| | An early estimate of grain and oilseed crop yield is a key component in addressing whether or not stressed crops are economically worthwhile to harvest. Keeping in mind, the more uneven the growth, the more difficult it is to calculate a yield estimate that is representative of the field. The following procedure outlines how this can be done.
Estimating crop yield
The first step is to determine an area representative of actual production and count the number of heads/pods within that area. AFSC crop insurance adjusters use a square yard because it provides a better representation of yield than a square foot. Then count the numbers of kernels/seeds that are filling per head/pod, take an average from a minimum six heads/pods in that area. Take a minimum of five square yard counts in a quarter section field (yd2 =9ft2 or 3ft x 3ft).
The next step is to estimate the kernel/seed weight. Generally, a standard 1,000 kernel weight can be used (see Table 1).
Samples can also be weighed to establish your own 1,000 kernel weight. This is easily done by averaging the weight of 100 kernels weighed three times, and then multiply by 10 to get your 1,000 kernel weight.
Table 1: Approximate 1,000 Kernel Weights, by Crop1
1 Source: Alberta Agriculture and Rural Development, "Using 1,000 Kernel Weight for Calculating Seeding Rates and Harvest Losses,"
Agdex 100/22-1, Revised Aug., 2007
Finally, the counts and weights can be entered into this formula to estimate yield in Kg/Acre*:
Yield = heads/yd2 x kernels/head x 1,000 kernel weight (in grams) x 0.00484
Example: using HRS wheat with counts of
225 heads/yd2, 26 kernels/head and a 1,000 kernel weight of 34 grams, the yield works out to:
= 225 x 26 x 34 x 0.00484
= 963 Kg/Acre
Given wheat at 36.75 bushels per tonne, the estimated yield would be about 35 bushels per acre. (963 x 0.03675 = 35.4)
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Questions:
Please call the Ag-Info Centre at 310-FARM |
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