Evaluating Your Winter Wheat and Rye Stands
April 16, 2018
As wintery weather persists, you may wonder if your winter wheat or rye has survived this winter. If you are really anxious or bored, you can dig up some crowns across the field and cut them longitudinal (lengthwise) with a very sharp knife or a safety razor blade. If the crowns look white/yellow to light green, they are healthy and have survived the winter to date. If you find crowns that have turned tan to brown and soft, they likely did not survive this winter. A second method to check whether seedlings are alive is by trimming the roots and leaves down to about ¼ to ½ ” above and below the crown. Place these seedlings on a wet paper towel and place the towel in a Ziploc bag or plastic container that can be sealed. Place the container at room temperature and check for regrowth in 48 hours. Viable seedlings will show regrowth almost immediately (Photo 1).
Photo 1 – Regrowth of young winter wheat seedlings after 36 hours incubation in a Ziploc bag at room temperature (photo courtesy of Blake Vandervorst)
Unfortunately, checking a single or a few crowns does not tell the whole story as winterkill is often patchy across a field (Photo 2). To determine whether you need a plan B for these fields requires you to wait until the field starts to green up sufficiently in order to do a reliable stand count. The more protected areas will green up first, while bare knolls or lower lying areas where water or ice may have been present sometime during the winter and early spring will be slowest to green up.
Photo 2 – Area with partial and uneven winter kill (photo courtesy of Joel Ransom).
To do a stand count, use one of the following two methods:
- Count the number of plants in a foot of row at several locations in the field. Take an average and convert in plants per acre using Table 1.
- Take a hula-hoop, let it fall, and count the number of plants inside the hoop. Repeat this at random several times across the field and calculate an average. Use Table 2 to convert the count to an approximate population per square foot or acre.
Table 1 – Average number of plants per foot of row for different row spacing and plant densities per acre.
|Plants per acre (times 1 million)|
Table 2 – Adjustment factors to multiply the number of plants inside a hoop and convert the number into the number of plants per acre.
|Hoop Diameter||Multiply by|
Uniform stands of 17 plants per square foot or approximately 750,000 plants per acre are sufficient to keep and do not require a plan B. Consider replanting only those areas of the field where stands are below the threshold with, for example, spring wheat. No-till seeding HRSW into standing HRWW is possible but creates some challenges later in the season because the two crops will reach growth stages at different times and complicate not just harvest but also the timing of herbicides and fungicides.
Source: University of Minnesota Extension: Minnesota Crop News