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Is That Crop Worth Harvesting? | |
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From the Sept 28, 2009 Issue of Agri-News | |
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| | 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 that 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 an estimate can be done.
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The first step in estimating crop yield 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. Next, 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 (yd 2 = 9 ft 2 or 3 ft x 3 ft).
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.
Finally, the counts and weights can be entered into this formula to estimate a kg/acre yield in kg/acre*:
Yield = heads/yd2 x kernels/head x 1,000 kernel weight (in grams) x 0.00484
For 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 like this, 225 x 26 x 34 x 0.00484 = 963 kg/acre. Given wheat weighs in at 36.75 bushels per tonne, the estimated yield would be about 35 bushels per acre (963 x 0.03675 = 35.4). The logic for the calculation is looks like this:
Kernels/Acre = heads/yd 2 x kernels/head x 4840 yd 2/ac
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Grams per acre = kernels per acre x kernel weight
1,000
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kg/acre = grams per acre
1,000 |
*AFSC uses kg/acre for insurance purposes
Tables providing the approximate 1,000 Kernel Weights by Crop are available on Alberta Agriculture and Rural Development’s website at www.agriculture.alberta.ca and search Kernel Weight by Crop.
Contact:
Karla Bergstrom
Production crops economist
Alberta Agriculture and Rural Development
780-422-3122 |
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For more information about the content of this document, contact Karla Bergstrom.
This document is maintained by Rita Splawinski.
This information published to the web on September 24, 2009.
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