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Corn Development and Yield: Dry Conditions Can Reduce Kernel Size

By Jeff Coulter, Extension Corn Agronomist

Much of the corn in Minnesota is in the dough stage of kernel development. At this stage and beyond, stress to corn from dry conditions reduces yield by decreasing kernel size. Kernel number is not reduced due to stress during the dough stage, since that has already been established.

Corn development in Minnesota and much of the Corn Belt continues to remain behind that of last year and the 5-year average. Although warm temperatures advance corn development and reduce risk of corn being immature before a killing freeze, warm temperatures can shorten the duration of grain filling and therefore result in lighter kernels, especially when combined with dry conditions. 

To evaluate the impact of this season’s weather on corn development and yield potential, researchers from the University of Nebraska ran a crop simulation model on August 21 for 37 locations across the Corn Belt, including three from Minnesota. Results are available at: August21 Corn Yield Forecasts

These forecasts indicate a low probability of below-average corn yield at most sites across the Corn Belt where planting was not exceptionally delayed. However, excessive early-season rainfall that occurred in many areas is expect to result in considerable variability in corn yield among fields and regions. A final set of yield forecasts and an analysis of the growing season is planned for early September.

More educational resources on corn production are available at Extension's Corn Production website.

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