Planting date influence on dual-purpose winter wheat forage yield, grain yield, and test weight

The use of winter wheat (Triticum aestivum L.) as a dual-purpose forage and grain crop is important to the agricultural economies of the Southern Great Plains of the USA. Planting date is an important management factor in determining the economic success of a dual-purpose winter wheat enterprise. The overall objective of the research reported in this paper is to determine the economic optimal planting date for dual-purpose winter wheat production. The specific objectives are to determine wheat fall-winter forage yield, wheat grain yield, and wheat test weight response to planting date for dual-purpose winter wheat production. Field studies were conducted in north central Oklahoma from 1991-1992 through 1999-2000. The impact of alternative planting dates on dual-purpose wheat fall-winter forage yield, grain yield, and test weight was estimated. Estimated response functions illustrate that delaying the planting date from 10 to 30 September resulted in an 18% increase in expected grain yield, a 68% decrease in expected fall-winter forage yield, and only a 0.5% increase in expected test weight. Optimal planting date is sensitive to the relative value of wheat fall-winter forage and wheat grain, but not sensitive to wheat test weight discount schedules. When the value of wheat forage is high relative to the value of grain, it is more profitable to plant early to increase expected forage yield. Alternatively, when the value of grain is high relative to the value of forage, later planting generates greater net returns.