By Dennis Pennington
Late fall planting coupled with a cold, harsh winter has farmers wondering how their wheat crop will fair once it starts to green up. Typically, we want to see two to three tillers in the fall before wheat goes dormant. In many cases, only the coleoptile has emerged. With the lack of tiller and root development last fall, farmers should scout and evaluate their crop before making any decisions about destroying their wheat to plant another crop.
Wheat is resilient and can tolerate very cold temperatures. Overwinter survival will vary across each field. Topography and residue coverage can vary. Areas with taller residue (stubble) as well as low areas can trap snow, which provides additional insulation. However, water ponding and icing in low areas can suffocate the crown. Make sure you check over the entire field, not just headland areas.
Timing of scouting is important. Wheat breaks dormancy after 50 consecutive hours above 48 degrees Fahrenheit. Crop scouting efforts should occur after green-up begins. It is too early to tell in the field this time of year. If you want to know if a crown is alive now, dig some plants, bring them inside, clip the top growth off and keep them watered. You should see the plant begin to grow in four or five days.
Scouting procedure
You cannot scout fields from your vehicle. Get out and walk around each field and conduct a set of stand counts that represents the entire field. When conducting stand counts:
- Measure 3-feet rows.
- Count and record the number of plants.
- Calculate the average number of plants per foot.
- Count in three to five locations per field.
Count plants in 3-feet rows. Wheat is too variable if you only count 1 foot. Use a yard stick and lay it down next to a row and begin counting. Try not to purposely count only good or only bad areas. You want to get a good average in order to make proper management decisions. Count 3-feet rows in three to five locations in each field and use the average to determine the plant stand per 1 foot of row. For stand counts, make sure you only count live plants, not tillers. Make note of how many tillers you have as that will help you adjust nitrogen timing. Reference Table 1 for an estimation of yield potential based on plant stand counts.
Table 1. Plant stand counts for four row spacings and their relation to percent of yield potential. |
|---|
Plants per foot | Percent of yield potential |
|---|
6-inch rows | 7-inch rows | 7.5-inch rows | 10-inch rows |
|---|
12-14 | 14-16 | 15-18 | 20-23 | 100 |
9-11 | 11-13 | 11-14 | 15-19 | 90-95 |
8-9 | 9-11 | 9-10 | 13-14 | 75-80 |
6-7 | 7-8 | 8-9 | 10-12 | 60-70 |
3-6 | 4-6 | 4-7 | 5-9 | 40-50 |
Adapted from Table 3-4 of the University of Kentucky Extension Bulletin ID-125, "A Comprehensive Guide to Wheat Production in Kentucky."
Early nitrogen
Degree of tillering is a useful tool in determining the timing of spring nitrogen on wheat. Ideally, wheat should produce two to three tillers in the fall. Fall tillers typically provide higher yield potential compared to spring developed tillers. In fields with two to three tillers, make a single application of nitrogen at Feekes 5-6 (prior to jointing).
In fields with less than two to three tillers, put on 50-60 pounds of actual nitrogen at green-up; with the balance based on yield goal, put on at Feekes 5-6 (prior to jointing). Table 3 contains Michigan State University Extension fertilizer recommendations for nitrogen rates on wheat based on yield goal. Use a realistic yield goal considering the current crop condition.
When applying green-up applications, make sure frost has gone out, then apply when overnight temperatures get down to 20-25 F and apply early in the morning to avoid damage to field. Time application so that the ground will thaw the next day, reducing the chance of fertilizer washing off frozen ground in a rain event. Pay attention to weather forecast and do your best to keep your nitrogen on your field.
Table 2. Recommended nitrogen rates are based on the formula nitrogen = -13 + (1.33 x yield potential). |
|---|
Yield Potential (bu/a) | Nitrogen (pounds/a) |
|---|
60 | 67 |
70 | 80 |
80 | 93 |
90 | 107 |
100 | 120 |
110 | 133 |
120 | 147 |
Scout for weeds
Late planted wheat with little or no tillering may be subject to increased weed pressure. The lack of early canopy cover may allow winter annuals to germinate and get a foothold where timely planted wheat may be able to overcome and outcompete with these weeds. When conducting stand counts, make note of weed pressures and determine a timely weed control plan. For more information on weed control in wheat, visit MSU Extension's Wheat Weed Control website.
Source: msu.edu