Impact of Corn Planting Date on Yield, Growth, and Management.

Field trials were conducted at three locations in eastern Arkansas during 2008-2011 growing season evaluating the impact of corn planting date on yield and crop development.  Locations included Rohwer, in southeast Arkansas, Marianna in east-central Arkansas, and Keiser in Northeast Arkansas.  In each year eight commercially available adapted hybrids with relative maturity of 110 to 120 days were planted from March until late May or June to evaluate impacts of planting dates.  In each planting date at least one non-bt hybrid was included to evaluate planting date impact on yield loss caused by corn borer.    All plots were fully irrigated by pivot or furrow irrigation.  Row spacing at each location was 38 inches, which is typical for much of eastern Arkansas.  At harvest plots were harvested with a small plot combine and yields were adjusted for moisture content.  Yields varied year by year due to weather conditions, but yields were generally greatest from March to Mid-April plantings in most years.  Although when heavy rains and saturated soil conditions persisted in early plantings, yields from later plantings were better in some instances, indicating corn yield is correlated to early season growing conditions.  Yields of non-bt hybrids were similar to those of bt hybrids when planted in March through Mid-April.  After mid-April, at sites where corn borer was present, corn yields tended to decrease more rapidly compared to their bt version.