Internet of Things Helps Agricultural "Smart Greenhouse" Greenhouse Transform into Smart Factory

In the construction of protected agricultural greenhouses in China, there are still many problems such as low degree of networking, backward operation and management, and the level of environmental regulation needs to be further improved, which restricts the improvement of the overall production efficiency of protected agricultural greenhouses. In order to solve a series of problems in greenhouse production, based on the Internet of Things technology, the application design of the Internet of Things technology in greenhouse production was discussed, and an intelligent control system for greenhouse production was developed. It is hoped that this study can promote the scientific management of greenhouse in protected agriculture and promote the development of greenhouse in a scientific, networked, intelligent and automated direction.

Generally speaking, the Internet is a new generation of information technology, and the Internet of Things integrates the Internet, sensor networks, sensor elements and intelligent information processing. The Internet of Things originated from the networked radio frequency identification system, and gradually matured. Today, the academic community has not reached a unified understanding of the concept of the Internet of Things, and experts and scholars have different opinions on the definition of the Internet of Things. We generally agree that the Internet of Things is a wired and wireless communication mode, which collects object information by means of sensors, satellite positioning and radio frequency identification. And upload this information to the internet, so as to achieve accurate positioning, identification, monitoring and management of objects in real life. The wide application of Internet of Things technology in agricultural production is mainly reflected in agricultural services, agricultural management and agricultural production and operation. From the characteristics of Internet of Things technology, Internet of Things technology can be divided into transport layer, perception layer and application layer. Each technical layer plays its own role, among which the first is the perception layer. As the foundation of agricultural Internet of Things, perception layer provides more reliable data support for application layer and transport layer. Specifically, the perception layer comprehensively collects the information of articles in daily life through satellite positioning, remote sensing technology and intelligent sensors, such as crop growth information, soil information, environmental information, product logistics information and so on. Second, the transport layer. The intermediate link transport layer of agricultural Internet of Things uses Internet, mobile communication network, local area network, etc. Realize the transmission of object data information collected by the perception layer, and transmit the data to the application layer safely and stably. Similarly, the data processed by the application layer is also fed back to the perception layer equipment terminal through the transmission layer, which provides guidance for agricultural production. Third, the application layer. The application layer can be said to be the top link of the whole agricultural Internet of Things, including agricultural product traceability, field planting, facility agriculture, facility gardening, agricultural product logistics and other fields. In the application layer, data fusion, data management, data early warning, intelligent control, diagnosis and reasoning are realized, which promotes the realization of more intelligent, efficient and intensive agricultural production process.

Environmental parameters and characteristics of greenhouse in protected agriculture Generally speaking, whether horticultural crops can grow healthily depends on their own genetic characteristics on the one hand, and is closely related to the growth environment on the other. Environmental factors mainly include temperature, humidity, light, gas and so on. In greenhouse, the quality and yield of crops can be effectively improved by controlling various environmental factors at an appropriate level.

First, the temperature. Temperature is an important factor affecting respiration and photosynthesis of horticultural crops. Each crop has a suitable temperature range, which meets the requirements of "three basic points". The "three basic points" specifically include the lower temperature limit, the upper temperature limit and the optimum growth temperature. For example, for photosynthesis, the most suitable growth temperature range of crops is 20℃ ~ 25℃; For respiration, the most suitable respiration temperature range for crops is 36℃~40℃. It should be emphasized that a certain temperature difference between day and night should also be maintained for the environment of protected agricultural greenhouses. So, how to control the temperature of agricultural greenhouses in protected areas? Under normal circumstances, we mainly use electric heating, hot air heating and hot water heating for heating, and our factory uses water evaporation, shading and ventilation to cool the environment. If necessary, because there is a certain correlation between temperature and humidity, both heating and cooling will lead to the change of humidity in the greenhouse, and the influence of humidity change on crop growth should be considered.

Second, the humidity. Humidity can be said to be the most important environmental factor affecting crop growth. Generally speaking, the water content of crops is 60%~80%, and the physiological processes of crops are almost inseparable from the participation of boiling water, such as transpiration, respiration and photosynthesis. For protective agricultural greenhouse, the humidity of its internal environment is determined by soil humidity and air humidity. The greenhouse itself is a closed microenvironment, and we often treat it to reduce humidity. In general, we can remove excess moisture in the air by ventilation, and we can also use certain adsorption materials to reduce the humidity of the air. Third, the intensity of light. Photosynthesis of plants is inseparable from light, and the rate of photosynthesis changes with the change of light intensity. As we all know, for crops, each crop corresponds to a light saturation point. Below this light saturation point, the growth of crops is limited, while above this light saturation point, even if the light intensity increases, the photosynthesis of crops will not accelerate. The optimum light intensity range of most crops is 8000~ 12000lux. We often use shading and supplementary light to make crops grow in the optimum light intensity range as much as possible. The artificial light source is used to artificially extend the illumination time or increase the illumination intensity to supplement the light, and the sunshade net is used to block the light.

The design of greenhouse intelligent control system in protected agriculture is based on various environmental parameters of greenhouse. The architecture of Internet of Things designed in this paper includes perception layer, transport layer and application layer. Ethernet is connected to local area network, which realizes the automation, intelligence and scientific control of greenhouse and greatly improves the efficiency of agricultural production.