Study On Drought And Flood Loss Of Summer Maize Based On GECROS Model In Huanghuaihai Plain

Agricultural meteorological disaster is one of the main factors restricting agricultural development in our country. On agriculture meteorological disasters to evaluate the effects of the analysis is one of the hot research topic in China. At present, the impact of agricultural meteorological disaster assessment technology is given priority to the mathematical statistics method in domestic. Though the method is simple, easy to statistics, but its evaluation result have close relationship with observation data of the sample length. The biological climate variables and extrapolation effect on region and year is poor, and the degree of quantitative evaluation and dynamic tracking ability is lack. Although using the method of crop model is less now, the model mechanism remains to be improved and regional evaluation effect also needs to be strengthened, but it may overcome the weakness about statistical method of the variable biological significance indeterminacy and extrapolation effect badly, and provides an effective method for drought and flood disaster loss assessment business.In view of the Huang-Huai-Hai region during the frequent drought and flood of summer maize growth throughout the years, with summer corn as the research object, on the basis of drought and flood water control experiment and field disasters investigation. This research uses the GECROS model of Wageningen development for quantitative evaluation of maize drought and flood disasters. On the basis of the single point localization and regional simulation application, this paper carry out drought index and sensitivity study of different maize development stages upon crop growth model to determine the sensitive degree and time of maize drought and flood. And use meteorological data to drive crop growth model for the drought and flood damage assessment to provide the basis for drought and flood disaster loss evaluation business. Main conclusions:(1) The development parameters were defined by maize development data over years, development parameters calibration, and back and extrapolation simulation test. According to the biological significance of GECROS model of crop growth parameters and sensitivity analysis, the crop growth parameters adjustment was determined. Part parameters use the default values, another part were re-estimated by the actual biomass data, so as to determine GECROS growth parameter values. Simulation test results show that GECROS model can reflect the Huang-Huai-Hai region of summer maize under different moisture conditions for growth and development process, which lay a foundation for realizing regional drought and flood disaster assessment application.(2) The each site final production of Huang-Huai-Hai region were simulated by GECROS model under the actual precipitation condition. The influence of precipitation change on maize yield and the model sensitivity of the drought and flood were analyzed by changing the typical drought and flood years of actual precipitation to simulate the final production. And the further research on final yield impacted by the precipitation changes in different periods was determined to the sensitive stage of maize affected by the drought and flood. (3) The ground total weight and yield were simulated by GECROS, as the factors indicators of the influence of drought and flood disasters on crop production. And another indicator to distinguish the actual drought and flood was determined by anomaly of precipitation during summer maize growth. The meteorological data and soil data of the Huang-Huai-Hai region multiple sites in1961to2010were used to run GECROS to simulate the daily ground total weight, kernel weight, and yield under the actual and potential precipitation conditions. The drought and flood losses evaluation indicators were established by total weight and yield decrement of each growth stage, as well as the corresponding stage of the precipitation anomaly percentage.(4)According to the frequency of the disasters, which is the drought and flood of qualitative data, the different levels of drought and flood indicators and the threshold value at all levels were determined. On the basis, the history generalization of the different drought and flood grade of each indicators partition was inspected, so as to lay a foundation for maize drought and flood disaster assessment of Huang-Huai-Hai region. At the same time, combining with the drought and flood levels at different development stages, the different maize growth stages of drought and flood disaster were assessed.(5) GECROS model simulation results were used for regional assessment, which is combined with Huang-Huai-Hai maize comprehensive drought and flood indicators. Through comprehensive indicators test, the drought and flood situation of maize growth period can be well reflected. And selecting the individual year to compare the simulation results and the actual situation on whole growth period, the reasons for the possibility of some difference were analyzed. In addition, the spatial distribution of drought and flood disaster situation and the trend along with the change of reproductive process at different growth stages of individual years were analyzed.