span greenhouses. ▲ Spacing between solar greenhouses of different greenhouse types In the practical application of greenhouse, the space between greenhouses is mainly considered whether there is shelter, which affects the lighting of crops in the greenhouse. In fact, there are three different types of greenhouses, which have a large gap in terms of light shielding. Spring and autumn greenhouses and multi span greenhouses have a common feature, that is, they are all made of transparent covering materials, which is relatively low for the sunlight shielding of the front and rear greenhouses. The solar greenhouse is different. Its biggest feature is that it has a wall, which can be said to be 100% sunshade. During the construction of the solar greenhouse, the distance blocked by the back wall directly affects the position of the greenhouse behind. ▲ The space between greenhouses in spring and autumn is very small ① Spring and autumn greenhouses and multi span greenhouses also need a certain distance directly For the covering materials of these two greenhouses, although they are transparent. From the perspective of light transmission, the influence of sunlight on plant growth can be ignored. However, there must be a distance between greenhouses, which is mainly related to the practical application of greenhouses, especially when the length of greenhouses is relatively long. For the materials that need to be transported for planting crops in greenhouses, there should be a corridor that is wide enough directly in the two greenhouses to facilitate vehicle access. Another point is the maintenance of greenhouses, especially multi span greenhouses. If the covering materials are damaged, large equipment will be required for hoisting operations, and a maintenance channel will be required, which is basically more than 4 meters away. ▲ Actual construction spacing of solar greenhouse ② The spacing between solar greenhouses must be considered The solar greenhouse itself is a special greenhouse, and its distribution area is also in the north, which can also be understood as a unique greenhouse type in the north. As for this reason, it has a wall structure, and this wall structure has different forms, but this is not the theme today. As for the influence of the spacing between greenhouses, the main problem of sunlight shielding on the walls of solar greenhouses will affect the construction of the greenhouses behind, that is, to ensure that there is an appropriate distance between greenhouses. In this way, the lighting time of the crops in the greenhouse will not be affected, otherwise, the normal growth of the crops will be affected. Summary: Next, we will give full consideration to the space between solar greenhouse construction, which has a great impact on crop growth due to greenhouse shielding. How to solve this problem? What's more, the factors involved are convenient, not just the wall height. Influence of Regional Factors on Solar Greenhouse Construction For solar greenhouse construction areas, it is also easy to understand this point. In order to make a simple analysis here, it mainly refers to the local conditions of construction, such as hilly areas and plain areas. When building greenhouses, their spacing is very different. In addition, in greenhouse construction, it is necessary to make full use of land and build the principle of waste of land resources. If the hilly area is built in the Chaoyang area, it is all ladder type, and the greenhouse is definitely the smallest indirectly. The plain area is different. It must take into account a dimension. Moreover, solar greenhouses are mainly used in winter. It is necessary to take into account the winter solstice, when the shadow length of the sun is the longest. Consideration of light time required for planting crops On the use time of solar greenhouse, you netizens also basically understand. It is mainly to solve the problem of off-season vegetable planting in winter. Because of its good heat preservation, vegetable farmers like to call it the greenhouse. Another problem that has to be considered here is the lighting time. This light time is not only the need for photosynthesis for crop growth, but also the time for solar greenhouse to store heat during the day. Different crops have different needs for lighting time. For example, cucumber, tomato, pepper and other crops require more than 6 hours of light. In addition, there are some low light crops, such as celery, rape, Chinese cabbage, which need 4 hours of light to ensure their normal production. ▲ Actual environment of soil wall greenhouse How to calculate the distance between solar greenhouse construction It is true that there is a scientific calculation formula for this, but it is mainly used in plain areas. For hills or slopes, special consideration is required, because there will be a problem of height of drop, and the construction spacing between them is generally small. This time, we mainly focus on the design between solar greenhouses. At least we should ensure that the greenhouse has a lot of 6 hours of light time, which can ensure the planting of various types of plants. It is also consistent with the recycling of multiple crops in the greenhouse, and more consistent with the ecological development of the greenhouse. You can refer to the indirect calculation form suitable for the greenhouse construction planning in the surrounding areas of Hebei. ① Basic conditions for the construction of solar greenhouse Here we need to provide the basic conditions for the design of the solar greenhouse. The back wall height of the solar greenhouse is 2.8m, the ridge height is 3.5m, and the projection distance of the back slope is 1.2m. The wall thickness depends on whether it is a brick wall or a soil wall. The brick wall is generally 0.24m, and the soil wall is generally 0.5-1m. A fixed value is required here. Take the brick wall as an example, select 0.24m. ② Calculation of Space between Solar Greenhouses Before the calculation, we need to check the local dimension. The requirement is to guarantee a minimum of 6 hours of light time. The dimension is 40 degrees, which is generally a north-south construction. That is, from 9:30 a.m. to 10:00 a.m., there must be sunshine in the front room of the greenhouse. For this sunshine spacing coefficient, L0, is 2.993 meters, this data can be queried. In this calculation process, it is necessary to know the slope of the roof of a solar greenhouse. There is also a fixed calculation formula that can be used to calculate this, and it is very simple when there are data. The formula is as follows: β = Tg-1 [(ridge height back wall eave height)/(back slope projection width+back wall thickness)] =tg-1[ ( 3.50- 2.80) / ( 1.20+0.24)] = 20.2° The formula for calculating the distance between solar greenhouses is: Greenhouse indirect=L0 × Ridge height - (projection width of back slope+thickness of back wall), 2.993 × 3.5 - (1.2+0.24)=9.04m.

Intelligent planting of agriculture by using Internet of Things technology has become a hot spot. Intelligent information management technologies such as intelligent greenhouse monitoring system are the mainstream of modern agriculture development. Domestic smart greenhouse management is still extensive At present, some smart greenhouse demonstration bases emerging around the country rely more on greenhouse environment control methods based on set values. The main control methods are as follows: first, set the target parameters (such as indoor temperature, humidity, light, etc.) based on experience, the controller makes decisions based on the gap between the detected real-time results and the target parameters, and achieves the target value by adjusting the opening and closing of the equipment through the environment. This is a relatively extensive intelligent management mode widely used in domestic greenhouses at present. To a certain extent, it is just the use of computers instead of human hands to press the switch, which cannot be regarded as real intelligence. Let plants "speak" Modern facility agriculture is good at effectively regulating crop growth environment, and the primary task of regulation should be to understand crop demand. It is to truly perceive when plants are hungry, thirsty, fat or thin; What temperature does it need for vegetables? When should I water it? When should I fertilize? How much water? How much fertilizer? All problems are clear at a glance. Then precise control will be carried out according to the actual needs of its growth. To understand plant "language", the secret lies in plant life information perception technology. To achieve "dialogue" with plants, it is necessary to accurately and effectively collect soil nutrients, meteorological environment, plant nutrition, growth data, etc. that affect plant growth. Smart greenhouse needs real "super brain" Intelligent detection and control technology is the front-end and back-end of intelligent facility agricultural production. After information perception, it is another key technical problem to solve the problem of "what is lacking and what is supplemented". The control process of greenhouse environment is extremely complex, with many variables, strong coupling, large interference and other characteristics. A set of scientific and practical intelligent control system is like a "super brain". How to establish a comprehensive greenhouse control model integrating crop growth model, environmental control model and cost model? How to realize the accurate allocation of nutrient components? How to achieve multi-objective optimization control? This is what the intelligent control system should do. The intelligent system works like this: The intelligent greenhouse system collects plant growth information, real-time environmental data such as air temperature and humidity, soil moisture, soil temperature, carbon dioxide, and light intensity in the greenhouse, and transmits them to the control center. The central platform system compares the latest monitoring data with the preset environmental parameters suitable for agricultural growth. Once it is found that the data monitored by the sensor has a deviation from the preset value, the computer will automatically send a command to intelligently start the ventilator, sunshade, humidification, watering and other equipment connected to the system to work. The relevant equipment will not stop working until the environmental data in the greenhouse reaches the preset data range of the system. In daily life, automated and unmanned management of the greenhouse is implemented through the remote mobile terminal of the system. Six Trends of Intelligent Greenhouse Development In terms of long-term development, China's greenhouse market has huge development potential, and smart greenhouse users tend to be rational and mature. It is generally required that greenhouses tend to be rationalized in layout, scientific in adaptability to local climate conditions, and popularization of greenhouse application technology. The development trend of intelligent greenhouse in recent years can be summarized as follows: 1. The intelligent greenhouse is further combined with modern industrial technology to improve the quality of hardware and enhance the supporting capacity. China's facility agriculture should further develop in building structure engineering, material engineering and water-saving and energy saving engineering. While improving the quality of the main structure, the supporting capacity should be constantly enhanced. 2. The production of facilities and facility agricultural products is developing towards standardization, including the performance, structure, design, installation, construction and use standards of greenhouse and supporting facilities, the standards of facility cultivation technology and production technical procedures, and the standards of product quality and testing technology. 3. Strengthen the research and development of post harvest processing technology, including the process technology and supporting facilities and equipment for post harvest cleaning, grading, pre cooling, processing, packaging, storage, transportation and other processes, so as to improve the added value of products and international market competitiveness. 4. Intelligent greenhouse combined with computer automatic control technology. Realize automatic monitoring of light, temperature, water, fertilizer, gas and other factors and automatic control of operating machinery. 5. Combined with information technology, establish network management, mode operation, remote service, etc. with products, technologies and markets as the main contents. 6. Combined with biotechnology, new crop varieties with strong stress resistance, disease and insect resistance, storage tolerance and high yield will be developed to improve the yield and quality of greenhouse crops; We will make use of special means of production such as biological agents, biological pesticides, and biological fertilizers to develop precision agriculture and provide more pollution-free and safe green and healthy food for the society.

There are many kinds of films suitable for solar greenhouse. According to the different resin raw materials, it can be divided into polyethylene (PE) film, polyvinyl chloride (PVC) film and vinyl acetate (EVA) film; According to its performance characteristics, it can be divided into ordinary film, long-life film, drip free film, long-life drip free film, diffuse reflective film, composite multi-functional film, etc. The properties of these films have their own characteristics and strengths. Combined with the current production needs, this paper introduces several commonly used films for reference when building greenhouses. Types and characteristics of films (1) Polyethylene ordinary film (PE) The light transmittance of the new film is about 80%; Weak dust absorption, without the phenomenon of excessive dust absorption (tackiness) caused by plasticizer precipitation of polyvinyl chloride (PVC) film. It has strong low temperature resistance, low temperature brittleness is - 70 ℃, and it can still maintain softness at - 30 ℃. The relative density is 0.92g/cm3, and the infrared transmittance is more than 70%. The heat preservation performance at night is poor, not as good as PVC film. The fog drop property is heavy, and the weather resistance is poor. The service cycle is 4-5 months. It is not sun resistant, and the high temperature softening degree is 50 ℃. Therefore, it is not suitable for covering cultivation in high temperature season. It can be used for covering cultivation in early spring and late autumn. It is not easy to bond after tearing. At present, there is no suitable repair adhesive, and it can only be heat sealed when splicing. (2) Polyethylene long-life film It is made of polyethylene as the base resin by blowing after adding a certain proportion of ultraviolet absorber, anti-aging agent and antioxidant. The weather resistance is good, and the service life is 1.5~2 years. The thickness is 0.1~0.12 mm, the amount of film used per 667 m2 is 100~120 kg, and the breadth varies from 1 m, 1.5 m, 2 m, 3 m, 3.5 m, and 4 m, that is, the width of a single breadth after opening is 2 m, 3 m, 4 m, 6 m, 7 m, and 8 m. The application area has expanded rapidly in recent years. Although the one-time investment is larger, it has a long service life and can be used for almost four crops, which is more economical than ordinary PE film. (3) Polyethylene drip free long-life film It is made of polyethylene as the basic resin, added with anti-aging agent and drip free additive, and then blown. The weather resistance is good, and the service life is more than 1.5~2 years. No condensation. The thickness is 0.1~0.12 mm, the dosage is 100~130 kg per 667 m2, and the width varies from 1 m, 1.5 m, 2 m, 3 m and 3.5 m, which is suitable for various greenhouses and greenhouses. It can also be used as a two curtain covering in greenhouses and greenhouses. (4) PVC common membrane The agricultural film is made of PVC as the basic resin. It is resistant to high temperature and sunlight. Its insulation at night is better than that of polyethylene film, and it is resistant to aging. The fog drops are light. After the film is torn and broken, it can be bonded with adhesive, which is convenient to repair. The thickness is 0.1~0.12 mm, and the width and diameter are 1 m, 2 m and 3 m. The dosage is 130 ~ 150kg per 667m2, and the relative density is 1.25 g/cm3. The coverage area of the same amount is 24% more than that of the polyethylene film with the same thickness. The new film has good light transmittance. However, with the extension of the coverage time, the plasticizer gradually precipitates, and the film surface has a sticky feeling, so the dust absorption is strong, and it is difficult to clean. The light transmittance is quickly reduced, and the low temperature resistance is poor. The low temperature brittleness is - 50 ℃, and the hardness is - 30 ℃; PVC film is more suitable for areas with small wind sand and less dust, especially for northern areas where night insulation cultivation is required. (5) Multifunctional membrane With polyethylene as the basic resin, a variety of additives are added, such as drip free agent, heat preservation agent, anti-aging agent, etc., to make a film have a variety of functions, such as longevity, drip free, heat preservation, etc., to achieve multiple effects at the same time. In terms of processing technology, one is to evenly mix the basic resin with various additives and blow to form a film; the other is to form a composite film, such as a three function composite film, in which a drip free agent is added to the inner layer and an ultraviolet absorber is added to the middle and outer layers to form a multi-functional composite film. The thickness is 0.06~0.08 mm, the service life is more than 1 year, the transparency and thermal insulation are good, the temperature rises quickly in sunny days, and the thermal insulation effect is available at night. It is suitable for large, medium and small greenhouses, greenhouses, and as a second curtain. Due to its thin thickness, the film coverage area per unit weight is large, and the consumption per 667 m2 is only 60~100 kg. (6) Diffuse reflective film With polyethylene as the base resin, a certain proportion of diffuse reflective crystal nucleus is added. When the direct sunlight penetrates this film, it will be converted into flat light under the effect of diffuse reflective crystal nucleus, and will be more evenly transmitted to all parts of the greenhouse, reducing the transmittance of direct sunlight. This can not only reduce the peak temperature in the shed around noon, reduce the damage of high temperature to crops, but also help the uniformity of plant growth in the shed. At the same time, the heat preservation at night is good, and the accumulated temperature of greenhouse is higher than that of PE and PVC ordinary agricultural film. (7) Polyethylene dimming film (light conversion film) A new type of plastic film was blown from low density polyethylene (LDPE) with light conversion agent. It can convert the ultraviolet light in natural light into red light and infrared light, and reduce the ultraviolet light that is not beneficial to plants. The increase of red light and infrared light can improve the photosynthetic utilization rate of plants, strengthen photosynthesis, and increase the indoor air temperature and ground temperature in the shed. The agricultural film has the characteristics of long life, aging resistance and good light transmittance. The thickness is 0.08-0.12mm, the amplitude diameter is 1-5m, the tensile strength is greater than or equal to 13mPa, the elongation at break is greater than 305%, and the right angle tear strength is greater than or equal to 50kg/m. The service life is more than 2 years, the light transmittance is more than 85%, and the warming effect is not significant under weak light.

The status and characteristics of solar greenhouse in china in agricultural production, solar greenhouse can make full use of solar heat resources, reduce environmental pollution, to a certain extent, to achieve efficient land use. At present, the solar greenhouse in China is developing rapidly, and the construction area has reached nearly 16 × 104 hm2, with considerable economic benefits. With the continuous improvement and development of the construction technology of the solar greenhouse, the scientific and technological content of the solar greenhouse is also increasing, and the energy-saving intelligent solar greenhouse will gradually take shape. 2. Construction principle of energy-saving solar greenhouse The construction of energy-saving solar greenhouse shall meet the following requirements: First, it shall have good light transmission performance to ensure high utilization rate of sunlight; Second, it is necessary to have good warming and heat preservation performance to ensure faster warming under sunlight; The third is to have good ventilation and moisture removal performance to ensure that the humidity in the solar greenhouse is within reasonable requirements; Fourth, it is necessary to have good windproof performance to ensure that the structure of the solar greenhouse is firm and the service life is long; Fifth, it should be easy to operate, build, manage and invest less. 3 Construction technology of energy-saving solar greenhouse 3.1 Orientation selection of energy-saving solar greenhouse The orientation selection of energy-saving solar greenhouse mainly refers to the selection of the orientation of energy-saving solar greenhouse according to the actual solar radiation. The orientation of energy-saving solar greenhouse should be north to south, and extended from east to west, so as to ensure long sunshine reception time and high light utilization rate. In places where the temperature is not too low in winter, and the sun rises early, the sunlight is sufficient in the morning, and the selected position is south by east; In places where the temperature is relatively low in winter, and the sun rises relatively late, the sunlight exposure time in the morning is not long, so the orientation should be south by west. The preference of energy-saving solar greenhouse, whether south by west or south by east, should be scientifically and reasonably selected according to the climate, terrain, topography and other conditions on the spot, and the east or west should not exceed 10. If the construction cannot be carried out according to the above requirements due to geographical conditions and other reasons in the actual operation of selecting the orientation, adjustment shall be made according to the following methods and measures. On the construction site of the solar greenhouse, set up a benchmark perpendicular to the ground, observe the projection of the benchmark in the 12:00-12:30 interval in sunny weather, select the shortest projection of the benchmark and make its vertical line. With the vertical foot of the vertical line as the base point, the vertical line rotates at a scientific and reasonable angle. At this time, the rotated vertical line is the reference line in the direction of the back wall, and this reference line establishes the orientation of the energy-saving solar greenhouse. The energy-saving solar greenhouse should not only consider the choice of orientation, but also consider whether the transportation of the selected land is developed, how the soil moisture is, whether it is in a higher terrain, how the soil permeability is, how the flood control and waterlogging prevention capacity is, how the soil fertility is, and so on. 3.2 Structural design of energy-saving solar greenhouse The structural design elements of energy-saving solar greenhouse include front roof and front roof inclination, rear roof and rear roof inclination, horizontal projection length, span, height, greenhouse area, greenhouse wall thickness, etc. The optimization of these structural design elements can greatly improve the light utilization rate, heat preservation performance, heating speed, wind resistance and service life of solar greenhouse. 3.2.1 Front roof and its inclination The front roof of the energy-saving solar greenhouse is the daylighting surface. Its shapes include vertical slope type, double fold type, triple fold type and arch circle. The arch circle also has parabola, cycloid, arc and other shapes. At present, there are two types of solar greenhouse commonly used: vertical slope type and parabola type. Due to structural limitations, the vertical slope type solar greenhouse must be pressed with bamboo pole and bound with iron wire. The iron wire passes through the membrane to make holes on the membrane, reducing the heat preservation effect of the solar greenhouse. At the same time, it also forms water droplets on the bamboo pole, which will affect the growth of vegetable crops in the solar greenhouse. Parabolic solar greenhouse has many advantages compared with vertical slope solar greenhouse, such as firm structure, good compression resistance, large lighting area, fast heating speed, high lighting efficiency, good light transmission performance, high light utilization rate, convenient to pull up and put down the thermal insulation cover, convenient to press the film with film pressing rope, parabolic type is not easy to form water droplets, even if there is one, it will flow along the parabola, parabolic type has less snow and is convenient to clean. The inclination angle of the front roof is calculated. According to the calculated inclination angle of the front roof, the appropriate span and height can be selected according to the corresponding relationship between the span, height and inclination angle of the front roof of the solar greenhouse. The inclination angle F of the front roof indicates that the reasonable inclination angle of the front roof should meet the conditions of Formula (1). 3.2.2 Rear roof and its inclination and horizontal projection length The back roof of the solar greenhouse is designed, which can be flat or slightly arched. The back roof can generate the cold northwest wind in winter in the north, making the cold air flow along the back roof, which has a significant effect on improving the thermal insulation of the solar greenhouse. The rear roof can not only improve the height of the solar greenhouse, increase the angle of the lighting surface, facilitate the sunlight penetration, but also facilitate the placement of the insulation covers (straw mats, quilts, etc.) on the lighting surface after being uncovered. However, the back roof blocks the scattered light in the sky from the north of the solar greenhouse, affecting the light conditions behind the solar greenhouse, resulting in the crops behind the solar greenhouse being significantly inferior to the previous crops in terms of growth, development, yield, quality, etc. In order to ensure the indoor temperature of solar greenhouse in cold winter and balance the advantages and disadvantages, it is necessary to design the rear roof. The angle of inclination of the rear roof, that is, the elevation angle of the rear slope, should be 5 °~8 ° higher than the local sun elevation angle at the noon of the winter solstice. The angle of inclination of the rear roof determines the speed of the cold air flow. Too large the angle of inclination is not conducive to the flow of cold air along the back, and too small the angle of inclination affects the sunlight can not directly shine on the interior of the rear roof, which is not conducive to improving the temperature in the solar greenhouse, and affects the lighting effect behind the solar greenhouse. The solar altitude angle refers to the angle between the solar rays of a certain place on the earth and the surface section connected with the earth center through the place. The sun elevation angle is determined by the latitude of the location. In the area of 35 ° north latitude, the sun elevation angle is 31.6 °, the elevation angle of the back slope should be 36.6 °~39.6 °, and the horizontal projection length of the back roof should be about 1 m to reduce shading. 3.2.3 Height and north-south span of solar greenhouse The height and north-south span of the solar greenhouse determine the lighting area, the angle of lighting surface and the structural strength of the greenhouse. The height of the solar greenhouse is the distance from the intersection of the front roof and the rear roof (the highest point of the solar greenhouse) to the reference ground. The north-south span is the distance from the back wall of the solar greenhouse to the southernmost end of the front roof framework. The ratio of the height of the solar greenhouse to the north-south span shall be calculated scientifically, and the shape formed by this ratio shall be checked for structural strength through mechanical analysis, with sufficient safety factor. The lighting area and the angle of the lighting surface determined by this ratio (which determines the size of the sunlight incidence angle) should also be scientifically calculated through indicators such as temperature rise, thermal insulation and sunlight utilization rate, so as to make them meet the construction requirements of energy-saving solar greenhouse. The north-south span can be calculated by the formula: north-south span=height of the highest point of the greenhouse × Ctga (a is the angle of the lighting surface)+the projection length of the rear roof (3) 3.2.4 Area of solar greenhouse Area of solar greenhouse=north-south span of greenhouse × Length of greenhouse. (4) The area of solar greenhouse shall be designed within a scientific and reasonable range, generally 0.067 hm2~0.034 hm2. The solar greenhouse with reasonable area can enhance the thermal insulation performance, facilitate management and operation, and improve the work efficiency. The reasonable area can effectively reduce the occurrence of cold damage or freezing damage in severe cold weather, and reduce the time for pulling up and putting down the covers in winter. The area parameter of the solar greenhouse is an important economic and energy saving indicator. 3.2.5 Height of back wall The height of the back wall refers to the distance between the intersection line of the interior surface of the back slope and the interior surface of the back wall of the solar greenhouse and the interior plane of the greenhouse. The height of the back wall can be determined according to Formula (5), and the height of the back wall of the solar greenhouse should generally be 2.5~4.5 m. h = H-btan α R. (5) 3.2.6 Arch spacing and wall thickness The arch spacing is determined by arch bar strength, covering material performance and local wind and snow load. The wall thickness of the solar greenhouse is determined by the thickness of the local frozen soil layer, which is generally twice the thickness of the frozen soil layer. 3.3 Covering materials of energy-saving solar greenhouse The transparent covering material for the daylight surface of the solar greenhouse has the energy saving effect through optimal selection, and also has the characteristics of good light transmission, strong compression and tension resistance, good thermal insulation, and long service life. Polyethylene dripless film, three layers Extruded composite film, polyethylene drip free light conversion film, ethylene vinyl acetate three-layer co extruded drip free heat preservation and anti-aging film, PVC drip free film and other multi-functional composite films. 3.4 Wall of energy-saving solar greenhouse The wall of the solar greenhouse not only has the functions of heat preservation, support, closure, etc., but also can store the heat of solar energy in the day, and release the heat stored in the day at night, playing a role in warming the night. The wall can be divided into solid wall and hollow wall, and the hollow wall can be divided into two types: thermal insulation filler material and non thermal insulation filler material. 4 Conclusion Through the optimization analysis of the orientation selection, structural design, covering materials and foundation walls of the solar greenhouse, the light utilization, heat preservation, moisture removal and wind resistance of the solar greenhouse are improved, and the energy saving effect of the solar greenhouse is improved.

1: Control the lighting inside the greenhouse. Light is an essential condition for vegetable growth. Without light, vegetables cannot produce chlorophyll and grow normally. Therefore, we should pay attention to the control of light when planting vegetables in greenhouse. The light intensity varies greatly in different seasons. Generally speaking, there is less sunlight in winter and early spring. Because the greenhouse is isolated from sunlight, vegetables can receive very little light. In this period, farmers should lift the plastic film to ensure that the vegetables get enough light. 2: Pay attention to ventilation. The greenhouse is an almost completely closed space. In this environment, the vegetables themselves may react and produce some toxic gases. If these gases are not discharged in time, the normal growth of vegetables will be hindered. Timely ventilation can ensure the normal growth of vegetables. 3; Select appropriate greenhouse film. The selection of greenhouse film should take into account the warmth retention and non-toxic. With the improvement of people's education level and quality of life, more attention should be paid to green food. When planting vegetables in the greenhouse, if the greenhouse film has certain toxicity, it will not only hinder the normal growth of vegetables, but also make vegetables contain toxic substances to varying degrees. In addition, attention should be paid to the assembly of greenhouse film. A high-quality greenhouse film can enable vegetables to grow under appropriate temperature and humidity conditions. 4: Select vegetable varieties scientifically. There are various types of vegetables, and different vegetables have different requirements for the environment. The growers should consider whether the local terrain can meet the growth needs of vegetables and whether the vegetable varieties can meet the market demand, so as to ensure that the vegetable varieties planted can improve the farmers' income. 5: Do a good job in pest prevention. Vegetables will be damaged by diseases and pests at one or several stages, resulting in yield reduction. Farmers should timely observe, prevent the occurrence of pests and diseases, take measures to eliminate pests and diseases, minimize the impact of pests and diseases, and clean the greenhouses. 6; Scientific irrigation. Water is a necessary condition for the growth of all things. Vegetables need sufficient water to grow. Vegetables without water cannot grow normally, or even die directly. Therefore, planting vegetables must be watered in time.

Based on the existing national and industrial standards for greenhouse acceptance standards, the methods and steps of construction project acceptance can be appropriately applied in the process of acceptance, and the acceptance can be carried out step by step and area by area. 1. Category acceptance The whole greenhouse project is divided into three parts: civil engineering, structure and supporting facilities for acceptance. The civil works mainly include the greenhouse foundation, auxiliary rooms, pools and other civil works, which can be accepted in strict accordance with the building standards. The greenhouse structure includes the main body of the greenhouse, covering materials, internal and external sunshade systems, etc., which can be checked and accepted by referring to the existing standards for greenhouse acceptance, the actual situation of the greenhouse construction site, and the local standards. The sprinkler irrigation system (water system) in the supporting facilities can be designed, constructed and accepted according to the Technical Specifications for Sprinkler Irrigation Projects issued by the Ministry of Water Resources. For greenhouses with more electrical control equipment, larger electrical control systems and higher degree of automation, the power distribution system can be checked and accepted in strict accordance with the building standards; For greenhouses with simple electrical control system, the acceptance can refer to the corresponding greenhouse industry standards. For supporting equipment, such as movable seedbed, heater, fan wet curtain cooling system, mobile sprinkler, seeding equipment, etc., the equipment acceptance method can be adopted, and the equipment performance, brand, etc. can be accepted according to the design requirements or the bid of the bid winner. 2. Step by step acceptance For a single greenhouse or small-scale greenhouse project, the acceptance process is basically the same as that of the construction project, which is to complete part of the project and accept part of it. Finally, the overall acceptance of the whole project is carried out according to the acceptance of the sub project. For the acceptance of subprojects, all subprojects can be classified according to the classification method, and then classified for acceptance according to the design requirements and standards. For large-scale greenhouse projects, such as the construction of the entire park or greenhouse group, the entire project can be divided into several areas for construction and acceptance. For the acceptance of each area, the classification method is still used for gradual and item by item acceptance. In this way, the quality of the whole greenhouse project can be strictly guaranteed to meet the requirements of design and use, and the acceptance can be standardized to facilitate the sorting of acceptance data and reduce disputes during construction. 4. Work after acceptance of greenhouse construction project The data after acceptance shall be sorted and managed separately according to the building standard acceptance and greenhouse standard acceptance data for future reference. The acceptance of greenhouse groups can be sorted out according to zones or individual greenhouses due to the large amount of data. For the acceptance of greenhouse projects, different regions and units have accumulated some effective experience with their own characteristics. However, for the entire greenhouse industry, the imperfect acceptance standards are the main reason for the embarrassment of the acceptance of greenhouse projects. Gradually improving the design and acceptance standards of greenhouse will play a positive role in promoting the development of greenhouse industry, agriculture and rural areas in China.

Agriculture is one of the main industries in many industries in China. Greenhouse is an indispensable part of agricultural development, and its role is increasingly important. In recent years, the construction and application of green prevention and control technology, water-saving irrigation, soil testing and fertilization and other related agricultural technologies and projects have formed an eco-friendly facility agricultural production mode. With the rapid development of agriculture in China, the development of facility agriculture has also entered a new stage. Many agricultural growers increasingly prefer to use greenhouses. Under the guidance and leadership of the government, greenhouses have also been increasingly intelligent, mechanized and large-scale. 1. Realize off-season production of agricultural and sideline products In traditional agricultural planting, most agricultural products suitable for seasonal growth are selected according to the 24 solar terms. The category of fruits and vegetables is relatively simple. The use of greenhouse can realize the early output of fruits and vegetables, and extend the harvest period. There are many kinds of fruits and vegetables planted to meet people's demand for fresh fruits and vegetables. 2. Realize green pollution-free planting and production of fruits and vegetables Under the premise of continuous economic growth, people's living standards are constantly improving, and the requirements for fruits and vegetables are also increasing. For the planting and production of greenhouse greenhouse facility agriculture, measures such as arranging dust screens at the ventilation openings, entrances and exits of the greenhouse can reduce the losses caused by pests and diseases to a certain extent, reduce the impact of outdoor dust, haze, etc. on fruits and vegetables, adjust the specific climate environment through the arrangement of external facilities, reduce the damage caused by natural disasters to crops, and produce high-quality green pollution-free fruits and vegetables. 3. High efficiency and energy saving Transparent covering materials shall also be considered during the construction of the greenhouse to ensure fast temperature rise and good lighting in the greenhouse. The temperature difference between day and night in the greenhouse is large. The temperature in the solar greenhouse is usually about 20 ℃ higher than that outside, and the temperature difference at night is only 2 ℃~3 ℃. Using natural light to increase the temperature in the greenhouse can achieve the best temperature for fruit and vegetable planting, greatly improve the quality and yield of off-season vegetables, and achieve the purpose of efficient production and energy conservation.

As an important agricultural production facility and special daylighting building, greenhouse has become an important indicator to measure the quality and service life of greenhouse, including its light transmittance, thermal insulation and durability. At present, the design life of domestic greenhouses is generally 5 to 15 years. Therefore, in order to prolong the service life of the greenhouse, improve the performance effect, and produce high-quality agricultural products, it is very important to do a good job in the daily maintenance of the greenhouse. 1. Daily maintenance of covering materials The roof covering material of the greenhouse has been exposed to the wind and sun for a long time, which is very easy to age, affecting the tightness, light transmission and heat preservation performance of the greenhouse. Therefore, the covering materials on the top of the greenhouse should be maintained every 2 to 3 months. The glass greenhouse and hollow plate greenhouse can be regularly washed with high-pressure water gun on the roof and wall, and the film greenhouse can be cleaned with a broom bound with light articles such as waste cotton battens. The sludge and leaves deposited in the gutter gutter shall also be cleaned. Check whether the glass has cracks, use glass glue to seal, and replace the damaged glass in time. The damaged hollow plate can also be repaired with sealant or adhesive tape. The damaged plastic film can be repaired with special film repair tape. The framework at the contact part between the film and the framework shall be wound with soft cloth or old plastic film to prevent the contact part between the film and the framework from aging and damage due to heat, wind and rain. 2. Maintenance of inner and outer sunshade The internal and external sunshade net is the greenhouse construction equipment with high frequency of use except in winter. The internal and external sunshade net shall be subject to routine maintenance before and after use every year. Firstly, check the transmission system, including the commissioning of the motor, limit switch, stroke, etc., and add lubricating oil to the rack and gear for maintenance. Timely replace the falling and broken curtain support line and curtain pressing line, so that the curtain pushing rod and transmission shaft can move smoothly and the curtain cloth can be flexibly and smoothly expanded. 3. Maintenance of theme skeleton The main structure of greenhouse, including seedling bed support, generally adopts hot-dip galvanized steel pipe as the main load-bearing structure. As the greenhouse has been in the high temperature and humidity environment for a long time, the anti-corrosion ability of the component surface will become one of the important factors affecting the service life of the greenhouse. Therefore, it is also important to regularly maintain the main framework of greenhouse construction and other metal materials every year. Tighten the loose screws at the connection of the components, conduct rust prevention treatment on the welding interface and the parts where the hot-dip galvanized layer is easy to rust due to external forces, use coarse sandpaper to polish, and then apply two layers of anti rust paint for protection.

Greenhouse, also known as greenhouse. A facility that can transmit light and heat (or heat), and is used to grow plants. In the season unsuitable for plant growth, it can provide greenhouse growth period and increase yield, and is mainly used for cultivation or seedling raising of warm vegetables, flowers, trees and other plants in low temperature season. There are many types of greenhouses, which can be divided into many types according to different roof truss materials, lighting materials, shapes and heating conditions. The types of greenhouses include planting greenhouses, breeding greenhouses, exhibition greenhouses, experimental greenhouses, catering greenhouses, entertainment greenhouses, etc; The design of greenhouse system includes heating system, thermal insulation system, cooling system, ventilation system, control system, irrigation system, etc; The greenhouse is just a simple plastic film and skeleton structure, with few internal facilities, which is not as demanding as the greenhouse. Therefore, strictly speaking, greenhouse equipment is more demanding than greenhouse equipment, and more advanced instruments may be used to strictly control temperature.

1. Advantages of multi span greenhouse 1. The multi span greenhouse can control the surrounding environment from a certain point of view. The floor area and volume of multi span greenhouse are relatively large, increasing the volume in the air, thus reducing the indoor temperature. 2. The heating performance of multi span greenhouse is relatively low. As the multi span greenhouse will result in smaller enclosure area and ground distance, resulting in less heat loss, it is necessary to configure a heating system for the multi span greenhouse. 3. Use the land in a wide range. The single span greenhouse greatly reduces the waste of land. 4. The internal space of the multi span greenhouse can be fully used. However, in some common greenhouses, there are some problems such as curved side walls or inclined walls. In this case, the land will be partially vacant, and the goal of perfect land use will not be achieved. However, in multi span greenhouses, this problem does not exist at all. 5. The multi span greenhouse is very flexible in zoning. In order to facilitate the management of multi span greenhouses, a partition wall can be used inside the multi span greenhouses. 6. The multi span greenhouse has the automation function. You can install some planting or water spraying pipes inside it. 2. Disadvantages of multi span greenhouse People living in the north usually do not choose multi span greenhouses to use, because the power consumption rate in winter in the north is very high, and the thermal insulation performance of multi span greenhouses is poor.

Advantages of intelligent greenhouse: 1. Real time data monitoring: crop growth environment parameters, grasp on-site information anytime and anywhere, control on-site equipment anytime and anywhere, automatically adjust various indicators, provide the most "comfortable" and stable environment for crops, form standardized cultivation, and facilitate large-scale replication. 2. Intelligent alarm and early warning: the user sets the appropriate growth environment parameters for crops and sets the priority level. The system will compare the collected real-time environment parameters with the set parameters. When they exceed a certain threshold, the system will give an alarm and early warning by means of sound and light or APP, and notify the management personnel at the first time. 3. Intelligent linkage control: the user can remotely control the device through the computer or mobile phone APP. The internal environment of the greenhouse can also be controlled through automatic linkage of the system. For crops with high environmental requirements, production losses caused by human factors can be avoided. 4. Configuration: The concept of configuration control widely used in the industrial control industry is introduced, and the configuration software based on WEB browser is developed. The user can customize the graphical interface according to the field equipment layout and other information, and bind the sensor and controller to achieve graphical monitoring and control. 5. Intranet penetration: The user network does not need to open a public network. Using the industrial intranet penetration equipment provided by our company, you can establish a safe, stable and fast access channel with the public network to achieve remote access to the public network. If there is no optical fiber network on site, you can directly insert a 4G card and use the mobile/telecom/China Unicom network for communication. 6. HD video: HD cameras and 360 degree video monitoring equipment can be optionally installed, so users can view crop conditions anytime and anywhere through computers or mobile apps. When using 4G network for communication, you need to consider the traffic package. 7. The system runs stably and reliably, and is deployed in the cloud. Users do not need to set up special servers and network systems, saving investment, and software system deployment and maintenance are very simple.

The growth of all things depends on the sun. In the growth of plants, only a few wavelengths of light participate in photosynthesis. Can we use more light? Chinese researchers have proposed a new type of greenhouse covering structure, which realizes the efficient use of solar energy in greenhouse. Relevant research results were published in Energy Conversion and Management. The principle of multispectral utilization of the covering structure of light splitting greenhouse. It is understood that in facility agriculture, 400-780 nm visible light in the solar spectrum can directly participate in the photosynthetic reaction process of crops, which belongs to the photosynthetic effective radiation, while 780-2500 nm near-infrared light is the main factor causing indoor high temperature in the greenhouse, and 30% of the cooling energy consumption is required for high temperature in summer. Therefore, how to effectively use near-infrared light is of great significance for reducing greenhouse energy consumption and improving solar spectral efficiency. How to improve the utilization rate of sunlight in facility agriculture, the research team proposed a new greenhouse covering structure based on the spectral frequency division utilization and the principle of composite parabolic concentrator, and carried out structural optimization and performance analysis. The results show that the covering structure can transform near-infrared light into electric energy storage while passing through photosynthetic effective radiation, which can not only ensure the normal growth of facility plants, but also reduce the energy consumption for greenhouse cooling, The electricity generated can also provide energy sources for the daily operation of the greenhouse. The research was completed by the Facility Plant Environment Engineering Innovation Team of the Institute of Agricultural Environment and Sustainable Development of the Chinese Academy of Agricultural Sciences, and was supported by the National Key R&D Plan, the National Natural Science Foundation of China and other projects. It is reported that the research results provide a new idea for improving the comprehensive utilization efficiency of full spectrum solar energy in greenhouse.

"Greenhouse" is only the name of an industry and does not represent a type of greenhouse. The greenhouse industry is mainly divided into three structural forms: spring and autumn greenhouses, solar greenhouses and multi span greenhouses. These are also the three most common types of greenhouses in the market, but there is no national standard in the actual construction. Because the greenhouse belongs to a temporary building, its construction standards are basically based on industry standards. The dimensions of greenhouse construction are not always designed according to the industry standards, and sometimes the construction site will be adjusted. The principle of actual design and construction is to maximize the use area of soil, which is also the core idea of greenhouse construction. However, the basic requirements of industry standards should also be followed, especially the basic requirements of wind load coefficient and snow load coefficient related to greenhouses. This can ensure the overall quality, reliability and safety of the greenhouse. Basic standard for dimensional design of solar greenhouse ① Basic structure of solar greenhouse As a unique greenhouse type in the north, solar greenhouse is mainly composed of wall, arc skeleton and covering materials (plastic film and thermal insulation quilt). Why is it a unique greenhouse type in the north? It has good thermal insulation. Generally, no heating equipment can be used, and production can also be carried out in winter. Its main wall forms are brick wall and earth wall structure. With the development of science and technology, other forms have emerged, but they are used less. The arc skeleton is mainly galvanized steel or oval pipe skeleton, and there are also flower racks. The covering materials are mainly plastic film and thermal insulation quilt, and its thermal insulation is mainly related to the thermal insulation quilt. ▲ Standard solar greenhouse ② Structural Design of Solar Greenhouse In the design of solar greenhouse, it is mainly reflected in several aspects, including wall thickness and height, length and width. The length and span of the solar greenhouse is the core of the design. The minimum span is 6 meters. Generally, it is 8 meters or 10 meters. The thickness of the wall is mainly related to the thermal insulation, while the height of the solar greenhouse wall is mainly related to the span, that is, the angle of the arc skeleton. The larger the span, the higher the height of the back wall, so that the slope of the skeleton is large. It is more conducive to drainage, and the snow load and wind load coefficient of the construction greenhouse framework. The conventional length is about 100 meters, which is mainly the power problem of the matching quilt winder and film winder. It is also the case that the quilt winder is built at 200 meters long, but the quilt winder needs to be designed separately. Basic standard for dimension design of multi span greenhouse ① Basic structure of multi span greenhouse The main structures of the multi span greenhouse are strip foundation and independent foundation, steel structure skeleton and covering materials (glass or sunlight plate). Its foundation requirements are relatively high, especially for the fixed steel structure. On the basis of the foundation, it is necessary to do a good job of embedded parts, and then bolt the skeleton to ensure the stability of the skeleton. If the covering material is glass, its basic requirements are higher. Because the weight of the glass is relatively large, and the required strength of the skeleton is also relatively high. ▲ Standard multi span greenhouse ② Structural design of multi span greenhouse The multi span greenhouses are basically rectangular, and the requirements in the industry are generally span, the conventional span is 9.6 meters, 10.8 meters, etc., and the maximum span is 16 meters. There is no requirement on the length of multi span greenhouse, as long as the construction site is large enough. In the construction of multi span greenhouses, the smallest has seen more than 300 square meters, and the largest has seen more than 10000 square meters. Summary: The greenhouse design above is the most conventional, but in terms of the development of the whole greenhouse industry and the different needs of the society, there have been irregular greenhouses, and new designs have been carried out according to the needs of customers, but the overall design cost will increase. If the corresponding cost increase due to special design type is acceptable, the special-shaped greenhouse can also be constructed.

Why are the vegetables, melons, and flavors of the crops planted in the greenhouse not fragrant, sweet, and tasteless? Why are there many diseases and poor disease resistance of plants in greenhouses? Why can't the yield be greatly increased with sufficient water and fertilizer? These problems are basically due to a phenomenon that the low concentration of carbon dioxide in the air of the greenhouse causes the crops to have a carbon dioxide "hunger", which cannot meet the needs of crop photosynthesis. 1. Current situation of carbon dioxide planting and application At present, there are more than 50 million mu of greenhouse in China, with an annual output value of about 500 billion yuan, and 80% of the output value comes from winter, spring and autumn. Because of the high output value of vegetables in these three seasons, the greenhouse has been restricted from ventilation for nearly five months, and the carbon dioxide concentration is insufficient, which seriously restricts the output of vegetables. Plants contain more than 95% carbon and water, and less than 5% nitrogen, phosphorus and potassium. Over the past few decades, crops have increased by more than 50% through the application of nitrogen, phosphorus and potassium fertilizers. In the dry matter of plants, organic matter accounts for about 90%, while carbon accounts for about 40% of organic matter, which is a kind of element with more content in plants. The carbon comes from CO2. Therefore, CO2 is of great significance to the biological world. 2. Importance of carbon dioxide As the main material raw material for plant growth, carbon dioxide is one of the key factors affecting plant growth, development and function. It is not only the substrate of photosynthesis, but also the regulator of primary metabolic process, distribution and growth of photosynthates. It participates in a series of biochemical reactions in plants and has a direct impact on plant growth. The increase of carbon dioxide concentration can not only significantly improve the photosynthesis efficiency of plants, but also promote the photosynthesis of plants by expanding the utilization range of light sources. The concentration of carbon dioxide in the air is relatively stable, with little change, generally 0.03% - -- 0.04%. When the concentration is below 25 ℃, with the increase of temperature, photosynthesis is enhanced, and the organic matter created is increased, and the crops show a vigorous growth state; When the temperature exceeds 30 ℃, the organic matter created by photosynthesis is the same as that consumed by crop respiration, or even less than that consumed by respiration, and the crop stops growing. 3. Reasons for lack of carbon dioxide: For the need of heat preservation, greenhouse vegetable production in winter often keeps the greenhouse in a closed state, resulting in a relative barrier between the air inside the greenhouse and the outside air, and carbon dioxide can not be timely supplemented. After sunrise, with the acceleration of vegetable photosynthesis, the carbon dioxide concentration in the shed drops sharply, sometimes falling below the carbon dioxide compensation point (0.008% - 0.01%). Vegetable crops can hardly conduct normal photosynthesis, affecting the growth and development of vegetables, causing disease and yield reduction. According to the measurement, the normal concentration of carbon dioxide in the air is 300-500PPM, and plants absorb carbon dioxide in the atmosphere at any time when they are cut in the open air. However, in the closed greenhouse in winter, in order to maintain a certain greenhouse temperature, there is no large amount of ventilation and air exchange outside the greenhouse. It is difficult for crops to absorb carbon dioxide. As a result, the concentration of carbon dioxide in the greenhouse drops to a critical value, which makes it difficult for crops to have physiological reactions and normal photosynthesis. Crops cannot grow normally. Especially when the crops need to conduct photosynthesis after the sun comes out in the daytime, although the light intensity reaches 1000-3000x, they begin to absorb a large amount of carbon dioxide in this period. If the carbon dioxide cannot be replenished in time, the plants will weaken or stop photosynthesis due to lack of carbon dioxide for a long time, which will inevitably affect the yield and quality of crops. 4. Countermeasures At present, many modern greenhouse greenhouses will be installed with carbon dioxide monitoring points, and manual intervention measures can be taken when the carbon dioxide concentration is too low. It has been proved that the lack of carbon dioxide has become one of the important limiting factors in the production of vegetable in greenhouse. Artificial supplement of carbon dioxide is an important measure to achieve high and stable yield in greenhouse production. At present, there are carbon dioxide generator devices, filling finished carbon dioxide, etc.