The harvest of summer crops is moving at a rapid pace and producers will begin thinking about planting winter wheat. Below are some pointers and reminders about wheat production in Tennessee.
VARIETY SELECTION
It is wise to select a variety that has been tested and evaluated under Tennessee conditions. Consider the characteristics of each variety, then select the variety or varieties that best suit the conditions on your farm. Varieties tested in Tennessee and the varietal characteristics at all research locations can be found at:
2012 Wheat Variety Test Results
VARIETAL CHARACTERISTICS
Maturity: Maturity can be defined in different ways. Depending on the growing season, a medium-maturity variety might be ready to harvest within two to three days of an early-maturity variety planted on the same date. An important consideration is that early varieties will joint and head earlier. Therefore, they are more susceptible to stem and head freeze in March and head freeze in April if planted too early in the fall.
Seeding: Unless only a small acreage is involved, it is always a good idea to plant more than one variety to spread risk. Plant two to three of the top varieties for your area, depending on your acreage. Variations in pest severity and weather conditions will favor one variety over another in any given year. When trying a new variety for the first time, you should usually plant the majority of your acreage in a proven performer.
Certified Seed: Use of certified seed provides a level of insurance against poor germination and introduction of weed seeds. Bin run seed may be of inferior quality and purity of variety is guaranteed.
Seedbed Preparation: Wheat requires a firm seedbed with enough loose soil to cover the seed to a depth of 1 to 1.5 inches. Disking to a depth of 2 to 4 inches is usually all that is necessary in preparing a seedbed for wheat where it follows corn, soybeans, grain sorghum or other row crops. When it is necessary to plow, the land should be plowed far enough in advance of seeding to allow for development of a firm seedbed with conventional practices. Where erosion is a problem with conventional seedbed preparation, wheat can be planted no-till with excellent results. A preplant burndown herbicide should always be applied prior to planting when weeds are present.
SEEDING DATES AND RATES
Dates: For best winter survival and top grain yield, plant wheat from October 15 to November 10. Do not plant wheat until after the fly-free date of October 15. Wheat should be planted early enough for young plants to become well-rooted and develop 3 to 4 inches of top growth before going into the winter (December 21st). Research indicates that planting during the latter half of the recommended planting period or planting treated seed (systemic insecticide) reduces the incidence of barley yellow dwarf by avoiding or controlling aphids that transmit the virus to wheat. In most Tennessee fields, an insecticide seed treatment will at least pay for itself by controlling early-season aphid populations.
Rates: Wheat seeding rates vary from 1.5 to 2.0 bushels per acre depending upon the condition of the seedbed, time of seeding, quality of seed and method of seeding. A seeding rate of 2 bushels per acre should generally be used. Increase the rate to 2.0 to 3.0 bushels per acre (1) if seed are broadcast, or (2) when seeding is delayed until November 1st. Ideally, you want to end up with 1.3 to 1.5 million plants per acre. This seeding rate can be calculated by dividing the desired population by the percent germination printed on the bag to obtain how many seed need to be sown. Then divide by the number of seeds per pound to get the number of pounds of seed needed per acre; then divide the number of pounds per acre by 60 pounds (number of pounds of wheat seed per bushel) to get the number of bushels per acre needed.
Example: Desired population 1,300,000 (1.3 million) plants per acre.
Seed germination percentage = 85 percent
Number of seed per pound = 12,000
Number of pounds per bushel = 60
1,300,000 ÷ 0.85 ÷ 12,000 = 127 lbs seed per acre
127 lbs seed per acre ÷ 60 lbs per bushel = 2.12 bushel per acre
| Use* | Seeding Rate | Seeding Date/Method |
| For grain or springgrazing | 1.5 – 2.5 bu.1.5 – 2.5 bu.2-3 bu. | October 15-November 10no-till drilledOctober 15-November 10conventionalOctober 15-November 10Over-seeded, no-tillage |
| For winter cover | 1-1.5 bu.1-1.5 bu.1-1.5 bu. | September 15-November 10no-till drilledSeptember 15-November 10Over-seeded, no-tillageSeptember 15-October 20Conventional |
| For cover, wildlife enhancement or fall grazing | 2-3 bu. | August 15-October 1 Over-seeded |
| *Use higher seeding rate if seeding under adverse conditions. Increase seeding rate by 50 percent if using bin-run seed. | ||
Method and Depth:Sowing wheat with a drill instead of broadcasting insures a more uniform depth of covering, higher germination, less winter injury and generally higher yields. Drill or cover wheat to a depth of 1 to 1.5 inches when adequate moisture is available. When soil is dry, a slightly greater depth is advisable, but should not exceed 2 inches.
Broadcast Seeding: The two most important aspects to consider when broadcast-seeding wheat are to insure that adequate seeding rates are used and that good seed-to-soil contact is established. To accomplish these goals, 2 to 3 bushel of seed should be broadcast uniformly and incorporated by a shallow pass with a “do-all” or similar equipment. Seed that are broadcast and left lying on the soil surface are subject to animal predation, poor germination and frost heaving. All will lead to a loss of stand.
FERTILIZATION
Apply lime and fertilizer based on soil test recommendations. If lime is needed, it should be applied before seeding. All the phosphate and potash can be applied immediately before or at planting (Table 3). When double-cropping wheat with grain sorghum or soybeans, the fertilizer should be applied to the soil with the total amount of phosphate and potash needed for both crops prior to planting wheat. Apply 15 to 30 pounds of nitrogen at seeding time to stimulate vigorous plant growth. Apply 30 to 60 pounds of nitrogen as a top-dressing February 15-March 30. Use the earlier date if the wheat stand is thin to encourage more tillering. All the nitrogen should be applied before wheat begins to joint. Research has shown no difference in source of nitrogen (ammonium nitrate, urea or liquid nitrogen) when applied according to recommendations. Total economical nitrogen needs for a wheat crop grown in Tennessee should be between 45 to 90 lbs. per acre.
Consider split-applying the top-dress nitrogen application when wheat is planted after November 15 or when there is an average of less than four tillers per plant in early January.
| Soil test level |
Wheat alone |
Wheat with double-crop beans |
||
|
P(P2O5) |
K(K2O) |
P(P2O5) |
K(K2O) |
|
| Low |
80 |
40 |
90 |
120 |
| Medium |
40 |
20 |
60 |
60 |
| High |
0 |
0 |
0 |
0 |
| Very High |
0 |
0 |
0 |
0 |
| *Nitrogen should be applied from 45 to 90 lbs per acre. | ||||
HIGH-INPUT PRODUCTION SYSTEMS
Some wheat production systems look to maximize yield potential by utilizing crop protection chemical and fertilizer inputs at increased rates when compared to UT Extension recommendations. UT Extension recommendations attempt to maximize economic returns for wheat producers by only applying inputs that have been proven to provide economic returns over multiple years of research. UT Extension recommendations are based on using sustainable practices including proper scouting with Integrated Pest Management (IPM) programs, soil testing and reasonable yield goals. UT Extension discourages the use of any management system that requires inputs based on calendar dates without appropriate scouting or testing procedures.
While high-input systems are attractive when high yields are realized, producers need to evaluate how much monetary risk they are willing to take in their management budget. The most important decision you make with either a high-input or traditional production system is to stick to your original plan. Using a traditional system and attempting to increase nitrogen fertility will usually result in lodging. Likewise, starting with a high-input system and deciding late in the season to abandon your plan will result in losing the previously applied inputs. Choose a system that fits your production needs and manage the crop accordingly.
Chris,
Where we’ve pulled corn yields ranging from 10-30 bu/A, we still have quite a bit of Nitrogen left in the field. How much attention do we need to pay to the fact that, in some cases, we’ve had nitrate tests come back as high as 50 units still available? How much do you think the residual nitrogen from will play into our total of 90 units? Thanks Chris.
Tyler
Tyler
Great question. While nitrate tests can vary widely from day-to-day or week-to-week it is currently the only way we have to get an estimate of available nitrate in the soil. How much is available to the wheat crop will depend on how much rain we get between the sampling date and wheat planting. The more rain we get the more can be lost to leaching, but also in the breakdown of corn residue by micro-organisms. We currently use a rule-of-thumb of 20-30 lbs of available nitrogen from a preceeding soybean crop (due to nodulation). In your case I would credit no more than 30 lbs of nitrate to your wheat crop since it is readily available and will mostly impact wheat establishment. I highly suggest conducting a tiller count near Christmas, if you ave 4-5 (or more) tillers per plant you have great yield potential and the crop is using the available nitrogen. In this situation continue to add the balance of the nitrogen fertilizer in early-mid February. If your tiller count is low (2-3 per plant) you most likely have not been able to utilize the residual nitrogen and should plan to make a split application of 45 lbs N in mid-January to stimulate tillering and apply the remining 45 lbs of N in mid-February to achieve high yields.
What are your thoughts on blending fertilizer with the wheat when broadcasting? Most common blends in our area are 30-40-80. Do you know of any problems with this practice?
Neil
There should not be any problems with this approach as long as you get a good blend of seed and fertilizer, you are able to manage the bulk material to get an even spread, and finally the producer is willing to incorporate the seed for optimum germination and winter survival.