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From the Field
By Brad Meyer, Edited by Dr. Dewey Lee

Wheat Management

Throughout the state, many of our fields are green this winter. Though the official count on wheat acres has yet to be published, common sense and commodity price tells me more wheat acres have been planted in Alabama this year than we have seen since the 1980s. With the rise of prices and the yield potential present in many counties in the state, wheat has found its way into the role of primary crop and we should now manage it accordingly. Many of the management practices in wheat that maximize yields are similar to those Alabama growers practice in other crops. The only hurdle is to decide to use them.

According to Dewey Lee, Extension Agronomist at the University of Georgia, "New techniques developed in the Southeast United States over the last decade in soft red winter wheat production have increased yields on farms considerably. Research started in the early 1980s shows yields of soft red winter wheat can reach over 100 bushels per acre with the right environment."

As with all things worthwhile, achieving higher wheat yield demands effort. Though intensive wheat management will require some time this spring, high wheat prices will make the reward well worth the effort and the intensive management should be familiar to growers in Alabama.

Nitrogen Management

High wheat yields depend on properly managing nitrogen applications in the late winter and early spring.

"Nitrogen management is a key factor in high-yield wheat management. Nitrogen fertilizer is the most expensive variable cost in wheat production. It is critical this input be managed for maximum return on this investment." To do this, Dr. Lee stresses "the key is to provide the essential amount of nitrogen at critical growth stages for most efficient use."

Total nitrogen use depends on yield goals.

"For expected yields of 40 to 70 bushels per acre, use a total (including fall applications) of 80 to 100 lbs. N/acre. Results from Georgia and Alabama indicate for most soils application of 120 lbs. N/acre is necessary for yield goals of 70 to 100 bushels/a."

Timing of nitrogen applications in the late winter and early spring depends on wheat’s uptake pattern and the condition of the crop.

"For high yields it is desirable to obtain 50 to 70 heads per square foot. To achieve this, there has to be enough nitrogen for wheat to develop 80 to 100 tillers per square foot prior to stem elongation." Scout wheat fields in late winter and count tillers. "If the tiller count is less than 80 per square foot, then apply 30 to 40 lbs. of N per acre" prior to spring green up. This will encourage tiller production. Apply the balance of nitrogen just prior to stem elongation. "If tiller counts exceed 80 or more per square foot, then apply all remaining nitrogen just prior to stem elongation." Rapid nitrogen uptake begins with stem elongation.

Disease Management

Disease management in wheat normally begins with variety selection. Choosing a variety based on disease resistance was difficult this year because supply of planting seed was cut short by the late freeze last spring in many of the production areas and demand for seed surged throughout the fall. As we go into the spring, it will be very important to know the characteristics of the varieties planted and manage for disease pressure accordingly. Fungicides can be a very effective tool for protecting yield, but they should only be used after careful consideration of factors such as field history, disease incidence and severity, type of disease, yield potential, moisture conditions and temperature. In short, only make a fungicide application when it will make money.

Scout wheat fields for disease beginning at stem elongation. Leaf rust, stripe rust, leaf blotch, glume blotch and powdery mildew are common diseases in Alabama that can be controlled with fungicides. Fungicides will provide the maximum benefit when a controllable disease is present, yield potential is high, a susceptible variety is planted, wheat canopy is dense and conditions are conducive for the spread of the disease. Generally, the most effective time to apply fungicides is from flag leaf emergence to early heading. It is important to protect the flag leaf because it provides a large portion of the leaf area contributing to grain fill. Barley yellow dwarf virus is a common disease spread by aphids. Severity of this disease can be reduced by controlling aphids.

Insect/Weed Management

Insect control in wheat is similar to pest management in other crops. It requires scouting, identifying pests and applying control measures if insect pest levels surpass economic thresholds. Spring scouting for insects should begin as tiller counts are made in late winter. Aphids will be the first insect present in wheat fields and will normally be the main pest. Many species of aphids attack wheat, damaging plants directly through feeding and indirectly by vectoring barley yellow dwarf virus. Cereal leaf beetles need to be scouted for beginning in mid-March. Typically in Alabama, the larva of the cereal leaf beetle feeds on wheat leaves from the boot stage to early heading. Also, watch for true armyworms while scouting in the spring during stem elongation and heading.

"A good weed control program is essential to produce profitable high wheat yields. Weeds reduce yields by competing for nutrients, sunlight and moisture. They also reduce your profits by contaminating grain with seed which results in dockage and a reduction in price at the elevator." To control weeds with herbicides most effectively, apply when weeds are small. Fields need to be scouted for weeds as tiller counts are made in late winter. Common winter weeds in Alabama are Italian ryegrass, poa annua, henbit, wild garlic, wild mustard and chickweed. To insure crop safety and maximize effectiveness, applications of most herbicides need to be made after tillers have fully formed and before stem elongation.

Author’s Note: Dr. Dewey Lee is a professor and Extension Agronomist with the University of Georgia. He graciously allowed me to reference his information on intensive wheat management and agreed to edit this article. Quotes are from "Intensive Wheat Management in Georgia" and "Critical Management Inputs for High Yield Wheat Production" by Dr. Lee. Information on intensive wheat management can be found at: http://pubs.caes.uga.edu/caespubs/pubcd/B1135.htm.

Brad Meyers is an agronomist for Agri-AFC. Contact him at [email protected].


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Date Last Updated January, 2006