The recent warm weather broke the dormancy
of winter wheat and the crop is actively growing. This
is a very opportune time to evaluate the stand and determine
the extent of winterkill. Evaluating your stand will help
you determine whether to leave the winter wheat stand or
consider replanting with spring wheat or another crop.
To do a stand count, use one of the following two methods:
1. 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.
2. 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
acre.
Table 1 Average number of plants per foot of row for different
row spacing and plant densities per acre
Row Width |
Plants
per acre (times 1 million) |
|
0.8 |
0.9 |
1.0 |
1.1 |
1.2 |
1.3 |
1.4 |
1.5 |
|
|
|
|
|
|
|
|
|
6” |
9.2 |
10.3 |
11.5 |
12.6 |
13.8 |
14.9 |
16.1 |
17.2 |
7” |
10.7 |
12.1 |
13.4 |
14.7 |
16.1 |
17.4 |
18.7 |
20.1 |
10” |
15.3 |
17.2 |
19.1 |
21.0 |
23.0 |
24.9 |
26.8 |
28.7 |
12” |
18.4 |
20.7 |
23.0 |
25.3 |
27.5 |
29.8 |
32.1 |
34.4 |
Table 2 Adjustment factors to multiply the number of plants
inside a hoop and convert the number to number of plants
per acre
Hoop Diameter |
Multiply by |
|
|
30” |
8,900 |
32” |
7,800 |
34” |
6,900 |
36” |
6,200 |
38” |
5,500 |
Page 47 of the Small Grains Field Guide mentions the general
rules for replanting decisions. Use the following guidelines
to determine whether replanting is worthwhile:
1) If reduced stand is uniform (no big skips or holes)
keep stands at 15 plants per square foot.
2) If skips are large (3 to 6 ft), or holes are 4 to 6
feet in diameter and stand is 18 plants per square foot
or less, then replant if moisture is adequate.
The amount of winterkill in the Winter Wheat Variety Trials
in Crookston and Fosston was negligible this past winter.
Most damage appeared to be caused by deer grazing. Both
trials were planted into soybean stubble in the first couple
of days of October last fall. Initial stands were recorded
in the third week of October. At that time, the seedlings
had barely reached the first leaf stage. The stands were
recorded again this week. The stands last fall averaged
19.5 plants/ft2, some 5.5 plants/ft2 less than intended.
Not all seedlings must have emerged at the time the stand
were recorded last fall as stand counts improved to an
average to 20.5 plants/ft2 when stands recorded earlier
this week.
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