Editor’s note: The following was written for the University of Nebraska Crop Watch website Sept. 19.
To evaluate the impact of this season’s weather on corn yield and its variability across the Corn Belt, simulations of 2019 real-time crop stage were performed for 37 locations across the Corn Belt using a University of Nebraska Hybrid-Maize crop model.
Corn had reached black layer at most locations, except for the northern (northern Iowa and Nebraska, Minnesota and North Dakota) and eastern (Ohio, Indiana, Michigan and eastern Illinois) regions of the Corn Belt.
During the last month, most locations exhibited near-normal rainfall except in North Dakota, Minnesota and a few sites in Nebraska that showed above-normal rainfall.
Night temperature tended to be above normal in all states except for those in the northern fringe of the Corn Belt (North Dakota, Minnesota and Michigan), where night temperature has remained near normal.
About 40% of the irrigated sites exhibited near-average yields in southeast Nebraska and Garden City, Kansas, and most likely will in northeast Nebraska. Three sites presented above-average yields (Silverlake, Scandia and McCook), which is also the most likely scenario in western Nebraska.
Northern sites in Nebraska, where corn has not already matured, still have a small chance of below-average yield associated with frost-damage risk, but, overall, they also look like they will reach near-average yields.
Forecasted end-of-season yields for rainfed corn indicate above-average yield at two-thirds of the sites, with yields well above historical averages in Nebraska, Kansas and Missouri.
In contrast, most sites in Iowa and Bondville, Illinois, are forecasted to be near average. Only one site (South Charleston, Ohio) is expected to be below average. In the case of Michigan, there is a high probability for yield to be below or near average.
Overall, it looks like a good year for corn at most sites for which we performed the yield forecasts, except for one site in the eastern fringe of the Corn Belt. Still, note that these forecasts do not take into consideration problems with stand emergence, hail/flooding damage, replanting situations, disease or nitrate leaching. In fields negatively affected by these constraints, actual yields will be lower than estimates provided here.
It is important to keep in mind yield forecasts are not field-specific and, instead, represent an estimate of average on-farm yield for a given location and surrounding area in absence of the yield-reducing factors mentioned here.
Likewise, crop stages and forecasted yields will deviate from the ones reported here in fields with planting dates or hybrid maturities that differ markedly from the ones used as the basis for the forecasts.