Abstract: 【Objective】This paper explores the dynamic prediction model and characteristic parameters of dry matter and nitrogen accumulation in summer maize with different nitrogen supply levels based on effective accumulated temperature, in order to provide a theoretical basis for using effective accumulated temperature to predict summer maize dry matter and nitrogen accumulation.【Method】This study is based on a two-year field experiment in Langfang, Hebei Province (2019-2020), using Zhengdan 958 as the test material, and using the normalization method to fit the dry matter and nitrogen accumulation of summer maize with different nitrogen supply levels through model screening. Based on the normalized Gompertz model of effective accumulated temperature after sowing, and using the growth rate curve and its characteristic parameters, the dry matter and nitrogen accumulation characteristics of summer maize were quantitatively analyzed.【Result】(1) Under the experimental conditions, when the amount of phosphorus and potassium fertilizer is appropriate, the maximum dry matter and nitrogen accumulation of summer maize continue to increase with the increase of nitrogen application rate.(2) The normalized Gompertz model of summer corn dry matter and nitrogen accumulation established with effective accumulated temperature as the independent variable has good biological significance.The coefficients of determination of the equation are 0.9962-0.9988 and 0.9887-0.9922, respectively. Using the second-year data for model verification, the correlation coefficients of the simulated and measured values were 0.9933-0.9959 and 0.9830-0.9923, and the standardized root mean square errors were 6.64%-16.86% and 7.31%-12.68%, respectively. The prediction effect was good. Level. (3) The growth rate of dry matter and nitrogen accumulation of summer maize at different nitrogen supply levels all showed a "single peak curve", and its change was closely related to the nitrogen supply level. The performance between treatments was: under the condition of moderate fertilization, the growth rate curve It has the characteristics of fast rising and falling, and the growth rate curve of weight loss treatment has the characteristics of slow rising and falling.(4) The effective accumulated temperature ranges of dry matter and nitrogen accumulation during the rapid increase period of summer corn after sowing are 709.35-1 722.54 °C·d and 482.50-1 507.61 °C·d, and the effective accumulated temperature required for the maximum rate shows that nitrogen accumulation (995.05°C·d) is less than Dry matter accumulation (1 215.94 ℃·d). Nitrogen supply level obviously affects the accumulation of dry matter and nitrogen in summer maize to enter the accumulation temperature required for the rapid increase period, the accumulated temperature required for the slow increase period, the accumulated temperature required for the maximum increase rate, the maximum increase rate, and the average increase rate during the rapid increase period; Compared with nitrogen fertilizer treatment, the effective accumulated temperature required for summer corn to enter each critical period was significantly reduced, and the growth rate during the critical period increased significantly.【Conclusion】The normalized Gompertz model can not only simulate and predict the dynamic changes of summer maize dry matter and nitrogen accumulation with effective accumulated temperature with different nitrogen supply levels, but also clarify the quantitative relationship between effective accumulated temperature and dry matter and nitrogen accumulation. The Gompertz model based on effective accumulated temperature can be used to predict crop growth and optimal fertilization period, and has strong application value.

Key words: effective accumulated temperature, nitrogen supply level, summer maize, dry matter accumulation, nitrogen accumulation, quantification