The 2017-2018 wheat growing season is setting up similar to last year with many producers wanting to target more of the forage side of wheat production given the low commodity prices. That, coupled with the available soil moisture from the rainfall throughout August, has prompted some producers to get the drills rolling already over the past week in some parts of the state. As planting gets going, here are a couple considerations when it comes to planting dates and seeding rates for winter wheat in Oklahoma.
The optimal window for dual-purpose wheat for most of Oklahoma is between September 10-20 (approximately day 260 in Figure 1). This window represents a trade-off between maximizing forage production while minimizing potential grain yield loss. Earlier planting dates, last week into this week for example, will provide more fall forage potential, but this is usually not recommended unless the wheat is intended to be produced for grazing, or “grazeout.” Planting dates for grain-only producers will be at least 2-3 weeks later than what is the ideal dual-purpose planting date for your area. For many areas in Oklahoma, this will be around mid-October (approximately day 285 in Figure 1).
Figure 1. Forage and grain yield potential in relation to the day of the year. Every 1,000 kg/ha is equal to approximately 900 lb/acre or 15 bu/acre. Ideal planting dates for dual-purpose wheat in Oklahoma are mid-September (i.e., approximately day 260). Planting for grain-only should occur at least 2-3 weeks after dual-purpose planting (i.e., mid-October or approximately day 285).
Producers in forage-only or dual-purpose management should plant 1.5-2x the amount of seed that is recommended for grain-only production. For example, data collected in north-central Oklahoma has showed that increasing the seeding rate from 60 to 120 lb/acre can increase fall forage potential by as much as 500 lb/acre for a mid-September planting date (September 11 in Figure 2). The increase in forage potential by using this higher seeding rate can justify the cost of the extra seed. OSU recommends 120 lb seed/acre for most areas of Oklahoma, including irrigated fields in the Panhandle. Seeding rates for dryland fields in the Panhandle for this type of management can be lowered to 90 lb/acre. OSU recommends a 60 lb/acre seeding rate for grain-only production when planted during that optimal mid-October time. Dryland fields in the Panhandle can have their seeding rate lowered to 45 lb/acre. If planting happens to get delayed in November this year, seeding rates will need to increase to provide enough available tillers to still maintain maximum grain yield potential.
Figure 2. Fall forage yield collected in north-central Oklahoma as affected by seeding rate and planting date. Source: PSS-2178.
More information about dual-purpose wheat management can be found in the fact sheet PSS-2178 Dual-purpose Wheat: Management for Forage and Grain Production.