<b>Assessment of corn yield and physiological performance via fungicide placement and intensive management strategies</b>
Creators: name: Silva, Malena Bartaburu
Publisher: name: Purdue University Graduate School
Year: 2024
Subjects: classificationCode: 300403
subject: Agronomy

description: In response to fluctuating corn (<i>Zea mays</i> L.) prices, climatic variability, and emerging diseases, farmers are increasingly adopting diverse and intensive management practices to enhance yield and profitability. This research investigates the performance of various inputs and management practices on corn production across multiple site-years, with a focus on yield components, grain fill duration, kernel development, disease severity, and economic outcomes. A multi-state research trial was established to evaluate the impact of seven inputs and management practices across multiple locations and environments in Indiana, Kentucky, and Michigan in 2022 and 2023. Each location included eight treatments: 1) control treatment (C) based on Purdue University seed rate and nitrogen (N) fertilizer recommendations (Camberato et al., 2022; Nielsen et al., 2022): 30K seeds per acre and N fertilizer application as starter (2x2) and V5 growth stage sidedress. Total N rates ranged between 180 and 200 lbs N per acre and agronomic optimum nitrogen rates (AONR) were used, 2) C + banded (2x2) fungicide, 3) C + 20% increase in corn seeding rate, 4) C + sulfur (S) fertilizer, 5) C + foliar micronutrients, 6) C + late-season N fertilizer application (V10-12 growth stage), 7) C + R1 foliar fungicide, and 8) intensive treatment (all additional inputs/management practices applied). The intensive treatment significantly increased yield by 16.4 and 18.4 bu ac<sup>-1</sup> in 2022 and 2023, respectively when compared to the control across locations, but did not enhance net profit across multiple corn price scenarios due to high application costs. Conversely, R1 fungicide applications increased yield by 16.2 and 16.7 bu ac<sup>-1</sup> in 2022 and 2023, respectively, and S applications increased yield by 12.9 bu ac<sup>-1</sup> in 2023, when compared to the control, with both treatments improving net profit under multiple corn price scenarios. In addition, kernel development studies in West Lafayette, IN, during 2022 and 2023 revealed that banded fungicide applications at planting and foliar fungicide applications at the R1 growth stage can reduce leaf disease severity by 3.2% to 6.6%, extend grain fill duration by 3.5 to 4.5 days, and increase maximum dry kernel weight at plant maturity by 5.7 to 9.4%, respectively, leading to further insights into the yield response mechanisms. Furthermore, a meta-analysis of 24 at-plant flutriafol fungicide placement trials across Indiana (2020 – 2023) highlighted the effectiveness of at-plant fungicides, with banded (2x2 or 2x0) applications leading to the highest yield increase of 7.8 bu ac<sup>-1</sup> and both banded and in-furrow applications reducing disease severity on corn ear leaves at the R5 growth stage by 2.1 - 2.3% when compared to the control. These findings suggest both at-plant banded and R1 foliar fungicide applications have the potential to reduce disease severity, extend corn grain fill duration, and improve yield when conditions are conducive for a response (e.g., foliar disease presence). Overall, this research highlights the ability of targeted input applications for improving both corn yield and profitability when examined across diverse environments and locations, rather than prophylactic applications of multiple inputs and increased management intensities.