Impact of Corn Planting Date On Growth and Yield.

Corn is planted early in the Mid-south for a variety of reasons, including perceived greater yield compared to later plantings, less insect and foliar disease pressure, and early harvest. Current optimum planting date for Arkansas corn varies south to north, but Mid-March to Mid-April is considered optimum. However in many years, rainfall and wet soil conditions dictate when corn is planted. In recent years, flooding and a late freeze have caused many acres of corn to be replanted or initial plantings were delayed later than desired. Planting date studies were conducted from 2008-2011 on furrow irrigated corn in the Mississippi river Delta region of Eastern Arkansas. Yields from these trials indicate that with adapted hybrids, irrigation, Bt technology, and proper management, maximum corn yields can be maintained until Mid-May in most years. Yields of corn planted after mid-May declined approximately one percent per day. Corn planted in Mid-April or later had increased probability of needing foliar fungicide to control southern rust, which generally develops later in the growing season. Risks associated with hurricanes, which can cause tremendous losses because of plant lodging, increase with later plantings. Corn planted in March or early April generally took 140 to 150 days from planting to reach grain moistures of 15 percent or less. When corn was planted in late April through May, plants developed much quicker because of increase accumulations of heat units and it only took 120 to 130 days for grain moisture to reach 15 percent or less. Planting corn in May can produce excellent yields, but producers should consider risks of late planting.