Response of Lodging Resistance and Grain Yield to EDAH and Different Fertilization Combinations in Maize (Zea mays L.).

Stalk lodging is one of the major constraints limiting global maize yield. Chemical regulation and fertilization are essential agronomic practices that play critical roles in improving maize yield and lodging resistance. This study aimed to investigate the effects of different fertilization methods on maize plant morphology, stem mechanical properties and chemical composition, and yield under spraying chemical regulator (EDAH, consist of 27% ethephon and 3% DA-6). The experiment was conducted from 2023 to 2025, using Jiangyu668 (JY668) and Jiangyu877 (JY877) with different plant heights. Three fertilization methods (no fertilization, N0; conventional fertilization, N15; and slow-release fertilization, SN15) were set up. Chemical regulation and fertilization methods had significant effects on plant morphology, stem mechanical properties and chemical composition, lodging rate, and grain yield. The combination of spraying EDAH and slow-release fertilization optimized ear position coefficient and gravity center, decreased stem-leaf angle, and increased leaf orientation value, which was beneficial for improving leaf photosynthetic capacity. EDAH and slow-release fertilization also increased the stem internode diameter and aerial root layers; enhanced bending resistance and puncture strength; and increased cellulose, hemicellulose, and lignin contents and the lodging resistance index. These changes synergistically increased grain number and weight, ultimately increased maize yield, and decreased the lodging rate. CSN15 had highest yield and lowest lodging rate in different years and varieties. SN15 increased yield by 10.58% compared with N15, and CSN15 increased yield by 10.53% compared with CN15. JY877, as a medium- to high-stem maize variety, had better performance in plant morphology and yield than JY668 (dwarf maize variety) under EDAH and slow-release fertilization. These findings demonstrate that the strategy of combining chemical regulation and slow-release fertilization represents an optimal management approach for enhancing grain yield by optimizing plant morphology and improving stem mechanical properties and stem chemical composition in maize production. This strategy can increase agricultural productivity by enhancing yield and lodging resistance and provide significant environmental benefits and a scientific basis for agronomic practice recommendations.