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

Seedbed conditions during corn (Zea mays L.) planting can have substantial impact on corn stand establishment and final yield. Planting management decisions are complex due to spatial variability caused by changing soil characteristics such as soil texture or landscape position. Field experiments conducted in central Missouri from 2017 to 2019 assessed the effects of varying corn planting depths on stand establishment and yield. Sites included fine- and coarse-textured alluvial soils, and summit, back, and foot slope positions of Alfisol claypan soil landscapes. 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. Under these conditions, grain yield for one site-year was 2.8 Mg ha(-1) less when planting shallow compared with planting deep. On the claypan landscape position study, stand establishment was affected by both warm and cool growing conditions during the emergence period. During warm conditions, deep planting enhanced emergence uniformity and rate (1.1 d less to reach 90% emergence than shallow planting); the opposite was true for cool conditions (3.7 d more). Yield was not affected by planting depth at any of the site-years of the landscape position study. These results indicate that certain soil textures and landscape positions require greater attention to planting depth to achieve optimum stand establishment. Differences could be used in on-the-go planter prescriptions. These findings also demonstrate that despite early establishment differences, stands can often compensate and maintain similar yield.