Evaluating seedling wheat stands

Walking fields of young wheat stands can help critique a grain drill’s performance and settings.

Evaluating seedling wheat stands

Much of a wheat crop’s yield potential depends in part on a consistent and uniform stand of healthy seedlings. Michigan State University Extension suggests walking wheat fields to evaluate drill settings and performance based on the number and appearance of emerging seedlings.

The ultimate goal when seeding is to achieve a uniform stand as soon after planting as possible (not unlike one’s goal for row crops). The causes of gaps and unevenness, such as crop residue, traffic or drill performance, should be noted so corrective action can be taken next fall. Also, it is worthwhile determining seedlings per foot of row (this exercise is much easier if performed prior to extensive tillering). Generally, early planted wheat would have 14 to 20 plants per foot of row (7.5-inch row spacing), whereas one might aim for 22 or more seedlings where sown in mid-October (Photo 2).

Closeup of wheat stand

Photo 2. Cclose evaluation of wheat stands can help in making corrective adjustments.

Knowing the number of seedlings per foot of row, it is helpful to see how closely it aligns with the intended seeding rate and drill setting. The table below can serve as a reference. For example, if a grower feels they were dropping 1.8 million seeds per acre (26 seeds per foot of row), but finds an average of less than 20 seedlings per foot, it would be worthwhile to determine the reason. In some cases, it might be due to an over-estimation of seeding rate. In other situations, it may be associated with difficulties in germination or emergence. Whatever the cause, hopefully the observations can lead to corrective adjustments before next season.

Comparing actual seedlings population to seeding rate.

Seeding rate (millions/ac)

Seeds per foot of row*

Seedlings per foot of row**

1.4

20.1

18.5 (92%)

1.6

23.0

20.7 (90%)

1.8

25.8

22.7 (88%)

2.0

28.7

24.7 (86%)

2.2

31.6

26.5 (84%)

 * Target seeding rate/43,560 X 0 .625 = seeds per foot of row (7.5-inch spacing).
** Average number of seedlings (assumed emergence rate in parentheses).

Obviously, this evaluation is most constructive if you create a record of the planting operation for each field. This record would at least include variety, seed size and drill settings. An example is available at “Records for evaluating seeding operation and seedling stands.”

Checking seedling depth is also worthwhile and often instructive. The actual depth of seed placement can be estimated by observing the seed in relation to the crown. Where the seed is next to the crown, you can surmise that the seed was placed a half-inch or less below ground. Where a mesocotyl is visible between the seed and crown, its length plus another half-inch approximates the seed’s original depth (Photo 3).

The seed on the right was placed a half inch or less in depth, whereas the seed on left was nearly 2 inches deep based on length of mesocotyl.

Photo 3. Seed depth can be estimated by looking at seed in relation to the crown. The seed on the right was placed a half inch or less in depth, whereas the seed on left was nearly 2 inches deep based on length of mesocotyl.

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