Fertility Seeding Rate
Seeding rates for dual-purpose wheat should be at least 1.5 times greater than those used for grain-only production. Many producers opt for seeding rates as high as 120 pounds per acre, and seeding rates as great as 180 pounds per acre can be beneficial to fall forage production (Figure 6.4). Higher seeding rates must be combined with narrower row spacing (eight inches or less). This combination reduces the amount of time required for the wheat canopy to close, which, in turn increases the amount of sunlight intercepted by the crop and daily forage production. Therefore, increased seeding rates and narrow row spacing are of even greater importance when planting is delayed and less time is available for forage production.
Dual-purpose wheat generally requires more fertilizer than grain-only production. It takes approximately 30 pounds per acre of nitrogen to produce 1000 pounds per acre of wheat forage. While some of this nitrogen is returned to the system via urine and manure, it is not evenly distributed and has minimal effect on subsequent grain yield. Nitrogen removed from the production system via grazing should either be accounted for by additional pre-plant nitrogen application or by top-dress applications in the spring.
Figure 6.5 The plant on the left received an in-furrow application of phosphorus and had faster emergence, increased early-season root growth, increased tillering, and more forage growth than the plant on the right.
Low soil pH has a greater influence on wheat forage production than grain yield. One of the primary impacts of low soil pH is reduced phosphorus availability. The wheat plant has a much shorter period of time available for root growth and interception and uptake of plant nutrients for forage production than it does for grain yield (Figure 6.5). To overcome this limitation, 20 to 40 pounds per acre of phosphorus fertilizer should be placed in-furrow at planting. In-furrow application of P fertilizer is more efficient than broadcast application. In fact, when used in combination with an acid-tolerant wheat variety, in-furrow application of P fertilizer can be used as a “short-term” alternative to lime application on rented or marginal soils.