Organic Vegetable Diseases Forecasting Model And Carbon Assimilation Estimate Model Based On System Dynamics And Internet Of Things Technology

Based on the theory of system dynamics and vensimPLE modeling software as a technology platform, this paper established three organic vegetables diseases forecasting and warning models and carbon sequestration estimation models, taking cucumber bacterial spot, tomato virus disease and cowpea blight as test subjects, using the dates of environmental factors(air temperature,humidity, soil temperature, light intensity, etc), the data of disease demange and LI-6400 measured data. The main findings are as follows:(1) The results of the three organic vegetables carbon sequestration capacity showed that: the diurnal variation curve of photosynthetic rate of the three vegetables was a bimodal curve. The net photosynthetic rate rise since 8:00 in the morning, reaching a maximum at 11:00 or 12:00.and the second peak occurs at 15:00 and 16:00 in the afternoon. The daily net carbon sequestration capacity of tomato was weakest in the late fruiting stage and strongest in the flowering stage. The order of the net carbon sequestration capacity of cucumber is vine growing stage, the peak fruiting stage, the late fruiting stage and the seeding stage. The order of the net carbon sequestration capacity of cowpea is the peak fruiting stage, the vine growing stage, the late fruiting stage and the seeding stage. The maximum value of the net carbon sequestration in the peak fruiting stage is26.09 g ? m-2 ? d-1, the mumimum in the late fruiting stage is 15.54 g ? m-2 ? d-1.(2) The results of the SD model to predict disease show that the virus disease started to demange tomato leaf on August 10, followed by the further development of the disease, the incidence got its first peak(39.02%) on August 25, and declined in the early September. Then with gradually increasing, the incidence got the second peak at 84.4% on August 25. Cucumber bacterial spot didn’t appear in the seeding stage and the vine growth stage but in the early flowering stage, then the incidence gradually increased. Between the June and the July, the incidence of bacterial spot fluctuated upward trend, rising rapidly after June 15 and declined after July 15. With the increasing in humidity and keeping in temperature of air, the incidence quickly increased to a maximum value of 37.9%. The seeding death rate of the cowpea had been showing a steady upward trend in the seeding stage. After the seeding stage, the plants had a strong resistance to the blight; the death rate was not increased.(3) The results of organic vegetables sequestration estimation show that: the tomato growing in a standard greenhouse(667m2) can assimilate about 0.682 t CO2 in its whole growth cycle estimated by the SD model. Cucumber can assimilate about 1.168 t CO2 in its whole growth cycle in the same are. The cowpea can assimilate about 1.168 t CO2. The occurrence of viral diseases,make tomato lose 40.2% of carbon sequestration; cucumber carbon sequestration loss rate was9.26% causing by bacterial angular leaf spot; cowpea carbon sequestration loss was 51.5%causing by blight. On a healthy state, the total sequestration size of the three vegetables was followed by cucumber> cowpea> tomatoes.