Simulations of 2022 end-of-season corn yield potential and real-time crop stage were performed on July 19 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 found 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.

A summary of weather conditions during the last 60 days (from May 19 to July 18) is shown in Figure 1. The season started with warm conditions throughout a large portion of the Corn Belt, showing average temperatures above normal in most sites in NE, IA, IL, IN, OH and southern KS and MN. In northern areas (ND, MI and north of IL, MN and IN), as well as in MO and northern KS, temperature was near the historical average. In addition, most of the western and northwestern regions (NE, IA, MN and ND) exhibited below normal rainfall. Remaining sites showed near normal rainfall, except for OH and a few scattered locations in IL, IN and MO with rainfall above normal.

Simulated Corn Stage Across 40 Locations

Corn has reached silking in the southern fringe of the Corn Belt, including NE, KS, MO, most sites in IL, and southeast of IA and IN. In contrast, sites in the northern and eastern fringes of the region are still in vegetative phases (ND, MN, most of IA, northern IL, IN, MI and OH) (Figure 2). Due to the later planting date this season, most locations in these northern and eastern sites are running behind last year’s corn development.

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. Although it is still too early in the season, there is a relatively high probability of near-average yields for all sites. Weather conditions during the rest of the growing season will determine if most irrigated sites will have near-average yield potential.

Variable 2022 Forecasted Corn Yield Across Rainfed Locations

Forecasted yield potential is highly variable across rainfed sites (Figures 3 and 4). At this point of the season, probability of near-average yield is relatively high in IA, MN and towards the eastern fringe of the Corn Belt (IL, IN and OH). In contrast, below-average yields probability increases in IA, NE and KS due to a combination of high temperature, which increases crop water requirements, and low rainfall, with larger negative impact on yield at sites without presence of shallow water tables during the growing season. However, current yield forecasts are highly uncertain and may change depending on precipitation and temperature during the rest of July and August. There is a high probability of below-average yield (>75%) only at three sites (southeast IA, southwest NE and southern KS), while there are only two sites where probability of above-average yield is high (northwest MO and southcentral IL).

Conclusions

Corn has reached silk stage in the west and southern fringes of the Corn Belt, while it is still in vegetative stages throughout the north, eastern and most of central parts of the region. Although it is still too early to make strong inferences about end-of-season yields for irrigated corn, there is a relatively high probability for near-average yields for a majority of sites, but this can change depending upon temperature during the next four weeks.

For rainfed corn, the scenario is diverse across regions, with higher probability of near-average yields in the eastern fringe of the region and below-average yields in the western area due to a combination of below average rainfall and high daytime temperature during the past two months. Temperature and rainfall during the rest of July and early 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 early August.