Understanding Wheat Head Count Effect on Yield

Older data from University of Kentucky suggests that a final head count of 60 to 70 per square foot (540 to 630 per square yard) is considered acceptable for excellent wheat yields in Kentucky (ID:125 Ch 3). The Yield Enhancement Network data identified that the top 20 yields in the network had head counts closer to 1041 heads per square yard and the bottom 20 yields had head counts closer to 661 (Dennis Pennington, personal communication), both of which are above current University of Kentucky expectations. While the YEN data likely skews north where higher wheat yields are more common, there is merit to evaluating head counts on wheat in Kentucky to determine if there is a new number to target for head counts. To help answer this question, this proposal will include two sets of studies: 1) small plots with replicated treatments and 2) farmer fields. The small plot trials will most likely occur at two locations (Spindletop Farm and Princeton UKREC) and include three varieties, four seed rates and two nitrogen rates to try to generate various head counts to evaluate. For the farmer fields, we will ask growers to plant strips of different seeding rates and then conduct head counts among those strips. Ideally, all of these studies and fields will be tilled following corn or no-till following soybean.