Study On Maize Densification Effect Based On APSIM Model

Increasing plant density is a common cultivation measure to increase yield in food production.Selecting the optimum density suitable for crop growth is an effective way to increase grain yield.The existing research on maize densification planting is still empirical and lacks efficient and intelligent research tools.The model tools was used to study the response characteristics of maize to different plant density,which was conducive to selecting the optimal density and assisting grain production.APSIM-Maize is an integrated system of crop growth model developed in Australia that simulates maize production according to climate,soil,crop types and cultivars,tillage methods and field managements.However,APSIM-Maize has not been used to simulate high-density planting,and its adaptability remains to be evaluated.In this study,Zhengdan 958 and Jinqiu 119 were selected as the main varieties in Huaibei Plain,and five planting densities were set as 45,000,60,000,75,000,90,000,and 120,000 plants/hm~2.Summer maize density experiment was carried out in 2021-2022 in Mengcheng of Anhui Province to explore the response characteristics of growth,development and grain yield of summer corn to different plant densities.And the determining crop genetic parameters related to plant density were explored.Field experiment data were used to test the ability of APSIM-Maize to simulate high-density,and relevant parameters of the model were modified to correct the model’s adaptability in maize dense planting.The prediction accuracy of APSIM-Maize was verified with independent data sets.The main results are as follows:(1)With the increase of plant density,the growth,development and grain yield of summer maize had varying degrees of response.The phenological parameters of APSIM-Maize model were relatively stable,with extinction coefficient(k)decreasing with increasing density and radiation use efficiency(RUE)increasing with increasing density.(2)The APSIM-Maize model simulated maize growth very well(NRMSE≤11.0%)at lower densities(45,000 plants/hm~2,60,000 plants/hm~2).However,the simulation effect of LAI,biomass and grain yield was poor(22.9%<NRMSE<40.2%)under high density(75,000 plants/hm~2,90,000 plants/hm~2,120,000 plants/hm~2).(3)Modified crop genetic parameters related to planting density,APISM-Maize can simulate LAI(NRMSE<25.0%)for 90000 plants/hm~2,phenological period(NRMSE<3.0%),above-ground biomass(NRMSE<28.0%)and yield(NRMSE≤3.0%)for all five densities.At the same time,the variation trends of LAI,biomass accumulation and grain yield with density can be simulated.In conclusion,the modified parameters of APSIM-Maize can be used to simulate the study of summer maize density increase of 45,000-90,000 plants/hm~2,and provide a reference for the extension application of APSIM-Maize in the Huabei Plain.