Design and experiment of rice program control germination system in cold region based on internet of things

Abstract: Rice is one of main food crops in the world, and rice yield accounts for 37.3% in total food yield in China, so the technology of rice yield increase becomes a research hot point. Seed soaking and pregermination technology is an important technology in rice cultivation, especially in cold region of China. Rice is very susceptible to frost damage, and therefore rice needs an accumulated temperature compensation to prolong rice growth stage. Rice seeds can acquire effective accumulated temperature of 100 ℃ through seed soaking and pregermination technology. The whole process of seed soaking and pregermination has 3 stages: Soaking seeds, seeds budding and seeds germination. The temperature range of soaking seeds stage is from 11 to 13 ℃, the second stage is seeds budding process which needs a temperature range from 31 to 33 ℃, and the third stage is seeds germination process which needs a temperature range from 26 to 28 ℃. However, in the present condition, there are several serious problems in large-scale rice soaking and pregermination in cold region: The upper and lower water temperatures are not uniform during the soaking process, and seeds aerobic respiration is not good in large-scale sprouting tank. These problems are easy to cause lower budding ratio of seeds or thin weak seedlings. Further, these problems will cause severe loss in yield and quality of rice. To solve these problems, the activation mechanism of seed germination was studied firstly. This mechanism included the effect of soaking temperature and time on the physiological activity of rice seeds. Secondly, temperature and humidity monitoring system of sprouting tank was introduced based on internet of things technology. This system included 3 parts: Infrastructure used for placing the seeds, electric heater, circulation pipe line, solenoid valve, and so on; intelligent monitoring system used for production data acquisition, data display, data storage and production equipment control based on sensor technology and computer technology; remote monitoring and data service system used for remote virtual control of production equipment and managing of multiple production bases based on network technology. This system could be used for automated management of sprouting tank environment parameters. Thirdly, we divided the temperature field into 3 layers: Upper layer, middle layer and under layer, and we simulated the temperature field of sprouting tank with MATLAB software. The simulation results of temperature field showed that control accuracy of system was high, and the temperature uniformity was good in the sprouting tank. The results of sprouting experiment also showed that the germination rate could reach 97.79%, the degree of buds uniformity and haleness were improved substantially, the temperature control accuracy could reach ±0.2 ℃, and the water level control accuracy could reach ±0.3%. This research provides a kind of new technical support for the improvement of the rice soaking and pregermination, and at the same time, this technology shows better social and economic benefits.