When it comes to getting winter wheat stands established and in the best position to overwinter, University of Wisconsin cropping specialists offer up several best practices.
1. Variety Selection
As with any crop, variety selection is the most important factor to consider in maximizing winter wheat yield and profitability. When choosing a winter wheat variety, several factors must be considered. These include winter survival, insect and disease resistance, heading date, lodging, test weight and, most importantly, yield.
"Since no variety is ideal for every location, it's important to understand the crop environment and pest complex that affects your specific region to maximize yield," says Shawn Conley, soybean and small grains specialist. "Yield is based on the genetic potential and environmental conditions in which the crop is grown.
"By diversifying the genetic pool that is planted, a grower can hedge against crop failure. Select those varieties that perform well not only in your area but across experimental sites and years. This will increase the likelihood that, given next year’s environment — which you cannot control — the variety you selected will perform well."
Test weight is also an important factor to consider when selecting a variety, Conley says. The minimum test weight to be considered — a U.S. #2 soft red winter wheat — is 58 pounds per bushel. Wheat at lower test weights will be discounted.
"Both environment and pests may greatly affect test weight; therefore,
selecting a variety that has a high test-weight potential in your region is critical to maximizing economic gain," Conley adds. "Select a variety that has the specific insect- and disease-resistance characteristics that fit your needs.
"By selecting varieties with the appropriate level of resistance, crop yield loss may be either reduced or avoided without the need of pesticides. Careful management of resistant cultivars through crop and variety rotation are required to ensure that these characteristics are not lost."
Conley adds that crop height and lodging potential are also important varietal characteristics that may be affected by your cropping system. If the wheat crop is intended for grain only, it may be important to select a variety that is short in stature and has a low potential for lodging.
"This may decrease yield loss due to crop spoilage and harvest loss, as well as increase harvesting rate," he says. "However, if the wheat crop is to be used as silage or is to be harvested as both grain and straw, then selecting a taller variety may be warranted."
2. Plant New Seed in 2010
To maximize wheat yields in 2010, it's imperative that growers plant certified or private seed that is true to variety, clean and has a high germination percentage of better than 85%.
One reason to avoid planting bin-run seed is Fusarium Head Blight, or scab. Plant pathologist Paul Esker says scab incidence and severity was not as severe in last year's crop as it was in the prior year's crop; however, the presence of scab at low levels was noted at all of his variety trial locations in 2010.
Also, the incidence and severity of FHB was very high in several other soft red winter wheat-production states, areas where seed may be packed and shipped.
He says kernels from heads infected with scab may be shriveled or shrunken and lightweight. Some kernels may have a pink to red discoloration. Others may be bleached or white in color.
"The other reason to plant new seed in 2010 is related to the sprouting issues and low test weights growers experienced this year, both of which can negatively impact germination, tillering and overwintering," Esker says. "If growers absolutely need to plant saved seed due to availability or other economic considerations, the following steps should be taken to increase the likelihood of establishing a legal and good wheat crop."
Step One: Determine if you can legally plant the wheat seed you saved. , many private wheat varieties now come with statements, which buyers sign at the time of purchase, stating that they understand they are not authorized to use the harvested grain for seed. Most currently used public winter-wheat varieties are Plant Variety Protected (PVP). Though you may replant them on your own land, you do not have the right to trade or sell seed of those varieties to others for planting.
Step Two: Once you have determined if you can legally plant the seed you saved, the next step is to clean the wheat seed. It's important that wheat seed be cleaned to remove small and damaged seeds and to eliminate weed seeds.
"Removing small and damaged seeds will not only aid in crop establishment, but will also provide a more uniform wheat seedling stand," Esker says. "Removing small and damaged seeds will also increase the thousand-kernel weight (TKW), which serves as a measure of seed quality. Wheat seed with TKW values greater than 30 grams tend to have increased fall tiller number and seedling vigor.
Step Three: Perform a germination test. Germination tests can either be completed at home or by sending a sample to the Wisconsin Improvement Association.
A home test can be performed by counting out 4 sets of 100 seeds and placing each of them in a damp paper towel. Place the paper towel into a plastic bag to conserve moisture and store in a warm location out of direct sunlight.
After 5 days, count the number of germinated seeds that have both an intact root and shoot. This will give the grower an estimate of percentage of germination. It's important to choose random seeds throughout the entire seed lot and conduct at least four- to 100-seed counts.
"If germination is below 85%, it's important to increase the seeding rate to compensate," Esker says. "However, we would caution growers from seeding any wheat with a germination test below 80%."
Step Four: Assess the need for a seed treatment. A number of fungicides and insecticides are labeled for use as seed treatments on winter wheat. Seed treatment fungicides protect germinating seed and young seedlings from seedborne and soilborne pathogens.
"Seed treatment fungicides will not improve germination of seed that has been injured by environmental factors and will not resurrect dead seed," Esker says. "Remember, seed treatment fungicides applied this fall will not protect against potential scab infection next summer. If seed with scab must be used for planting, a seed treatment fungicide is a must."
3. Seeding Depth
Wheat should be planted about 1 inch deep depending upon soil moisture conditions, Conley says.
Wheat planted less than 0.5 inches deep may result in uneven germination due to seed exposure or dry soil conditions. Shallow-planted wheat is also more susceptible to soil heaving.
Wheat planted more than 1.5 inches deep may result in death due to premature leaf opening or poor tiller development and winter survival. Uniform seed placement and seeding depth are important in promoting crop health in the fall.
4. Crop Rotation
Yield data from Wisconsin's long-term rotation experiment located at Arlington, Wis., indicates that wheat grain yield was greatest when following soybeans, says John Gaska, outreach specialist.
Yield of second-year wheat was similar to wheat yields following corn for grain or silage. Third-, fourth- and fifth-year continuous wheat yields were dramatically lower than other rotational systems.
"Our data suggests that growers should plant wheat after soybean first, then corn silage, corn for grain and lastly wheat," Gaska says. "If growers choose to plant second-year wheat, several management factors should be considered to reduce risk."
First, Gaska says plant a different wheat variety in the second year that possesses excellent resistance to residue-borne diseases. Under no circumstances should growers consider planting bin-run seed in second-year wheat.
"By planting a different variety with strong disease resistance characteristics, you can reduce the likelihood of early disease pressure and significant yield loss," he says. "Growers should use a seed treatment in wheat following wheat. Be aware that seed treatments are not a cure-all for all common diseases in continuous wheat systems.
"Growers should also consider increasing their seeding rate to 1.8 to 2.0 million seeds per acre in wheat following wheat systems. This will aid in stand establishment and increase the likelihood of a uniform stand going into the winter.
"Lastly, if using a no-till system, planting into a seedbed that is free of living volunteer wheat is important in reducing the incidence of barley yellow dwarf virus. Growers should consider a herbicide application to any living volunteer wheat prior to planting to prevent a 'green bridge' for the aphids that vector this virus."
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