Winter wheat fall-winter forage yield and grain yield response to planting date in a dual-purpose system

Previous published research suggests that if fall-winter grazing of winter wheat is properly managed, it will not reduce grain yield. However, highly aggregated state average data suggest that fall-winter grazing is associated with lower grain yields. This study was undertaken to determine the trade-off, or substitution in production, between winter wheat fall-winter forage yield and grain yield across planting dates. Data from experiment station trials were used to estimate response functions and to determine optimal planting dates. The estimated response functions suggest relatively large differences in expected fall-winter forage yield and expected grain yield across planting date. Optimal planting date is sensitive to the value of fall-winter forage relative to the value of wheat grain. Producers will optimally plant wheat intended for dual-purpose use earlier than wheat intended for grain-only. The expected yield from the earlier planted dual-purpose wheat is lower than the expected yield of the later planted grain-only wheat as a result of the earlier planting date. (C) 2000 Elsevier Science Ltd. All rights reserved.