What Are Greenhouse Crops?

Greenhouse (greenhouse), also known as greenhouse. A facility that can transmit light and keep heat (or heat) to cultivate plants. In the unsuitable season for plant growth, it can provide greenhouse growth period and increase yield. It is mostly used for plant cultivation or seedling cultivation of vegetables, flowers, forests 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.

Greenhouse

Greenhouse (greenhouse), also known as greenhouse

An indoor greenhouse cultivation device including a planting trough,

Greenhouse ^[1]

As society continues to progress, the traditional agricultural production model can no longer meet the needs of the development of modern civilization, and new types of facility agriculture are sought after by the industry. The so-called agricultural equipment is actually a greenhouse facility. It is not limited by time and space. It can carry out agricultural production in special environments such as plateaus, deep mountains, and deserts.

China is a large agricultural country. Farmers account for more than half of the total population. The space for agricultural innovation and application is unlimited. The agricultural equipment industry has gone from behind the scenes to before the stage. Throughout the domestic greenhouse industry, large and medium-sized enterprises are uneven, and the quality of greenhouse projects to be implemented is naturally very different.

In order to allow organizations that intend to develop facility agriculture to better select greenhouse project service providers, a systematic survey of the greenhouse industry has been conducted. The quality control of greenhouse projects is mainly divided into material control, technical control, construction control, and after-sales control. Four aspects.

As the source of the greenhouse project, materials must be well controlled by the selection of materials. For example, the steel components used in greenhouse projects are used to process and derust high-quality steel. After hot-dip in a professional galvanizing plant, the quality inspection department will test again and will be shipped to the site for use after passing the test.

Technical controls

The project team has professional designers. Before the start of each project, the greenhouse project manager conducts detailed project training for the engineering and technical personnel, takes out the difficulties and points of the project, and discusses in advance the areas that are prone to errors. Engineering and technical personnel have a good idea before the start of the project. After the project is started, it is implemented according to the predetermined plan and steps, which effectively avoids errors during the construction process and also ensures the quality of the entire project.

Control of the construction process

Each greenhouse project should be equipped with a professional technical engineer. During the implementation of the project, the engineer serves the entire construction process. Ensuring that construction personnel strictly follow the drawings and specifications.

In addition, the quality of project implementation is also very different, and the overall quality control is mainly the above four aspects. ^[2]

Spring greenhouse

1,

Internet of things technology

In fact, the Internet of Things technology is the aggregation and integration of various sensing technologies, modern network technologies, and artificial intelligence and automation technologies. In a greenhouse environment, a single greenhouse can use the Internet of Things technology to become a measurement control area of a wireless sensor network. Different sensor nodes and nodes with simple actuators, such as fans, low-voltage motors, valves, etc., with low operating current, are implemented. Organization, forming a wireless network to measure substrate humidity, composition, pH value, temperature and air humidity, air pressure, light intensity, carbon dioxide concentration, etc., and then through model analysis, automatically regulate the greenhouse environment, control irrigation and fertilization operations to obtain plant growth Best conditions.

For agricultural parks with greenhouses, the Internet of Things can also realize automatic information detection and control. Equipped with wireless sensor nodes, each wireless sensor node can monitor various environmental parameters. By receiving the data from the wireless sensor convergence node for storage, display and data management, it can achieve the acquisition, management, analysis and processing of all base test point information, and display it to users in each greenhouse in an intuitive chart and curve manner. At the same time, according to the needs of planting plants, various sound and light alarm information and SMS alarm information are provided to achieve intensive greenhouse and network remote management.

In addition, IoT technologies can be applied to different stages of greenhouse production. In the preparation stage of the greenhouse, various sensors can be arranged in the greenhouse to analyze the internal environment information of the greenhouse in real time, so as to better select suitable varieties. In the production stage, employees can use the Internet of Things technology to collect the temperature in the greenhouse. Various types of information such as temperature, humidity, etc. are used to achieve fine management. For example, the opening and closing time of the shade net can be sensed and controlled according to the temperature and light in the greenhouse. The heating system startup time can be adjusted based on the collected temperature information. After the product is harvested, you can also use the information collected by the Internet of Things to analyze the plant performance and environmental factors at different stages and feed it back to the next round of production, so as to achieve more accurate management and obtain higher quality products.

It is advisable to surpass the frozen layer. The design of the greenhouse foundation is based on the geological structure and local climatic conditions in cold regions and soils with relatively loose soil foundations. Greenhouses that cannot be produced throughout the year are deeper than greenhouses that are produced throughout the year. Ground foundations filled with wool or river stones must be grounded with 2030 cm thick beams, and walls must be built on the ground beams. The walls must be insulated. The insulation interlayer is filled with insulation materials such as benzene board and perlite. Expansion joints are recommended for walls with a length of more than 70 meters. The rear wall of the greenhouse should have certain ventilation windows according to the nature of the greenhouse for ventilation in winter. Before the masonry and capping of the wall of the rainbow greenhouse, the arch embedded parts should be lowered for arch installation. The height of the greenhouse wall is determined according to the span of the greenhouse. Generally, the height of the rear wall of the greenhouse is 2.5 meters. A height of 7.5 meters across the back wall of the greenhouse is 2.3 meters.
When selecting the site, try to choose a flat plot. The location of the greenhouse is very important. The groundwater level should not be too high. Avoid high mountains and buildings that block light. For planting and breeding users, sheds should not be built in polluted areas. In addition, areas with strong monsoons should consider the wind resistance of selected greenhouses. Generally, the wind resistance of greenhouses should be above level 8.
The orientation of the greenhouse has a great influence on the heat storage capacity in the greenhouse, and for the solar greenhouse. Based on experience, the greenhouses in the south are better oriented westward. The westerly angle is preferably 510 degrees. This allows the greenhouse to accumulate more heat. If multiple greenhouses are built, the spacing between the greenhouses should not be less than the width of one greenhouse.
The direction of the shed is that the shed heads are on the north and south sides, respectively. This orientation allows the crops in the greenhouse to be evenly distributed.
Greenhouse wall materials can be used as long as they have good thermal insulation and heat storage capacity. The inner wall of the greenhouse emphasized here must have a heat storage function, and the masonry of the solar greenhouse must be adapted to local conditions. To store heat. At night, this heat is released to maintain the temperature balance in the shed. Brick walls, cement plastered walls, and earthen walls all have heat storage capacity. The wall of the greenhouse generally adopts a brick-concrete structure.

Formation of toxic gases in greenhouses and preventive measures

Cultivation of vegetables in plastic greenhouses often reverts to improper fertilization methods, neglecting ventilation and ventilation, causing excessive toxic gases in the shed, damaging vegetables, and often being misdiagnosed as diseases, resulting in failure to achieve the final effect.
1. Nitrogen, due to the application of excessive urea, thorium sulfate and other fast-acting fertilizers, or improper fertilization methods, if undecomposed organic fertilizers are used to decompose and produce ammonia under high temperature conditions in the greenhouse, it will harm vegetables and cause leaf edge tissues Water-stained spots, with the whole leaf dying in severe cases. It is often misdiagnosed as frost disease or other diseases. Vegetables sensitive to ammonia include cucumber, tomato, and zucchini.
2. Too much ammonium nitrogen fertilizer applied once by nitrous acid gas will reduce the effect of some bacteria and cause local acidity of the soil. When the pH value is less than 5, nitrous acid gas is generated, which can cause white spots on vegetable leaves, and the whole leaf will become white and die. It is often misdiagnosed as powdery mildew. Vegetables sensitive to nitrous acid gas are eggplant, cucumber, zucchini, celery , Chili, etc.
3. Ethylene and chlorine gas If the quality of agricultural film or mulch film is poor, or if there is residual mulch film in the ground, it will be exposed to sunlight. Under high temperature conditions in the shed, it will easily volatilize and produce harmful gases such as ethylene and chlorine gas. When the concentration reaches a certain level, the leaf edges or veins of vegetables can turn yellow, and then turn white. In severe cases, the whole plant dies. It is often misdiagnosed as bacterial angular spot disease, and it is particularly harmful to cucumbers.
In addition, heating and heating in winter will generate toxic gases if the fuel is not fully burned, and the lack of ventilation will cause excessive accumulation of carbon dioxide. Affect vegetable production.
Two preventive measures:
1. Reasonable fertilization. The organic fertilizer applied in the greenhouse must be fermented and scorched, the fertilizer must be high quality, and urea should be mixed with phosphate and calcium. The base fertilizer should be applied 20 cm deep, and the depth of topdressing fertilizer should be about 12 cm, and watered immediately after application.
2. Ventilation. In sunny and warm weather, ventilation should be performed in conjunction with temperature adjustment, and ventilation should also be performed in rainy and snowy weather.
3. Use safe and non-toxic agricultural film and mulch film to timely remove waste plastic products and their residues in the shed. ^[5]

1.Irrigation method

Drip irrigation is to drip a drop of water evenly and slowly into the soil near the root zone of the plant through a dripper installed on the capillary. With the help of the capillary force of the soil, the water infiltrates and diffuses in the soil for absorption by the plant root And utilization, the soil moisture is always in an unsaturated state, making the soil loose and airy, which is conducive to plant growth. The principle of using hose drip irrigation is to irrigate less frequently, with an irrigation volume of 7-15 cubic meters / mu. Specific methods: First, when filling water, first close the straw valve of the fertilizer, then open the valve to the maximum, and then connect the pressurized water source to fill the water. Switch, the filter is fixed at the bottom of the fertilizer solution bucket, and the fertilizer can be fertilized by connecting the water source. After the fertilization is completed, the switch on the suction pipe must be turned off, and the valve must be opened to continue irrigation, so as to flush the residual fertilizer in the pipe.

2, matters needing attention

(1) Install a drip irrigation system to ensure that the control area of each section of the supervisor basically does not exceed half an acre of land. At the same time, the ground in contact with each hose is level to ensure smooth water flow;

(2) The holes in the drip irrigation belt are usually laid upwards and covered with plastic film. If the film is not covered, the holes of the drip irrigation belt can be laid downwards;

(3) Use a clean water source. There must be no suspended matter larger than 0.8 mm in the water, or a net filter must be added to purify the water. Filters are usually not used when using tap water and well water;

(4) Be careful not to scratch or puncture drip irrigation tapes or supervisors during installation and field operations;

(5) After fertilization, water should be irrigated for a period of time to prevent the accumulation of chemicals at the orifice to block the orifice;

(6) In order to prevent the accumulation of sediment and other impurities in the pipe and cause blockage, release the drip irrigation belt and the tail of the main pipe one by one and increase the flow of flushing;

(7) When changing crops, remove the equipment and keep it in a cool place.

The greenhouse construction site should be free of obstacles such as large stone blocks, underground pipelines, and underground facilities within a depth of one meter below the ground. The builder should do the five connections and one leveling work according to the requirements of the greenhouse construction, that is, water, electricity, access roads, and telephone calls. , Drainage, leveling and compacting the site. Before obtaining the site geological description or survey report, the construction unit shall temporarily design and make estimates based on the allowable bearing capacity of the supporting soil layer 80kpa and the stable underground water level at 1m below ± 0.000. The depth of the independent point foundation is about 0.5m below ± 0.000, and the independent foundation is used inside the greenhouse. A 0.5m high brick skirt is set around the greenhouse, of which about 0.5m is below ± 0.000, and 0.50m above ± 0.000. Buried anchor bolts are used to connect the upper structure columns, and the inside and outside of the wall skirt are plastered with cement mortar; 80cm wide concrete scattered water is set around the greenhouse; and drainage ditches outside the greenhouse are installed outside the facility. The drainage ditch around the greenhouse was built by the owner. The design is based on the national standard "Code for Design of Building Foundations" (GBJ50007-2002). If the geological description provided by the construction party does not match the actual situation (such as the survey report), then the foundation design will be carried out, and the design calculation and estimate of the greenhouse foundation will be adjusted accordingly.