44 Story Idea? Email Paul.Nolan@Farms.com Better Farming | January 2025 I have often written on the yield components in corn, consisting of the number of cobs per acre, the number of kernels per cob, and the weight of the kernels. The thousand kernel weight (TKW), as the name implies, is the weight of a thousand kernels of corn. In this case, expressed in grams, the TKW can vary based on hybrid and environmental growing conditions. Each year, we collect samples from our hybrid corn plots and determine not only yield and harvest moisture but also TKW and DON mycotoxin levels. The results from 2024 were a bit unexpected at first glance. Usually there is a strong correlation of TKW to yield. We had such a narrow distribution of values that the relationship was not showing a strong correlation. There was a very narrow range in the attributes measured. As a result, there was minimal variation or differences among the test plots in 2024. This is not to say there aren’t differences at the field level. The TKW is often an indication of how well the grain fill period progressed. Overall plant health and crop nutrition plays a role, as does adequate moisture and sunshine to drive photosynthesis and produce the necessary sugar to fill kernels. Field environments and management play a role, too. As an example, a single hybrid TKW ranged from a low of 330 to 394 grams, or kernels per bushel of 77,042 down to 64,527, and yields of 213 to 241 bushels per acre, respectively. Figure 1 shows that the average yield on 133 data points was 233 bushels per acre with a variance of plus or minus 20 bushels or a range of 213 to 253 bushels at one standard deviation. The harvest moisture averaged 18 per cent with a range of 16 to 20 per cent. The TKW averaged 377 grams and ranged from 354 to 400 grams, and, finally, the number of kernels per bushel averaged 67,437 and ranged from a low of 63,237 to a high 71,637. Overall, a tight distribution of attributes. The fall weather was a great equalizer in tightening up dry-down rates and improving grain fill. The TKW was slightly higher for the long-day hybrids of greater than 100 days of relative maturity, as they tend to have a longer grain fill period. The test plot sites tend to be some of the best field conditions on purpose. We want to remove as many variables as possible to look at hybrid attributes alone. 2024 CORN YIELD: TKW & WEATHER INSIGHTS Fall weather & field conditions shaped 2024 harvest. By Dale Cowan crops: yield matter$ Dale Cowan photo Tar spot weakens stalk integrity, making harvest difficult. Figure 1 Average 233 18 377 67,437 Yield (bpa) Moisture TKW (g) Kernels/ % bushel Standard Deviation 20 2.3 23 4,200 Coefficient Variation % 8 6 6 6
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