In last week’s blog post we discussed stalk strength. Hopefully we won’t have many areas with serious problems with lodged or broken stalks, but from there always seems to be a few areas where we have unintentionally left grain in the field. Sometimes these losses come from ear loss and at other times loose kernels get by the cylinder and sieve and never get to the bin. Growers should regularly check for harvest losses to determine if they are significant, and if so, if they resulted from early ear drop (a corn hybrid concern) or from maladjustment of the combine.
The procedures for determining losses are as follows. To determine ear loss, stop the combine 300 to 500 feet into the field. The crop in the area where you stop should be somewhat representative of the overall field. Stop or disconnect the straw spreader and do not clear the combine. Ear losses will be determined by gathering fallen ears from 1/100th of an acre immediately behind the combine, and possibly immediately in front of the combine if ears or stalks lay on the ground. Perhaps the easiest means of measuring 1/100th of an acre is by counting all the ears left on the ground within a single row. Of course as your row width varies so will the length of the area in which the count is made. For 20 inch rows, you would need to count ears between any two rows for a distance of 262 feet. For 30 inch rows, you would need to count ears between two rows for a distance of 187 feet. And if you are a math wizard, you can double the width of the area where you count lost ears and halve the distances mentioned. If you know the length of your stride, you can pace off the distance as you walk away from the combine and then count ears as you walk back. Each 3/4 lb ear represents one bushel per acre lost. Any significant difference between the number of ears behind the combine compared to those on the ground in front of the combine could indicate a problem with the combine header.
Loose kernels can also be a source of significant losses. To determine if kernels are getting by the sieve, you may have to kick aside some of the stover and count kernels. While not an exact measurement of loss, approximately 2 kernels per square foot equals 1 bushel per acre left in the field. Under typical conditions we should expect less than 1 bushel per acre to be left in the field. If you suspect more than that remains some consideration should be given to sieve, cylinder, or header adjustments.
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