STUDY OF LOW TEMPERATURE DAMAGE PREDICTION APPLICATIONS IN EN, CHINA BASED ON A SCALING-UP MAIZE DYNAMIC MODEL

A scaling-up maize dynamic model in EN, China is established, including an improved heat unit development model and crop parameters in the certain regions based on the maize field experiments data and predecessors' studies on crop simulation models. The development and growth processes are simulated for 12 stations using daily weather data for 40 years (1961—2000). The index for low temperature damage is defined by the days of tasseling postponed. The years with low temperature damage and the related reduction of yield are analyzed using the index. The development and growth processes in the grids with 0.25o×0.25o are simulated for the year with typical low temperature damage and for mean climate condition in 40 years. The experiment on prediction method of low temperature damage using maize simulation model combined with regional climate model is carried out. The main conclusions are as follows: (1) The model of development stage well simulates maize development stages and the response of development stages to low temperature damage. Using the index for low temperature damage defined by the days of tasseling postponed, the degree of low temperature damage is estimated. The results are very well and are conformed by historical cases. (2) The model can basically simulate responses of maize biomass to low temperature damage; but the parameters of cultivar should be calibrated by more measured experiment data, and the model will be modified further. (3) It is a resolution to scaling-up application of crop models to determine the crop parameters in these areas and to apply GIS. (4) The method for scaling-up maize dynamic model is of more mechanism and explanatory. Running maize model, according to low temperature damage index and output of regional climate models, it is easily to simulate and predict occurrence degree of low temperature damage.