Published on Monday, September 26, 2016
Variety Selection. Select varieties that are best suited for your operation’s needs, whether that’s based on maturity for harvest timing and soybean double-cropping, straw and/or grain yield, management level, or a combination of these needs. In addition, maturity and harvest timing may be important for timely manure management, summer drainage tile projects, or timely cover-crop seeding. Utilize data from universities, third-party testing services, seed companies, and local performance-based product recommendations from your Beck’s representative to help select the best varieties available. University of Illinois research from 2013 and 2014 shows a 20 percent difference in grain yield just by selecting top-performing wheat varieties.
Soil Test. A soil test prior to planting will help determine the need to correct pH and the potential yield response of wheat to various fertilizer products. A complete soil analysis that includes the basic package, as well as micronutrients, % base saturations, and cation exchange capacity (CEC) is beneficial for identifying yield-limiting factors related to plant nutrition.
Fall Pre-Plant Fertilizer. The most common broadcast dry fertilizers in the fall prior to planting wheat are DAP (18-46-0), MAP (11-52-0), AMS (21-0-0-24S), MESZ (12-40-0-10S-1Zn), manure, or a combination of those products. Depending on the soil test results, wheat may respond significantly to these “starter” applications of fertilizer, especially ones containing phosphorus (P) when the value of P is below 60 lb./A. Application rates of fall fertilizer prior to planting wheat should be based on P needs first, followed by nitrogen (N). For example, applying 200 lb./A. of DAP would supply enough P for crop removal of 100 Bu./A. wheat, and would also supply 36 lb./A. of N. Nitrogen and P in the “starter” will help promote fall tillers and good root development prior to winter dormancy.
Common N rates applied in the fall often range from 27 to45 lb./A., however, recent Beck’s Practical Farm Research (PFR)® shows a positive return on investment (ROI) from adding 50 lb./A of N. For example, this could be accomplished by using additional urea or AMS with DAP. If planting is delayed, N rates up to 50 lb./A. in the fall may help stimulate tiller development and root growth, which can boost the plant’s ability to survive harsh weather conditions by storing more nutritional reserves. Sugars stored in the crown of the plant act as antifreeze to help with winterhardiness.
Tillage and Previous Crop. Light tillage with a vertical tillage tool or disk prior to planting may be helpful to incorporate broadcast fertilizer, create a uniform weed-free seedbed, and may be necessary if a large amount of residue is present from a previous crop that could prevent consistent, optimum seed-to-soil contact at the proper depth. Recent research from Beck’s PFR program shows vertical tillage prior to planting wheat has provided the highest ROI when compared to no-till and conventional till systems. Wheat planted after corn can suffer a carbon penalty effect, similar to corn residue in a corn after corn system. In addition, wheat is more susceptible to diseases when planted after corn. Be sure to plan proper disease management practices if planting wheat after corn.
Planting Date. Like most crops, the optimum planting date will vary from year to year, depending on environment and weather conditions. However, if soil conditions are right, planting wheat near or just after the Hessian fly-free date is preferred. When possible, wheat should be planted within the first 10 days of the fly-free date to allow good fall tiller development and obtain maximum yields. Planting prior to the fly-free date for your area is not preferred; however, the insecticide in Beck’s Escalate™ seed treatment would generally allow planting a few days prior to the fly-free date.
Seed Treatments. Use seed treatments to help protect genetic potential and maximize yield. Beck’s Escalate yield enhancement system comes standard on every bag of Beck’s wheat. Offering insect protection, improved stands, and higher yields, Escalate is a mixture of the industry’s top fungicides, insecticide, and biological growth promoters. Multi-year data from Beck’s PFR shows that the Escalate provides a 4 to7 Bu./A. yield advantage.
Seeding Rate and Depth. Although many wheat growers still plant according to lb./A. or bags/A., it is highly recommended that seeding rate be done by seeds/A. Wheat seed size can vary by variety and also production lot within a variety. Some may be as large as 10,000 seeds/lb., while others may be as small as 16,000 seeds/lb. When planting is NOT delayed by more than 10 days past the fly-free date, use the seeding rates below:
Tilled then drilled/planted – 1.4 million viable seeds/A.
No-till drilled/planted – 1.5 million viable seeds/A.
Spread with fertilizer and tilled – 1.7 million viable seeds/A.
Remember to take into account the percent germination on the seed tag. For example, if you are using seed with 90 percent germination and drilling into tilled soils within 10 days of the fly-free date, you need to plant 1,400,000/90% = 1,555,555 seeds/A. If seed size of the variety you are planting is 13,000 seeds/lb., you would need to plant 120 lb./A. If planting is delayed more than 10 days past the fly-free date, increase the above rates by 15 percent. A seeding depth of 1 to 1.5 in. is generally an acceptable range. Under dry soil conditions, seeding depths closer to 1.5 in. may lead to more consistent emergence and may also help reduce winter heaving compared to shallower-planted seed.
Assessing Winter Kill, Stand and Frost Injury. Prior to “green-up” in the spring, it’s important to evaluate the population and amount of heaving and/or winter kill. If planting was delayed in the fall, there is a greater potential for less tiller development, smaller root development, and more stand loss. For maximum yields, 30 to 35 healthy plants per square foot are required, not counting tillers. Good yields can come from fields with lower stand counts, however, if population is less than 15 plants per square foot, 25 percent or more of the yield potential has been lost. In 7.5 in. drilled wheat, measure 19.2 in. down a row. Then count the number of plants.
Do this in many spots throughout the field to get an average. For 10 in. row spacing, measure 14.4 in., and count the plants. When air temperatures fall significantly below 32°F, frost injury can occur on leaf tips, especially when there is little to no snow cover to serve as an insulation blanket. Leaf “tip burn” from frost injury usually has little to no effect on yield. If stands are adequate and there is very little to no tiller development in late February to early March, N should be applied as soon as possible to stimulate tillering. The N source should contain mostly ammonium and/or nitrate forms of N, such as AMS, AMN or UAN. Each plant should produce 2 to 3 tillers to maximize yield.
The wheat pictured on the left was planted 20 days after the fly-free date for the area. The plants have very few tillers and very little root development due to a lack of heat units since planting in mid to late January. Leaf tips are showing a “bleaching” effect from frost injury due to very cold temperatures (<20°F) with little snow cover.
Tissue Tests. The most practical time in the spring to tissue sample wheat is about a week prior to green-up (Feekes 4) and topdressing. This will allow time for sample results to be analyzed for nutrient deficiencies. Nutrients such as boron (B), zinc (Zn), sulfur (S) and others may need to be added to a topdress N application to maximize yield.
Spring Nitrogen Source, Rate and Timing. Proper N management in wheat is a major critical component for maximizing yields, ROI, standability, and nutrient stewardship. Choosing the correct N source and timing for late winter and/or early spring topdressing can be difficult because many product options may be available and field conditions may be less than desirable. Depending on your area and supplier, you may be able to choose from liquid products such as UAN (28-0-0 or 32-0-0), manure, or by-products containing N, S, and possibly other nutrients. Options for dry products may include urea (46-0-0), ESN (44-0-0), AMS (21-0-0-24S), AMN (34-0-0), or manure. It is important to remember that wheat can take up ammonium and nitrate forms of N. Other forms, like urea, must be converted to ammonium and nitrate before it can be utilized by the plants. If making N applications at or prior to green-up (Feekes 4) with optimal stands and tillering, using N sources that contain urea are acceptable. Warm, windy, and damp weather conditions favor ammonia volatilization. By using a urease inhibitor such as Agrotain with dry urea-based products, it will likely reduce N losses. If applying liquid UAN prior to green-up, using a nitrification inhibitor such as Instinct® will help keep N in the ammonium form, thereby reducing N losses from leaching and denitrification. Multi-location data from Beck’s 2015-2016 PFR showed that when Agrotain® Plus, which is a combination product containing a urease inhibitor and a nitrification inhibitor, is used with 120 lb./A. of N (40 g/A. of 28% UAN) in a spring topdress application, provided similar results to split topdress applications of UAN without Agrotain Plus supplying 50 lb./A. of N followed by 70 lb./A. In contrast, if using non-coated urea as your spring topdress N source, our data indicates an economic advantage of about $30/A. when split applying 50 lb./A. of N followed by 70 lb./A. of N compared to a single application of SuperU™ (urea treated with Agrotain Plus). In general, wheat should be topdressed no later than the jointing stage (Feekes 6). The longer a N topdress application is delayed, growers should avoid using urea-based N fertilizer sources because of the time necessary for urea conversion to ammonium and nitrate. Examples of products containing more than 50 percent of the N in the urea form are urea and ESN.
A limited amount of research in the Midwest has suggested that split N applications in the spring may lead to increased yield. These occurrences are very rare and not likely to occur if:
An adequate amount of N has been applied in the fall prior to planting.
A properly-timed spring topdress application has been made.
Weather conditions in the spring after topdress application have not favored N loss due to volatilization, leaching, and/or denitrification.
Lastly, how much total N should be applied? Let’s first remember that there is no N “credit” given toward wheat from a previous soybean crop. In addition, soil nitrates that may be present after corn harvest are also not counted towards the N requirements for wheat. Beck’s PFR results have shown a wide range of economic optimum nitrogen rates, from 100 to 170 lb. /A. of N, depending upon year and location. Current university research suggests 120 to 140 lb./A. of total N maximizes yield.
Nutrient Removal Rates. Like many crops, wheat removes more nutrients than what is usually supplied by added fertilizers. Some nutrients are supplied by the mineralization of organic matter in the soil. The following chart indicates the amount of nutrient removal to produce a bushel of winter wheat grain. These removal rates do not include nutrients that are removed by baling straw after grain harvest or a double-crop of soybeans. Below is an example of how to determine the amount of fertilizer to apply based on a yield goal or crop removal. Let’s take sulfur (S) for example.
If you are fertilizing for 100 Bu./A. wheat, multiply 100 Bu./A. x 0.1 lb. of S/Bu. = 10 lb./A. of S required.
Now figure your S fertilizer source. If you are using AMS, which is 24 percent S, to get 10 lb./A. of S from AMS you must apply 10/0.24 = 42 lb./A. of ammonium sulfate. Depending on weather, soil organic matter, and S availability in the soil, much of this could be supplied by the soil.
Nutrient (lb. removed/Bu. grain):
Nitrogen (1.2), Phosphate (0.5), Potassium (0.3), Sulfur (0.1), Magnesium (0.15), Calcium (0.025), Copper (0.0006), Manganese (0.0018), Zinc (0.0026), Boron (0.0008), Iron (0.0056)
Weed Control. In some fields, weed control in wheat is not an issue and does not require a herbicide application. Other fields may have competition from henbit, chickweed, wild garlic, wild mustard, or other weeds that require herbicide application. In our geography, one of the best opportunities for weed control is when wheat is topdressed in the spring with liquid UAN. If UAN is being used for topdressing, a herbicide can be tank-mixed, thereby avoiding an additional trip over the field. Many times, adjuvants used with herbicides and liquid UAN may cause temporary leaf “tip burn”. This is common and does not result in yield loss. Be sure to read all label instructions and restrictions regarding herbicide and adjuvant rates, growth stage restrictions, and rotational crop timings.
Foliar Protection/Disease Control. The flag leaf is the most important leaf on a wheat plant, producing and storing at least 75 percent of the nutrients needed for grain fill. The flag leaf is the last leaf to emerge from the stalk prior to the grain head emerging. Keeping the flag leaf, and leaf below it, nutrient-rich and disease-free is a critical step toward high yield. Warm, wet and humid conditions near flag leaf emergence will promote the development of leaf diseases. A foliar fungicide application at flag leaf emergence (Feekes 8) containing both strobilurin and triazole chemistries will provide the broadest, most consistent protection against leaf diseases. Currently, Twinline®, Trivapro®, Quilt Xcel®, Priaxor®, and Stratego® YLD are some of the highest rated combination fungicide products for leaf disease protection in wheat. These fungicides should not be used for prevention of head scab (vomitoxin).
Head Scab Protection/Disease Control. Wheat begins flowering about 14 to 21 days after flag leaf emergence. Warm, wet and humid conditions during flowering can promote the development of Fusarium head scab. This disease survives over winter in infected corn residue and can cause bleached spikelets which usually produce shriveled, lightweight and discolored grain. Even if wheat is planted into soybean stubble, head scab can blow in from other areas. Varieties vary in their susceptibility to head scab. Successful management of this disease first begins with variety selection. Successful management of head scab with fungicides is highly dependent upon fungicide selection and proper application timing. Prosaro® or Caramba® applied at very early flowering (Feekes 10.5.1) have provided the highest levels of control. Beck’s PFR results from 2010-2014 show that Caramba applied at flowering provided a $16.24/A. average ROI with wheat price at $5.50/Bu. Similar positive results have also been found with Prosaro. It is important to note that fungicides containing strobilurin chemistry, for example Headline®, Priaxor, Aproach®, Quilt Xcel, Trivapro, Stratego YLD and others should NOT be applied once wheat begins flowering (Feekes 10.5.1).
The picture to the left shows three wheat heads. The middle wheat head shows infection by Fusarium graminearum, head scab. Notice the bleached spikelets on the upper 80 percent of the head. The wheat heads on top and bottom appear healthy.
Insect Control. For maximum grain yield, it’s important to protect wheat against yield losses caused by insects. Beck’s wheat seed is treated with insecticide, which helps protect against losses from many insects, including aphids that can transmit Barley Yellow Dwarf Virus (BYDV). Aphids, cereal leaf beetles, grasshoppers, and armyworms are insects that must be scouted for in the spring and early summer. If present, armyworms are of a significant concern, not only for their ability to eat large amounts of plant tissue quickly, but also because of their ability to quickly move upward and clip the stem just below the head. Many effective and economical insecticides are available that can be tank-mixed with a foliar fungicide at flag leaf emergence or flowering to protect yield.
The Feekes Scale of Wheat Development. Please use this chart to better understand the Feekes growth stages utilized in the PFR studies on the following pages.
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Author: Chad Kalaher
Categories: Agronomy, NE Illinois, NW Indiana, S. Wisconsin
Tags: Beck's Blog, AgTalk, Chad Kalaher, Agronomy Update, Beck's Agronomist, indiana agronomy, Illinois Agronomy, Winter Wheat, winter kill in wheat, Wisconsin Agronomy, MIDWEST WHEAT, Hessian fly-free date
Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as researc
Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as research agronomist, district, and regional sales manager.