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Managing Wheat For Forage And Grain - Dual-Purpose System

Aug 14, 2017

By Romulo Lollato, Wheat and Forages Specialist

Dual-purpose wheat management (wheat grown for forage and grain) spreads production risks by providing producers a second source of income in addition to the harvested grain. If wheat grazing is managed properly, its grain yield penalty can be minimized.

If cattle are removed prior to first hollow stem, the probability of grain yield reduction due to grazing decreases and in many cases no yield penalty occurs, depending on growing season weather. Still, research has demonstrated that grazing wheat during late fall, winter, and early spring reduces grain yields on average by 7% compared to wheat managed for grain only. If cattle are not removed prior to first hollow stem, greater grain yield reductions can occur. In years when early spring conditions are not favorable – such as when there is a spring freeze after some varieties have begun jointing or when the spring turns out dry – wheat that has been grazed may even outyield ungrazed wheat. That’s because moderate to heavy grazing will typically delay maturity a bit in the spring and reduce some of the lush fall growth of early-planted wheat.

Overall, wheat pasture can provide high-quality forage when other forage sources are typically low in quality and quantity, and its management requires a few distinct considerations:

Seeding date. Early-planting is essential to ensure good fall forage production as long as soil moisture and temperature allows. Wheat grown under dual-purpose management is usually sown in September, at least two to three weeks earlier than wheat sown for grain-only. Research performed in north-central Oklahoma indicates that wheat fall forage production decreases approximately 1000 pounds per acre for each two-week delay in planting in September.

Seeding rate. Dual-purpose wheat management requires seeding rates 1.5 to 2.0 times greater than that for grain-only management. Research has shown that the increase in fall forage yield associated with increasing seeding rate from 90 to 120 lbs / acre pays for the increased seed cost in regions with approximately 30 inches annual precipitation or more, especially when planting is done early- to mid-September.

Seeding depth. Earlier planting date results in wheat planted into hotter soils. Increased soil temperature decreases the coleoptile length of germinating wheat, which can affect emergence of deep-planted seeds. Therefore, if moisture is not available in the top inch or inch-and-a-half of the soil profile, it is preferable to seed shallower and hope for rain (“dust the wheat in”) than to try to reach moisture deeper in the profile.

Variety selection. Wheat varieties grown under dual-purpose management should germinate well under high soil temperatures (> 85°F), should have excellent forage production and grazing potential in the fall, and recover well from grazing. Genetic resistance to barley yellow dwarf, wheat streak mosaic, and Hessian fly are also valuable traits as early planted wheat is at greater risk of damage by these diseases and pests. For more information on the first hollow stem and fall forage yield of different wheat varieties in Kansas, please click here. For information regarding variety-specific resistance to pests and diseases, please click here.

Nitrogen fertility. A bushel of wheat with 12.5% protein requires approximately 2 to 2.4 lbs N / acre during the growing season to be produced, regardless if management is for grain-only or dual-purpose.
Additionally, approximately 30 pounds of nitrogen per acre are needed to produce 1000 pounds of wheat forage in the fall/winter in dual-purpose systems. Thus, nitrogen requirements of dual-purpose wheat are generally 60 to 90 lbs N / acre greater than that of grain-only wheat. Nitrogen removed by grazing should be accounted for by additional pre-plant nitrogen fertilizer or by a topdress application during spring to ensure proper grain formation.

Starter P fertilizer. Wheat forage yield responds remarkably well to phosphorus (P) application because of improved tillering and the typical jump-start resulting from banded P. Phosphorus deficiency reduces tillering and makes plants more susceptible to winter­kill. Banded P applications at 50 to 60 pounds per acre diammonium phosphate (DAP) or the equivalent in P from other fertilizer sources at planting is more efficient than broadcasting, especially on acid soils low in available P.

Soil pH. Acidic soils are an especially important issue when growing wheat for forage and grain. Wheat forage production is more impacted by low soil pH than wheat grain yield, and extremely acidic soils can decrease forage production even in low pH tolerant varieties (Figure 1). A minimum soil pH of approximately 6 is needed to maximize wheat fall forage production for most wheat varieties. In-furrow phosphorus fertilizer can be used as a strategy to ameliorate the effects of low soil pH and increase wheat forage production in acidic soils.

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