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.

Figure 1. Daily solar radiation, maximum and minimum air temperature (Tmax and Tmin), total rainfall, and total reference grass-based evapotranspiration (ET) for the time period between May 19 and July 18, 2022. Vertical bars indicate the range for these variables based on 20-plus years of weather records. The horizontal thick line indicates the long-term average, and the red dots indicate the 2022 values for the same period.

Table 1. Data from simulations of 2022 end-of-season corn yield potential and real-time crop stage performed on July 19.

	Location	Water regime	Long-term average yield (bu/ac) §	Range of Yp forecasts as of Jul 19 (bu/ac)¶ 25th	Range of Yp forecasts as of Jul 19 (bu/ac)¶ 75th	Probability (%) of 2022 yield to be: Below (relative to the long-term Yp)†	Probability (%) of 2022 yield to be: Near (relative to the long-term Yp)†	Probability (%) of 2022 yield to be: Above (relative to the long-term Yp)†	Simulated current crop stage*
NE	Alliance	Irrigated	193	193	221	0%	55%	45%	V14
	Beatrice	Dryland	161	158	179	22%	50%	28%	R2, Blister
		Irrigated	230	198	223	47%	47%	6%	R2, Blister
	Clay Center	Dryland	157	86	142	72%	28%	0%	R2, Blister
		Irrigated	245	223	241	22%	72%	5%	R2, Blister
	Concord	Dryland	174	117	179	58%	28%	15%	R1, Silking
		Irrigated	249	229	263	20%	65%	15%	R1, Silking
	Elgin	Irrigated	252	236	266	15%	74%	12%	R1, Silking
	Holdrege	Dryland	113	83	128	41%	24%	35%	R2, Blister
		Irrigated	242	229	257	15%	68%	18%	R1, Silking
	McCook	Dryland	88	38	79	75%	22%	2%	R2, Blister
		Irrigated	225	196	222	30%	60%	10%	R2, Blister
	Mead	Dryland	182	138	182	52%	42%	5%	R1, Silking
		Irrigated	235	210	233	32%	60%	8%	R2, Blister
	North Platte	Dryland	90	45	101	60%	12%	28%	R1, Silking
		Irrigated	234	227	254	8%	72%	20%	R1, Silking
	O'Neill	Irrigated	227	210	244	19%	62%	19%	R1, Silking
IA	Ames	Dryland	229	200	239	32%	53%	15%	V16
	Crawfordsville	Dryland	230	166	191	84%	16%	0%	R1, Silking
	Lewis	Dryland	209	175	223	42%	33%	25%	V18
	Nashua	Dryland	228	223	249	9%	67%	24%	V14
	Sutherland	Dryland	210	178	210	42%	48%	9%	V16
IL	Bondville	Dryland	235	205	239	33%	57%	10%	R1, Silking
	Freeport	Dryland	212	201	251	16%	47%	38%	V16
	Olney	Dryland	190	197	223	0%	44%	56%	R2, Blister
	Peoria	Dryland	211	187	216	34%	52%	14%	R1, Silking
	Springfield	Dryland	179	212	237	0%	14%	86%	R1, Silking
IN	Butlerville	Dryland	224	202	227	26%	68%	5%	R1, Silking
	Columbia City	Dryland	224	219	241	0%	79%	21%	V16
	Davis	Dryland	231	225	246	0%	89%	11%	V18
	West Lafayette	Dryland	238	201	226	53%	47%	0%	V18
KS	Garden City	Irrigated	218	193	219	33%	61%	6%	R3, Milk
	Hutchinson	Dryland	100	51	69	97%	3%	0%	R4, Dough
	Manhattan	Dryland	136	145	168	3%	38%	59%	R3, Milk
	Scandia	Dryland	131	75	138	64%	17%	19%	R1, Silking
		Irrigated	226	210	250	6%	64%	31%	R1, Silking
	Silverlake	Dryland	141	124	170	28%	33%	39%	R3, Milk
		Irrigated	209	196	230	19%	56%	25%	R3, Milk
MI	Ceresco	Dryland	180	174	221	5%	33%	62%	V10
MN	Eldred	Dryland	115	108	148	23%	15%	62%	V10
	Lamberton	Dryland	212	194	229	16%	68%	16%	V16
	Waseca	Dryland	219	205	250	19%	43%	38%	V14
MO	Brunswick	Dryland	181	169	202	23%	41%	36%	R1, Silking
	Monroe City	Dryland	174	177	221	14%	24%	62%	R1, Silking
	St. Joseph	Dryland	167	188	218	5%	14%	82%	R1, Silking
ND	Dazey	Dryland	109	118	162	7%	22%	70%	V8
OH	Custar	Dryland	208	199	230	11%	57%	32%	V12
	South Charleston	Dryland	216	220	261	3%	44%	53%	V16
	Wooster	Dryland	210	192	229	19%	62%	19%	V10

§Long-term (last 20+ years) potential yield at each location and surrounding area.
¶ Range of forecasted 2022 potential yields based on average planting date in 2022, indicating the potential yields in the 25th and 75th percentile of the potential yield distribution (associated with respective adverse and favorable weather scenarios during the rest of the season).
† Probability of obtaining a 2022 yield below (10%) than the long-term potential yield at each location.

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.

Figure 2. Simulated developmental stage for irrigated and rainfed corn at each location. Vn: vegetative stage (nth leaf); R1: silking; R2: blister; R3: milk; R4: dough. Separate maps are shown for irrigated corn (top) and rainfed corn (bottom).

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).

Figure 3. Vertical lines indicate the range of forecasted 2022 corn yield potential by July 19 based on average planting date in 2022 at each location. Horizontal lines indicate the 25th and 75th percentiles of the yield distribution (associated with respective adverse and favorable weather scenarios during the rest of the season). The blue squares indicate the long-term (2005-2021) average yield potential at each location. Separate charts are shown for irrigated corn (top) and rainfed corn (bottom).

Figure 4. Probability of the 2022 yield potential to be below (10%, green color) the long-term (2005-2021) average yield potential at each location. Separate maps are shown for irrigated corn (top) and rainfed corn (bottom). The larger a color section is within the pie chart, the higher the probability that end-of-season corn yield will be in that category.

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.