Wheat stand evaluation


COLUMBUS – In the northwest section of Ohio, wheat producers will be determining if the stands are sufficient to keep for harvest. This is because wet weather in October and seedling diseases caused severe losses in stands in a widespread area primarily west of Interstate 75 and north of State Route 30.

Assessing a less than optimal stand of wheat is difficult, especially this year with plants of various ages and numbers of tillers in replanted fields. Estimating yield from numbers of tillers per foot of row this early is difficult because we do not know what the weather has in store for the crop through spring.

Predicting yield. Yield is a function of the number of heads per acre, seed per head and weight of seed. Wheat has a tremendous capacity to compensate for stand. The largest heads with the most seed are on the main tillers, usually those tillers are produced in the fall. Thus, the more large heads the higher the yield.

Counting tillers now, in March, may or may not provide a good estimate of the yield potential of a field. Wheat has the capability to produce new tillers until the stem elongation growth stage (Feekes growth stage 6) in mid April. Also, not all the tillers will develop heads. For this reason, tiller counts are relative and are only an indicator of potential yield.

Since we cannot count heads in March, but we can count plants and tillers, we need to make some assumptions. If 9 plants per foot of row each have the capacity to produce three tillers, for a total of 27 tillers with heads per foot of row, the yield potential would be in the 65 bushels/acre range.

However, if these same 15 plants only produce two tillers, the yield potential would be about 45 bushels/acre. As you can see, an acceptable yield can turn into an unacceptable yield based on how many head bearing tillers develop later this spring.

Check all fields. Each field should be examined individually. Those fields that have lost stand in large areas or patches present big problems and are prime candidates to be converted into another crop.

Assuming there was relatively uniform loss of stand in the field over winter, we would estimate that 10 to 13 plants per foot of row would provide an economic stand at this time, especially if each plant was capable of producing 3 or more tillers.

Obviously growing conditions this spring; fertility level, weed pressure and disease will have an impact on the actual yield. Producers should also consider alternate uses for the field (i. e. soybeans, corn, alfalfa), rotation sequences, and pest control (i.e. soybean cyst nematode infestations) when making the decision to keep the wheat or plant another crop.

Source: OSU’s Pat Lipps/Jim Beuerlein

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