Planting depth within-field soil variability effects on corn stand establishment and yield

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Seedbed conditions during corn (Zea Mays L.) planting can have substantial impact on corn stand establishment and final yield. Optimal stand establishment is associated with maintaining yield potential with sustained seedling vigor. Planting management decisions are complex due to spatial variability within-fields from changing soil characteristics, such as soil texture or landscape position. Furthermore, seedbed suitability varies temporally, and management decisions should also consider forecasted conditions. Field experiments conducted in central Missouri from 2017-2019 assessed varying corn planting depths on stand establishment and yield on fine- and coarse textured soils of an alluvial soil, and over summit, back-slope, and foot-slope slope positions of an alfisol claypan soil landscape. Additionally, in 2019, planting depths were conducted over two planting dates on a separate study of a claypan soil. On alluvial soil, deep planting (7.6 cm) often had the most uniform and timely emergence. Shallow planting (3.8 cm) had the least uniform emergence and was particularly troublesome on fine-textured soil under warm conditions. Total plot yield was not altered by changing planting depth, but individual plant performance revealed trends based on growing season, soil texture, and planting depth. On the claypan landscape investigation, stand establishment showed contrasting trends impacted by warm and cool growing conditions during the emergence period. When warm, deep planting depths provided enhanced emergence uniformity and rate, while the opposite was true for cool conditions. Planting depth influenced stand establishment characteristics, but only with cooler germination conditions. The back-slope position stand establishment changed the greatest across growing seasons and planting depths. In 2019, shallow (3.8 cm) and deep (7.6 cm) planting depths negatively impacted yield. Also, during the final year (2019), the early planting date experienced cool soil temperatures resulting in decreased emergence rate, uniformity, and percent. Corn yield was not affected by planting date or depth. These results indicate that certain soil textures and landscape positions require greater attention to achieve optimum stand establishment, and as such could be built into on-the-go planter prescriptions. These results also demonstrate that despite early establishment differences, corn can often compensate for performance issues and maintain similar yield potential.