| Wheat and maize are the main food crops in China,accounting for 55.3% of the total output.In recent years,in order to increase the per unit area yield of grain,excessive use of fertilizers and unreasonable field management measures of nitrogen leaching,makes the agricultural non-point source pollution risk to the wheat corn producing areas continue to grow,so you need to build the nitrogen leaching resistance of wheat major corn producing areas suitable for control mode,in order to achieve production and environmental benefits of a win-win situation.The traditional field technology model combination experiment is greatly affected by natural conditions and has a long period.It is difficult to obtain satisfactory results in a short time.Therefore,it is very important to use crop growth model for computer optimization simulation on the basis of field experiment.In order to select the best nitrogen loss control mode in the main Wheat and Maize producing areas,this thesis used Python programming language,My SQL database and PyQT5 front-end module,and adopted the Ceres-Wheat and Ceres-Maize growth models integrated with Agricultural Transfer Decision Support System(DSSAT).A decision support system for controlling nitrogen leaching resistance in major wheat and maize producing areas was established In addition to the simulation file creation,simulation results reading and visualization,simulation precision analysis,model calibration and other functions,the system also realizes the following two parts:(1)In order to solve the complex problem of meteorological data collection of agricultural models,the historical meteorological database for 1951-2020 in the main wheat and maize producing areas was established,and the automatic meteorological data processing module was developed to realize the visual display of the daily maximum temperature,daily minimum temperature and monthly rainfall of the meteorological data in the selected period.(2)In order to solve the limitation of simulated year of agricultural model,the future meteorological database of RCP4.5(medium emission)and RCP8.5(high emission)with different concentrations of carbon dioxide emission scenarios for2021-2100 was established,and the simulation and prediction module of future crop growth was developed.This module can provide maximum temperature,minimum temperature,average temperature,rainfall and solar radiation in the whole year or crop growth under RCP4.5 and RCP8.5 scenarios in six periods of 2001-2020,2021-2040,2041-2060,2061-2080,2081-2100 and 2020-2100 The change trend of the breeding period was realized to predict and analyze the future trend of grain yield,aboveground biomass,grain N content at maturity,total N content at maturity,N utilization rate,N leaching,cumulative ammonia volatilization and so on under the two climatic scenarios.This system can not only simulate the technical effects of various models of nitrogen leaching resistance control,but also predict the performance of different models under future climate change,which provides theoretical support for the selection of models of nitrogen leaching resistance control in main production areas. |
