The When and Why of Barren Plants in High Yield Corn.

Barren corn plants are unwelcome in grain corn production systems because they are perceived as reducing overall yields per unit area.  The traditional thinking is that barren plants in corn fields are primarily the result of late emergence or poor plant spacing.  Competition for light energy is the most common stress factor identified in the development of barren plants, but other competition factors may also operate.  Intense season-long investigations of tagged plants over the past several years in high yield corn systems have revealed that barren plants at maturity are not primarily due to delayed emergence or poor plant spacing.  Instead, barren plants are part of the group of “dominated” plants that gradually fall behind their neighbors during late vegetative, flowering, and early reproduction stages.  Barren plants are proportionately more likely to occur at high plant densities, when nutrients are limited, or when other stresses are experienced during the season.  A major aspect of achieving corn yield improvement at high plant densities in the future will lie in understanding the management factors other than seed depth or seed spacing that are important to achieving greater uniformity in intra-specific plant development and per-plant kernel weights during the whole growing season.