Observations from the Kentucky Corn Yield Contest reveal mid‐ to late‐season weather, early planting, and planting population drive high corn yield

Vollständiger Abstract

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Abstract Corn ( Zea mays L.) is the most valuable row crop on a land area basis in Kentucky. Understanding the effects of management practices employed by farmers in high‐yielding corn fields in Kentucky is essential for identifying both challenges and opportunities in corn production. In this study, we evaluated how farmers management strategies influenced yield using data from the Kentucky Corn Yield Contest, which typically represent the highest‐yielding fields in the state. Among individual management practices, planting population emerged as the most influential factor. Growers who targeted 36,000–37,000 plants ac −1 achieved an average yield of 292 bu ac −1 (14 bu ac −1 higher than those who planted 34,000), whereas populations exceeding 37,000 were not associated with addition yield increases. However, when meteorological conditions were analyzed alongside management practices, weather patterns—particularly those in August—were the primary factors associated with yield variation. The highest yields occurred in years when August was not excessively dry and July provided both adequate solar radiation and periodic rainfall. Conversely, when August conditions were dry, earlier planting in April was associated with higher yields, potentially because critical growth stages occurred before late‐season moisture stress. In seasons when April rainfall was high, likely delaying planting into May, growers achieved greater yields by targeting harvest populations of ≥33,500 plants ac −1 . Together, these results suggest that high corn yields in Kentucky reflected the interaction of planting population with mid‐ to late‐season weather, particularly solar radiation and precipitation during July and August.