Irrigated cotton acreage is limited in North Carolina. Research was conducted in North Carolina from 2004 to 2007 to define interactions of planting date with either mepiquat chloride application or cultivar under sub-surface drip irrigation or no irrigation. In most instances planting date, cultivar or mepiquat chloride, and irrigation did not interact for seed cotton yield. While main effects of planting date and irrigation were often significant, mepiquat chloride did not affect cotton yield. Cotton response to irrigation and planting date was variable and was generally influenced by annual variability in rainfall. Results from these experiments suggest that sub-surface drip irrigation improves cotton yield stability over the planting dates, mepiquat chloride applications, and cultivars tested. Additionally, cotton response to planting date was independent of irrigation treatment.
