Forewarning technology and application for monitoring low temperature disaster in solar greenhouses based on internet of things

The Internet of Things has been wildly used in solar greenhouse. Most applications focus on facilities modern greenhouse environment monitoring and regulation, product traceability, and pest remote diagnostics. In fact, facility agriculture uses different methods to change microclimate in greenhouse to help crop grow anti - seasonally. This study focused on the Internet of Things (IOT) application in reducing the influence of low temperature disaster on solar greenhouse production in North China caused by strong cooling and successive overcast weather in winter and spring. We installed several sensors in greenhouse including air temperature, relative humidity, soil temperature, radiation (or light intensity), crop camera platform with synchronization photography, which composed the sensing layer of IOT. The equipments transferred data every 10 minutes to the server in our office. An application was developed to transfer data through socks programming, query and analyze data, and retrieve greenhouse cryogenic information. Data from different manufacturers are changed into a unified format, then SQL server 2000 sp4 is used to store data. A microclimate monitor data receiver software, based on GIS, was also developed to help people display and analyze data. A cryogenic disaster indicator for cucumber and real-time microclimate data analysis and processing system were established, which can provide low-temperature disaster warning. For example, if the cucumbers are planted in solar greenhouses during the flowering and fruiting period, and the lowest temperature outside is lower than -10℃ and highest temperature outside is lower than -3℃, the cucumbers will stop growing or become damaged. Because most greenhouses share a few structures, when we make a low temperature disaster warning towards one kind's structure, it can be sent to the greenhouse manager group who owned same type greenhouse structure. The results were available via SMS (Short Message Service), LED/ LCD electronic display, website, and voice calls. We developed professional weather service website for real-time data and image display, microclimate data analysis and disaster warning in the greenhouse. We used flash/html5 to display data dynamically. When the greenhouse temperature goes down to threshold, people receive a warning by SMS. At the same time, the application platform triggers intelligent switch through SMS to start the heating equipment, and then prevents the crop from low-temperature disaster. We used an electric heater as heating equipment in this test. The temperature in heater outlet was stabilized at 7℃ and wind speed stabilized at 3m/s. The results show that temperature in the test greenhouse is 4.2℃ higher than in the reference greenhouse without heating. The average lowest temperature in test greenhouse is 4.5℃ higher than reference greenhouse. The average temperature is 4.3℃ higher than the reference in cold weather and 4.5℃ higher in successive overcast weather. Because temperature distribution in space is uniform, it will not affect the uniformity of the crop population growth. This study effectively solved the low-temperature disaster monitoring and early warning problem in Tianjin. Using Internet of Things and cloud computing technology, it helped users to acquire relevant information through simple receiving terminal that could be used for disaster prevention. Effective monitoring and intelligent remote management in the groups of solar greenhouses will change the traditional management mode and improve management efficiency and capacity of calamity reduction.