The optimal planting window for winter wheat in western Kentucky is quickly approaching: October 10-30. Prior to the physical planting of wheat, farmers must make several critical decisions to maximize wheat grain yield and profitability the following June. The first is variety selection.
In Kentucky there is an annual risk of Fusarium Head Blight (caused by Fusarium graminearum) infection of wheat. This disease not only reduces yield, but it also produces a toxin in the grain (vomitoxin or deoxynivalenol) which can result in considerable price reduction when delivered to the grain elevator. The best way to reduce the risk of Fusarium Head Blight is to grow a moderately resistant cultivar. If the seed representative you are buying your seed from does not know how resistant a cultivar is to Fusarium Head Blight, it is best to choose another cultivar with known resistance.
Seed depth and seeding rate are also very important. The optimal planting depth for wheat seed is 1 to 1.5 inches with good seed-to-soil contact. These depths help reduce the risk of winter injury and heaving. Heaving occurs during periods that soil freezes and thaws. During these freeze/thaw cycles the wheat seed can be pushed closer to the soil surface causing plant injury and possibly death, which can ultimately reduce plant stands and grain yield. When soil conditions are extremely dry at planting, wheat seed can be planted up to 2 inches deep to access soil moisture. Do not plant wheat seed greater than 2 inches.
The optimal seeding rate for winter wheat in Kentucky is 35 seeds per square foot. Some farmers prefer to use pounds of seed per acre. When using pounds per acre, seed size is critical. Wheat seed size varies considerably and be determined by counting the number of seed per pound (usually on seed tag). Seeding rates based upon weight alone can result in plant populations that are too high or too low, depending on seed size. Seeding rates that are too high result in high plant populations that are prone to lodging (falling over in the field) and have lower grain yield. Seeding rates that are too low may result in low plant populations and reduced yields. Additionally, seed germination must be considered. This can be accomplished by dividing your desired plant population by the germination rate of your seed: 35 seed per square foot Ã Â· 0.92 (92 percent germination rate) = 38 seed per square foot.
Many winter wheat fields are no-till production systems, where the residue from the previous crop remains on the soil surface at the time of wheat planting. In Kentucky, most winter wheat follows corn. Proper seeding depth and rate is especially important and challenging in no-till production systems. Ensuring that residue from the previous crop is uniformly distributed throughout the field will help with uniform wheat planting and emergence, which is necessary for high wheat yields the following summer.
The final consideration for this season's winter wheat planting is fall fertility. In most years fall nitrogen applications are not necessary for wheat. However, this year we have had considerable rainfall and even flooding of fields that do not typically flood. These conditions likely depleted much of the nitrogen that would usually be available to the wheat crop in the fall. If you are in an area that received excessive rainfall or your fields were flooded at least once this season for several days or longer, you may want to consider a fall nitrogen application of about 20 to 30 pounds N per acre. Do not exceed 40 pounds per acre.
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