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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. |
