Evaluating young wheat stands

Keyword: seed, Wheat, Crops/Farming/Woods
Publish time: 20th November, 2014      Source: Michigan State University Extension
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Getting out of the truck and walking across winter wheat stands can be helpful in assessing seeding rates, drill performance and prospect of a profitable crop.

     
Sixteen plants per foot of row may be adequate for mid-September planting, but as planting is pushed later in the fall, populations should be considerably higher.

Sixteen plants per foot of row may be adequate for mid-September planting, but as planting is pushed later in the fall, populations should be considerably higher.

  

Much of a wheat crop's yield potential is determined by the time wheat emerges in the fall, so Michigan State University Extension suggests growers take time to evaluate their young wheat. From the road, one can get a general sense of the health and uniformity of a young wheat stand. However, in-field inspection is necessary to fully evaluate the outcome of one's seeding practices.

When stepping into the field, one place to start is counting the seedlings per foot of row. Generally, early planted wheat would preferably have 15 to 20 plants per foot of row, or 7.5-inch row spacing, whereas one might hope for at least 25 seedlings when sown after mid-October. Another worthwhile determination would be to see how the number of seedlings match up with the estimated seeding rate. The table below can serve as a reference. For example, if a grower feels they were dropping 1.8 million seeds per acre, or 26 seeds per foot of row, but only finds an average of less than 17 seedlings per foot, it would be worthwhile to determine why there was only two of three seeds produced a seedling.

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 seedling rate.

Seeding rate (millions per acre)

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).

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, one can surmise that the seed was 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.

Wheat crown
Seeding depth can be estimated by observing the seed in relation to the crown. The seed for the plant on the right was placed less than a half-inch from the soil surface, whereas the seed for the plant on the left was placed nearly 2 inches in depth based on the length of the mesocotyl.

A factor often more important than plant population or seed depth is the consistency of the stand. The goal is to achieve consistent and rapid emergence, and evenly spaced seedlings – not unlike the goal with corn – to the extent possible using planter units that do not singulate seed. The causes of gaps and unevenness, such as crop residue, traffic or drill operation, should be noted.




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