Phyllochron Interval and Yield Response to Starter Fertilizer and Planting Date in Wheat.

An understanding of early leaf and tiller growth in wheat (Triticum Aestivum L.) and how it impacts yield is an important concept for properly managing winter wheat in North Carolina. Field trials were conducted at four locations in North Carolina in 2012-13 and 2103-14 to investigate the effects of planting date and starter fertilizer on phyllochron interval (PI) and yield. Planting date caused a response in PI and yield at each planting date. At each location, the later planting date resulted in a shorter PI. However, the earlier date planting resulted in the highest yields in 2013-14, while the later planting date resulted in the highest yields in 2012-13. Higher yields at the second planting date in 2012-13 were due to the fact that the shorter PI coupled with rapid growing degree day (GDD) accumulation resulted in early leaf and tiller development. Despite the shorter PI at the later planting in 2013-14, GDD were not accumulated as rapidly as in the previous year due to a colder winter and the plant could not compensate for the later planting. A yield response to starter fertilizer was only observed at two locations, and was largely due to nutrient leaching at the locations where the yield response was observed. Therefore, the results of this study indicate that choosing the proper planting date based on fall and winter weather conditions is one of the most influential decisions for yield. A starter fertilizer may be necessary if there is a potential for nutrient leaching.