Research On Simulation Of Rice Brown Planthopper Occurrence And Development Based On System Dynamics Model In Anhui Province And Its Application

Large-scale rice brown planthopper had occurred in our country since the 1970s, which becomes the primary insect pest during rice production. As a long-distance migratory flow pests, its degree of occurrence & development is associated with the time and number of adult pests that moved into, weather conditions, field microclimate, rice nutrition, natural enemies, local prevention methods and so on. So its descriptive model has complex systems’features, such as dynamic, continurity, nonlinear, multi-variable, and multi-feedback and so on. Currently, the prediction methods of rice brown planthopper occurrence & development are based on static mathematical modeling and relative Influencing factor analysis methods, which could not better describe the features of rice brown planthopper occurrence & development on dynamic, continurity and complexity, and the prediction accuracy is not high.With the system dynamics method herein, We study the causal relationship between the various factors of rice brown planthopper occurrence & development from the whole-local perspective in this paper, establish the causal relationship diagram of factors and flowchart of system dynamics on rice brown planthopper occurrence & development in Anhui. Combined with discrete diversified portfolio computing method, we also have established and implemented a system dynamics simulation model on rice brown planthopper occurrence & development in Anhui. Based on the above work, we verified the feasibility, effectiveness and accuracy of simulation model by outbreak data of rice brown planthopper in 2005, Anhui province.The main contents of this paper are as follows:1, we have done an in-depth research and analysis about Anhui plant protection system business processes, and have built an underlying database and a knowledge base of pest in Anhui province, then we have finished the design and implementation of Anhui crop pest monitoring and early warning platform based on vs.net platform.2, we have reorganized the pests’data and weather data which from "Anhui crop pest monitoring and early warning platform" that collected over 20 years, and have preprocessed these data by mathematical methods, such as cleansing data, missing data interpolation and normalized.3, we used system dynamics method to study the process of the occurrence & development on rice brown planthopper in Anhui, and established the causal relationship diagram of factors on rice brown planthopper occurrence & development in Anhui from the whole-local perspective. Based on the analysis of the relationship between causal factors, the rice brown planthopper occurrence & development in Anhui were classified as "migratory flow subsystem", "prevention subsystem", "field microclimate subsystem" and "host subsystem" four subsystems, and we constructed the causal relationship diagram and flowchart of system dynamics for these subsystems, respecively.4, combined with discrete diversified portfolio computing method, we have established a system dynamics simulation model on rice brown planthopper occurrence & development in Anhui, and set up the basic input parameter of simulation model. Combined with information technology, we have done several simulation studies of rice brown planthopper occurrence & development by this simulation model.5, Based on the above work, we have verified the feasibility, effectiveness and accuracy of simulation model by outbreak data of rice brown planthopper in 2005, Anhui province. Meanwhile, relied on this simulation model, we have got different simulation results on rice brown planthopper occurrence & development in Anhui under different strategies in 2005.With the support of the Ministry of Agriculture Agricultural Research nonprofit special(nyhyzx07-048) and under the Plant Protection Station of Anhui province, the system dynamics method is applied to the rice brown planthopper monitoring and early warning, and for predicting the degree of rice brown planthopper occurrence & development, reducing the loss of rice production, building a more scientific and objective monitoring, early warning and prevention system, it has a certain research value and practical significance.