2012 Corn Yield Potential Forecast Based on Aug. 27 Hybrid-Maize Simulation - August 30, 2012
August 30, 2012
Irrigated corn yield potential is predicted to be 2-8% below long-term average, while dryland yield potential in much of the Corn Belt will be moderately to severely reduced, falling 22-67% below normal.
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To evaluate the impact on potential production at 12 sites across the Corn Belt (Figure 1), we used the Hybrid-Maize model to estimate end-of-season yield potential based on actual weather up to August 27, and historical long-term weather data to complete the season using data from each of the past 30 years. This approach gives a “real-time,” in-season estimate of expected yield potential (the median value shown in Table 1), and the most probable range (25th to 75th percentiles) depending on weather conditions from August 27 until the corn crop reaches maturity (see Applying the Hybrid-Maize Predictions, below).
Simulations were run for dryland corn in Iowa, Illinois, and South Dakota, and for both irrigated and dryland corn in Nebraska. Simulations were based on the typical planting date, hybrid relative maturity, plant population, and soil properties at each location. Underpinning data used in these simulations are provided in Table 1. (Also see Applying ... for how to interpret simulations shown in Table 1.)
August 27 projections give a narrower range than our projections based on August 13 simulations, and, at some locations the crop reached blacklayer during the past week (Mead, Concord, O’Neill, and Nashua, Iowa). Projected yield potential since August 13 has not changed by more than 7% across all locations, except for the two locations in west central Illinois (Monmouth) and south central Illinois (Bondville) where predicted dryland yield has increased by 30% due to good rains and cooler weather. It should be noted, however, that if unusually hot, dry weather occurred during pollination at these Illinois locations, such a large yield improvement would not be expected due to reduced seed set. Still, projections of final yield potential are below the long-term average at all sites, under both irrigated and dryland conditions (Table 1).
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There is a modest yield loss (5-8%) for locations in South Dakota (Brookings) and west central and north central Illinois (Monmouth and DeKalb) while a moderate yield loss of 22-28% is predicted for dryland corn in central and northeast Iowa (Gilbert and Nashua). Severe yield loss of 32-67% is projected for dryland corn in south central, eastern, and northeastern Nebraska (Clay Center, Mead, and Concord), northwest Iowa (Sutherland), and south central Illinois (Bondville) (Table 1). In contrast to large loss of yield potential in these dryland systems, the projected losses in yield potential at all irrigated sites are modest at about 2-3% in south central Nebraska (Clay Center, Holdrege), and 7-8% in east and northeast Nebraska (O’Neill, Concord, and Mead) (Table 1). Projected irrigated yield potential since August 13 has increased by about 3% due to cooler weather during the past two weeks.
The bottom line is that 2012 irrigated yields will be moderately lower than the long-term averages (2-8% below normal), while dryland corn yield potential in much of the Corn Belt will be moderately to severely reduced (22-67% below normal). It is important to keep in mind that yields can be even lower at places where both prolonged drought and high temperature stress at pollination have occurred. Also, greater field-scale variability is being observed this year in irrigated fields due to the inability of some irrigation systems to keep up with crop water use demand, problems with pivot irrigation nozzles and uneven watering, and additional stresses from insects and diseases. Such problems can contribute to reduced yields at irrigated sites of more than the 2-8% simulated by the model.
Patricio Grassini, Research Associate Professor, Agronomy and Horticulture Department
Jenny Rees, UNL Extension Educator
Haishun Yang, Associate Professor, Agronomy and Horticulture Department
Kenneth G Cassman, Professor, Agronomy and Horticulture Department
Table 1. 2012 In-season yield potential forecasts as of August 17 using UNL Hybrid-Maize Model | |||||||||
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Location, State | Water Regime |
Soil Type¶ & Initial Water |
Plant Pop.¶ (ac-1) |
Relative Maturity (days) |
Planting Date¶ |
Long-term Yp (bu/ac)‡ |
2012 Forecasted Yp (bu/ac) | ||
75th* | Median | 25th** | |||||||
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Holdrege, NE | Irrigated | Silt loam | 32.4k | 113 | April 27 |
248 |
246 |
243 |
237 |
Clay Center, NE |
Irrigated Rainfed |
Silt clay loam 100% ASW |
32.4k 24.0k |
113 |
April 23 April 23 |
250 146 |
246 99 |
242 98 |
242 97 |
Mead, NE |
Irrigated Rainfed |
Silt clay loam 100% ASW |
32.4k 28.0k |
113 | April 30 |
240 160 |
— |
224 53 |
— |
Concord, NE |
Irrigated Rainfed |
Silt loam 100% ASW |
32.4k 29.0k |
104 | May 3 |
235 154 |
— |
218 90 |
— |
O’Neill, NE | Irrigated |
Sandy loam 100% ASW |
32.4k | 106 | May 3 |
225 |
— | 207 | — |
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Brookings, SD | Rainfed |
Silt clay loam 100% ASW |
30.0k | 98 | May 4 |
120 |
116 | 110 | 105 |
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Sutherland, IA | Rainfed |
Silt clay loam 100% ASW |
31.4k | 99 | May 1 |
168 |
105 |
104 | 102 |
Gilbert, IA | Rainfed |
Loam 100% ASW |
32.4k | 110 | April 26 |
200 |
153 | 145 | 141 |
Nashua, IA | Rainfed |
Loam 100% ASW |
32.4k | 99 | May 1 |
198 |
— | 155 | — |
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Monmouth, IL | Rainfed |
Silt loam 100% ASW |
32.4k | 112 | April 27 |
212 |
193 | 189 | 183 |
DeKalb, IL | Rainfed |
Silt clay loam 100% ASW |
32.4k | 111 | May 1 |
201 |
208 | 190 | 177 |
Bondville, IL | Rainfed |
Silt clay loam 100% ASW |
32.4k | 114 | April 20 |
197 |
135 | 134 | 131 |
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¶ Simulations based on dominant soil series, average planting date, and plant population (PP) and relative maturity (RM) of most widespread hybrid at each location (Grassini et al., 2009). ‡ Average (20+ years) simulated yield potential (Yp). * 75th and ** 25th percentile yields, which represent favorable and unfavorable weather scenarios for the rest of the season, respectively. |
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