This article summarizes the simulated crop stages and yield forecasts performed on Aug. 16 for 40 locations across the U.S. Corn Belt using the UNL Hybrid-Maize crop model; the data can be seen in Table 1. Details on 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.

During the last two weeks, solar radiation was above the historical average in sites located in NE and KS while below average records were registered in IL and OH. The remaining sites presented near average values. Daily air temperature was well above average in NE, KS and IA, while nighttime temperature was near historical records in the entire Corn Belt. In the case of rainfall, most locations exhibited below-normal records, except for sites in MN and in the central and eastern part of the region (IN, IL, MI and OH) where precipitation was near or above normal. A summary of weather conditions during the last two weeks is shown in Figure 1.

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 Aug. 2 and Aug. 16, 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.

Table 1. Data from simulations of 2022 end-of-season corn yield potential and real-time crop stage performed on Aug. 16.

	Location	Water regime	Long-term average yield (bu/ac) §	Range of Yp forecasts as of Aug 16 (bu/ac)¶ 25th	Range of Yp forecasts as of Aug 16 (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	177	194	12%	82%	6%	R4, Dough
	Beatrice	Dryland	161	111	119	100%	0%	0%	R5, Dent
		Irrigated	230	196	205	84%	16%	0%	R5, Dent
	Clay Center	Dryland	157	78	94	100%	0%	0%	R4, Dough
		Irrigated	245	225	241	20%	80%	0%	R4, Dough
	Concord	Dryland	174	97	118	100%	0%	0%	R4, Dough
		Irrigated	249	229	253	12%	85%	2%	R4, Dough
	Elgin	Irrigated	252	230	250	21%	74%	6%	R4, Dough
	Holdrege	Dryland	113	88	105	68%	32%	0%	R5, Dent
		Irrigated	242	241	258	0%	88%	12%	R4, Dough
	McCook	Dryland	88	35	35	100%	0%	0%	R5, Dent
		Irrigated	225	186	192	100%	0%	0%	R5, Dent
	Mead	Dryland	182	122	143	98%	2%	0%	R4, Dough
		Irrigated	235	205	223	42%	58%	0%	R5, Dent
	North Platte	Dryland	90	46	56	98%	2%	0%	R4, Dough
		Irrigated	234	220	241	8%	90%	2%	R4, Dough
	O'Neill	Irrigated	227	207	226	24%	70%	5%	R4, Dough
IA	Ames	Dryland	229	179	203	79%	21%	0%	R4, Dough
	Crawfordsville	Dryland	230	136	153	100%	0%	0%	R4, Dough
	Lewis	Dryland	209	138	158	96%	4%	0%	R4, Dough
	Nashua	Dryland	228	230	252	3%	70%	27%	R3, Milk
	Sutherland	Dryland	210	142	173	97%	3%	0%	R4, Dough
IL	Bondville	Dryland	235	214	236	17%	80%	3%	R4, Dough
	Freeport	Dryland	212	234	252	0%	25%	75%	R4, Dough
	Olney	Dryland	190	204	212	0%	69%	31%	R5, Dent
	Peoria	Dryland	211	219	236	0%	66%	34%	R4, Dough
	Springfield	Dryland	179	225	234	0%	0%	100%	R4, Dough
IN	Butlerville	Dryland	224	209	219	5%	95%	0%	R4, Dough
	Columbia City	Dryland	224	231	243	0%	79%	21%	R4, Dough
	Davis	Dryland	231	219	236	0%	100%	0%	R4, Dough
	West Lafayette	Dryland	238	202	221	47%	53%	0%	R4, Dough
KS	Garden City	Irrigated	218	178	180	100%	0%	0%	R5, Dent
	Hutchinson	Dryland	100	Black layer on Aug. 2. Final yield: 61 bu/ac					Matured
	Manhattan	Dryland	136	Black layer on Aug. 13. Final yield: 156 bu/ac					Matured
	Scandia	Dryland	131	62	86	100%	0%	0%	R4, Dough
		Irrigated	226	231	249	0%	69%	31%	R4, Dough
	Silverlake	Dryland	141	145	147	0%	100%	0%	R5, Dent
		Irrigated	209	213	218	0%	100%	0%	R5, Dent
MI	Ceresco	Dryland	180	196	221	0%	33%	67%	R2, Blister
MN	Eldred	Dryland	115	101	139	38%	23%	38%	R3, Milk
	Lamberton	Dryland	212	201	223	16%	84%	0%	R4, Dough
	Waseca	Dryland	219	236	265	0%	38%	62%	R3, Milk
MO	Brunswick	Dryland	181	136	177	50%	50%	0%	R4, Dough
	Monroe City	Dryland	174	198	215	0%	10%	90%	R4, Dough
	St. Joseph	Dryland	167	187	212	0%	18%	82%	R4, Dough
ND	Dazey	Dryland	109	90	132	41%	22%	37%	R3, Milk
OH	Custar	Dryland	208	214	235	3%	59%	38%	R3, Milk
	South Charleston	Dryland	216	220	244	0%	66%	34%	R4, Dough
	Wooster	Dryland	210	210	237	3%	59%	38%	R2, Blister

§Long-term (last 20-plus 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 dough stage in a majority of sites, except for those in the northern and eastern fringes of the region. Due to high temperatures, corn has even reached kernel dent stage in the southern fringe of the Corn Belt (KS and southern NE and IL) and black layer at two sites in KS (Figure 2). Locations in the north and eastern fringes of the Corn Belt are behind last year’s corn development due to late planting (see forecasts for Aug. 4, 2021 and Aug. 25, 2021).

Figure 2. Simulated developmental stage for irrigated and rainfed corn at each location. R2: blister; R3: milk; R4: dough; R5: dent; physiological maturity: Matured. Separate maps are shown for irrigated corn (top) and rainfed corn (bottom).

Irrigated Corn: Near or Below-average Yields are Expected

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. Most irrigated sites (seven out of 13) exhibit a high probability (>75%, that is, three out of four chances) of near-average yield potential. Three sites located in southern NE and southwestern KS exhibit a high probability of below-average yield potential. Overall, the forecasted scenario for irrigated maize yield potential in the current season seems similar to the 2021 forecasted yield but 5% lower than the long-term average.

Rainfed Corn: Yield Potential is Highly Variable Across Rainfed Sites

Compared with our previous forecast, below-average rainfall during the past two weeks in most sites in NE, KS and IA increased the probability (>75%, that is, three out of four chances) of below-average yield potential in those states. Overall, 11 sites distributed in NE, KS, and south and west of IA have a high probability of below average yields. In contrast, a high probability of above average yield potential is expected in five scattered sites in the southern fringe of the Corn Belt (KS, MO and southern IL) and north of IL (Figures 3 and 4) because of sufficient rainfall and near-normal temperature. Probability of near-average yield is high at six sites mostly located in the eastern part of the Corn Belt (IN and IL). Overall, the forecasted regional average yield for rainfed maize in 2022 seems similar to that forecasted in 2021 but 7% lower than the long-term average.

Figure 3. Vertical lines indicate the range of forecasted 2022 corn yield potential by Aug. 16 based on average 2022 planting date 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 and the red dots represent the forecasted 2022 corn yield potential at sites that have already reached maturity. 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 already reached the dough stage in most parts of the Corn Belt, while dent stage (or even black-layer) has been reached in a few sites in the southern fringe of the region. Compared to our previous forecasts, there is a higher probability of below-average yields for both irrigated and rainfed corn, especially in the western fringe in the region. Overall, the regional average yield is expected to be 5% (irrigated corn) and 7% (rainfed corn) below the historical averages, which differs from USDA yield forecasts that predict 2022 corn yield to be similar to the average during the 2015-2021 period.

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 those reported here in fields with planting dates or hybrid maturities that differ markedly from those used as the basis for these forecasts. We will follow up with the final forecasted yield and analysis of the 2022 crop season in September.