| By Ed Corrigan
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Post pollination scouting in corn fields has alarmed growers throughout the Brandt trade area with the discovery of poor kernel set in neighborhood corn fields. Growers’ interest in this topic obviously lies with the fact that the number of kernels per ear is a rather important component of total grain yield per acre. For example, the loss of only 1 kernel per row for a hybrid with a 16 row ear and stand count of 30,000 would equate to a 5 bushel per acre loss.
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Problems with kernel set is a result of ineffective pollination, kernel abortion, or both. Distinguishing between these two symptoms is easy. Determining the exact cause of kernel set is sometimes difficult. Good to poor kernel set is determined from pollination through the early stages of kernel development; typically 2 to 3 weeks after pollination. Kernel abortion results from severe stresses that greatly reduce the photosynthetic output of the plant very early in the post-pollination process.
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Obvious photosynthetic stressors include severe drought & heat stress, consecutive days of excessively cloudy weather and significant loss of photo-synthetically active leaf area. (i.e. hail damage, leaf diseases, insect damage, and nutrient deficiency).
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| The pollination and grain set for most corn fields in 2008 was ideal other than one of the previously mentioned stresses: |
Nutrient Deficiencies
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Potassium and Boron are both very instrumental to grain fill by increasing photosynthesis and improving nitrogen efficiency.Potassium also assists the corn plant with heat stress conditions by adjustment of stomatal movement on the bottom of the leaf.
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The soils collapsed during the wet spring and trapped the potassium between the soil colloids, reducing uptake during the vegetative growth stage. This trapping was a result of the 2008 environment. Potash deficiencies in the future can be reduced by using proper tillage, good potash soil management, and a good freeze and thaw over the winter.
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| Boron improves crop quality and increases crop disease resistance. Boron deficiencies can be corrected with foliar applications. |