Simulations of 2022 end-of-season corn yield potential and real-time crop stage were performed on Aug. 2 for 40 locations across the U.S. Corn Belt using the UNL Hybrid-Maize crop model in collaboration with faculty and extension educators from 10 universities. This article summarizes the simulated crop stages and yield forecasts; the data can be seen in Table 1. Details on the UNL Hybrid-Maize crop model and the underpinning methodology to simulate phenology and forecast end-of-season yields, as well as on interpretation and uses of yield forecasts, are described in a previous article.

Over the past two weeks, average air temperature has remained near average values in most of the Corn Belt. However, a few sites in southern KS and most of NE showed daily temperatures above historical average and the eastern fringe of the region (IN and OH) has also experienced above-average night temperatures. In the case of rainfall, areas in eastern NE, southwestern MN, the entire IA, and central IL exhibited below normal records, while sites in the southeastern fringe of the Corn Belt experienced above-normal rainfall. The remaining locations across the region showed near-normal records. A summary of weather conditions during the last two weeks is shown in Figure 1.

Simulated Corn Stage Across 40 Locations

Corn has reached kernel milk stage in the south and western fringes of Corn Belt, while sites in ND and the eastern area are still in silking stage. Corn in KS and southern NE are ahead of the rest of the locations, reaching the dough and even dent stage (Figure 2). Except for NE and KS, most locations are behind last year’s corn development by early August, especially in ND, due to late planting.

Irrigated Corn: High Probability of Near-average Yields

The range of forecasted irrigated corn yield potential for each location, as well as the probabilities for yields above, near, or below average, are shown in Figures 3 and 4. Five out of 13 sites exhibit a high probability (>75%, that is, a chance of 3 out of 4) of near-average yield potential. Favorable weather during the rest of the season that results in a long grain-filling period may increase the likelihood of above-average yield. The chance of below-average yield is low across irrigated sites in north and central NE and eastern KS but increases in a few sites in south NE and southwestern KS. At this point, the forecasted scenario for irrigated maize in the current season seems similar to the 2021 forecasts.

Variable 2022 Forecasted Corn Yield Across Rainfed Locations

Forecasted yield potential is highly variable across the 35 rainfed sites (Figures 3 and 4). There is a high probability of above-average yield (>75%) at four sites in the south-central area of the Corn Belt, while five sites distributed across IA, NE and southern KS have a high probability of below-average yields. Probability of near-average yield is relatively high in the central and eastern part of the Corn Belt (most of IL, IN and OH).

Compared with our previous forecast, below-average rainfall in IA and eastern NE during the past two weeks increased the probability of below-average yields in that area, reducing the forecasted yield for the 2022 season. Compared with the 2021 forecast, the forecasted scenario for rainfed maize seems more favorable in ND, MN, NE and north of KS in the current season, while the scenario looks more pessimistic in most sites of IA and southern KS. In the remaining area, the scenario looks similar compared with 2021 forecasts. Overall, the forecasted yield for the entire Corn Belt is near the historical average.

Conclusions

Similar to our previous forecast in mid-July, there is a high probability of near-average yields for most of the irrigated sites.

For rainfed corn, the scenario is diverse across regions. Most sites in the central and eastern part of the Corn Belt have a high probability of near-average yields. Above-average yield is expected at four locations located in the southern fringe of the Corn Belt. In contrast, five sites in IA, NE, and southern KS exhibit a high probability of below-average yields. Temperature and rainfall during August will likely define the trend for all sites across the region.

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 that 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 those used as the basis for the forecasts. We will follow up with further forecasts in late August.