Construction Of The Northeast Spring Maize Accumulated Modified Model And Its Application In The Growth Period Forecast

The Northeast region is the largest spring corn production area in China and plays a vital role in ensuring food security.Temperature is an important environmental factor affecting agricultural production.The accumulated temperature is the accumulation of temperature.The accumulated temperature is relatively stable during the growth period of the crop.and it can be used to estimate the growth rate of the crop.Accumulated temperature may be affected by environmental factors,crop varieties and species,showing instability between regions and between years,which in turn affects the application of accumulated temperature in growth period prediction.Therefore,modifying the existing accumulated temperature model to improve the stability of accumulated temperature is of great significance to the better application of accumulated temperature indicators in agricultural production practice.Based on the growth and development of spring maize in different r egions of Northeast China,six meteorological stations of Hailun,Tailai,Dunhua,Changling,Kuandian and Zhuanghe were selected as test stations.By analyzing the correlation between meteorological factors(light,temperature and water)during each growth period and accumulated temperature,the most important meteorological factors affecting the stability of accumulated temperature were screened out.Use this factor to correct the active accumulated temperature model,and then formulate and calculate the modified model.After comparing the modified model with the interannual accumulated temperature stability of the active accumulated temperature and the effective accumulated temperature,the modified model with better stability was obtained.The active accumulated temperature,the effective accumulated temperature and the modified model were used to predict the growth period of spring maize,and the retrospective test and the forecast verification were carried out to evaluate the effect of the modified model on the prediction of the growth period.The results showed that the accumulated temperature and effective accumulative temperature of most sites show an increasing trend with the year;Temperature conditions are the most important factors affecting the stability of the accumulated temperature.At stations with higher latitude and lower temperature,the effect of temperature factor on accumulated temperature is higher.The modified model based on the daily average temperature factor can be regarded as the equivalent accumulated temperature of deformation.The coefficient of variation of the accumulated temperature of the modified model is lower than the coefficient of variation of the active accumulated temperature and the effective accumulated temperature at each station in each development period,indicating that the modified model has a better effect in improving the stability of the accumulated temperature.;In the emergence-tasseling stage and the tasseling-maturity stage,the coefficient of variation of modified model has an average decrease of 0.9% and 1.7% compared to the active accumulated temperature model,and an average decrease of 5.0% and 8.1% compared to the effective accumulat ed temperature model;In the retrospective test,the performance of the modified model was generally better than that of the original model.In the forecast of tasseling period.In the forecast of the tasseling period,the average error of the modified model compared with the actual growth period is reduced by 1.2 days than the effective accumulated temperature.In the matur ity forecast,the average error of the modified model is 3.5d less than the active accumulated temperature error and 8.8d less than the effective accumulated temperature.The 2011-2017 modified model did not significantly improve the forecast accuracy of the spring corn tasseling period,but in the forecast of the mature period,the average error of the modified model was 0.7 d less than the active accumulated temperature error and 6.4 d less than the effective accumulated temperature.The modified model proposed in this paper improves the accumulated temperature stability of the effective accumulated temperature and active accumulated temperature to a certain extent,and has achieved good results in the application of crop growth period prediction.It is helpful to provide a basis for agricultural production measures and provide new ideas for the research of crop growth period forecast.