Focus on ag: 2021 crop yield expectations highly variable

Kent Thiesse
Farm Management Analyst and Vice President, MinnStar Bank
Kent Thiesse

August is typically the month of the year when the first producer survey yield estimates from the U.S. Department of Agriculture are released, as well as yield projections from major private forms.

This yield data is gathered in a number of formats, including producer surveys, crop tours and satellite technology. There is not necessarily a method that has proven more accurate than any other, as all methods have some strengths as well as some limitations. The one consistency being echoed by most crop experts is that the 2021 crop yields are likely to be highly variable and are very difficult to predict, especially in drought-impacted areas of Minnesota, western Iowa, North Dakota and South Dakota.

Most of the crop information in these estimates was based on crop conditions in early-to-mid August, so any major changes in conditions after that timeframe could alter final state or national yield numbers.

The statewide and national corn and soybean yield estimates in the USDA crop report that was released on Aug. 12 were based on crop conditions as of Aug. 1. The USDA report was based on a survey of 18,600 crop producers from across the United States that was conducted by the National Agricultural Statistics Service.

The next USDA crop report will be released on Sept. 10 and will be based on crop conditions as of Sept. 1. This report will include actual field survey data in the yield and production estimates.

Three of the main private firms that release crop yield and production estimates during August all use different technology to arrive at their projections. The “Pro Farmer Crop Tour” is quite well established and has been around for several decades. Pro Farmer Tour gathers field yield data from the primary corn and soybean production areas in seven states during the third week of August, which is then adjusted for crop maturity and historical differences between tour data and final yield numbers.

Yield adjustments are also made in states that have unique conditions in certain areas of a state, such as drought conditions in Minnesota and South Dakota during 2021 or the derecho storm that swept across Iowa in 2020.

Another well established estimate of corn and soybean yields on an annual basis is the “National Producer Yield Survey” that is conducted annually by Allendale, Inc. The survey data was received from Aug. 16-27 from corn and soybean producers in 31 states, which allowed Allendale to make corn and soybean yield projections for 12 states in addition to the national yield estimates.

DTN partners with the GroIntelligence (GroIntel) firm to conduct a “digital yield tour” of the primary corn and soybean production areas in the United States. DTN derived their yield estimates from GroIntel, utilizing satellite imagery taken in early August, which are then adjusted based on actual rainfall amounts and temperature data, as well as for the drought index.

Nationally, corn yield estimates included Pro Farmer at 177 bushels per acre, Allendale at 176.2 bushels per acre and DTN GroIntel at 176.5 bushels per acre. Comparatively, the NASS yield estimate in the Aug. 12 USDA crop report was 174.6 bushel per acre.

The Pro Farmer national corn yield projection for 2021 would surpass the previous record average U.S. corn yield of 176.6 bushels per acre in 2017. The current Allendale and DTN GroIntel corn yield estimates are also quite close to the record national average corn yield. The 2021 national corn yield projections compare to final average U.S. corn yields of 172 bushels per acre in 2020, 167.4 bushels per acre in 2019, and 176.4 bushels per acre in 2018.

While the national yield differences between the USDA corn yield estimate (174.2 bushels per acre) and the Pro Farmer projection (177 bushels per acre) may not seem that significant, they potentially represent a large difference in the final total U.S. corn production level for 2021, which could impact grain market prices in the coming months.

The current difference between the USDA national corn yield estimate and the Pro Farmer estimate is 2.5 bushels per acre. Based on the USDA estimate of 84.5 million harvested acres of corn in the U.S. in 2021, that yield difference represents over 210 million bushels of corn.

Generally, the state-by-state average corn yield estimates released by USDA in the Aug. 12 crop report were slightly lower that the yield projections released from the other crop tours and surveys.

For example, USDA estimated Minnesota’s 2021 crop yield at 166 bushels per acre, compared to yield estimates of 170 by Pro Farmer, 171 by Allendale and nearly 181 by DTN GroIntel. There were also large variations in corn yield projections for North Dakota, South Dakota and Wisconsin.

Obviously, the severe drought conditions in portions of these states make corn yields very difficult to predict. Corn yield projections for the current growing season were much more consistent in states such as Iowa, Illinois, Indiana and Nebraska.   

NASS estimated the U.S. national average soybean yield at 50 bushels per acre in the Aug. 12 USDA crop report. This compares to national soybean yield estimates of 51.2 bushels per acre by Pro Farmer, 50.1 bushels per acre by Allendale, and 51.5 bushels per acre by DTN GroIntel.

All of these yield estimates would be below the record national average soybean yield of 52 bushels per acre in 2016. Overall, the various state-by-state soybean yield projections appeared to be a bit more consistent than the corn estimates were. Once again, the widest variation in soybean yield projections occurred in the states that have incurred the greatest impact from drought conditions during the 2021 growing season.

Based on the Aug. 23 USDA crop progress report, 60% of the corn crop in the U.S. rated good-to-excellent, which is below average for mid-August in recent years.

The higher crop ratings for corn dropped by 2% from the crop report issued a week earlier on Aug. 16. The 2021 corn ratings compare to a good-to-excellent crop rating of 64% in late August a year ago. The highest statewide good-to-excellent ratings were Wisconsin at 75%, Indiana at 71%, Ohio at 69%, and both Illinois and Nebraska at 67%.

The lowest good-to-excellent corn ratings were in North Dakota at 16%, South Dakota at 25% and Minnesota at 34%. Iowa was at 58% in the higher category. North Dakota had 48% of the corn acres listed as poor-to-very poor, with South Dakota having 39% in the lower categories.

The weekly USDA crop ratings on Aug. 23 listed 56% of the U.S. soybean crop as good-to-excellent, which was down from 58% a week earlier on Aug. 16. A year ago, 69% of the U.S. soybean crop was rated good-to-excellent in late August.

Once again, the eastern Corn Belt lead the way regarding the percent of soybean acreage in the higher categories with Indiana at 77%, Ohio at 73%, and Illinois at 67%. Other states with a high percentage of soybeans in the good-to-excellent category included Wisconsin at 75%, Nebraska at 69% and Iowa at 61%.

The lowest good-to-excellent ratings were North Dakota at 12% South Dakota at 35% and Minnesota at 31%.

Many crop advisors point out that the 2021 national and statewide average corn and soybean yields are very hard to predict, due to the wide variability in crop conditions across the region.

Many of the areas that have been hard-hit by drought conditions during of the growing season have finally started getting more frequent rainfall events during the last half of August. It will be interesting to see how much the added rainfall helps stabilize the yield deterioration in areas that had more moderate drought conditions.

The final crop yields in these areas will likely determine if the final statewide yields in states like Minnesota, North Dakota and South Dakota end up closer to the USDA corn and soybean yield estimates or if the final figures are closer to the higher yield projections by the private firms that released yield estimates.

For additional information contact Kent Thiesse, farm management analyst and senior vice president, MinnStar Bank, Lake Crystal, Minn., at (507) 381-7960 or, or visit