Early spring assessment of wheat to estimate yield potential

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

An estimate of the yield potential of individual wheat fields during early spring is an important basis for management decisions. Plant density, along with considerations for production factors, can be useful in establishing a reasonable approximation.

Plant density within a wheat stand is usually the single most important indicator of yield potential. However, determining the number of live plants during green-up is not always easy, especially where winterkill is suspected. For example, brown and dried leaves do not necessarily indicate winterkill as these fall-generated leaves can be killed without reducing the plant’s chance for survival. On the other hand, an initial flush of green top-growth does not guarantee a plant will survive. The reason for this is that temperatures are sometimes cold enough to destroy the crown’s ability to grow new roots, but not cold enough to destroy the more resilient shoot-regenerating part of the crown. Fields that appear to be damaged should be revisited one or two weeks following green-up to determine if plants have actually survived.

Where winterkill is a factor, wheat plants should be inspected for new white roots growing from the crown. To speed the process, plants can be taken from the field and, after removing the soil, held at room temperature. To insure that the crown and roots remain moist, a paper towel or sealed plastic bag can be used. After four days, a viable crown should be producing new roots.

Once the density has been estimated, the table can be used to suggest a range of potential yields. The table provides yield estimates as a percent of that normally attained under good agronomic conditions. For each plant density, the yield potential is given in a “low-estimate” and a “high estimate” column. The lower yield potentials should be considered when an individual field is exposed to significant yield-limiting circumstances. For example:

  • Fields that were planted four weeks or more beyond the Hessian fly-free date (delays to this extent often result in yield reductions of 10 to 20 percent);
  • Wheat seedlings experienced repeated and prolonged periods of saturated soils (common poorly drained or non-tiled fields); and
  • Fields where adverse winter conditions injured plants (“winter injury” as opposed to “winter kill”) exhibiting slow development, poor coloring and generally poor vigor.

The suggestions provided here should be tempered, of course, by a grower’s experience. Consideration should also be given to the assessments of other veteran growers or experience field personnel that can visit the field in question.

Early spring estimates of wheat’s yield potential at low and high levels

Plant density

Yield potential %

 Plants / ft (7 ½” row
 spacing)

Low estimate

High estimate

5

50

65

6

52

70

7

55

75

10

59

80

15

64

90

22

70

100

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