Large Variations in Minnesota Corn Yield Estimates

September 5, 2016


Most crop experts are now agreeing that Minnesota’s 2016 crop yields are likely to be highly variable across the State, especially for corn yields. In the last USDA Crop Report on August 12, the 2016 Minnesota corn yield was projected at 184 bushels per acre, which would be the second highest ever, trailing only last year’s record yield of 188 bushels per acre. Other recent statewide average corn yields are 158 bushels per acre in 2014, 160 bushels per acre in 2013, 165 bushels per acre in 2012, and 156 bushels per acre in 2011.

Interestingly, there has been quite a range in the estimated 2016 Minnesota corn yields by private analysts, ranging from about 172 to near 180 bushels per acre; however, all of the estimates are below the August USDA estimate, but are still well above final statewide averages from 2011-2014. Historically, Minnesota final average corn yields tend to decline a bit as harvest goes on, due to average corn yields in Central and Northern being lower than anticipated. 2016 may be somewhat different than other years, as portions of Southwest and South Central Minnesota also experienced a variety of weather challenges during the growing season, and are also likely to have lower yield levels than anticipated.

The USDA Crop Report on August 12 projected Iowa to achieve a record average corn yield of 197 bushels per acre in 2016, which would surpass the 2015 State record yield of 192 bushels per acre. Most private analysts agree that Iowa’s 2016 corn crop should surpass, or be close, to the 2015 record yield; however, some late season dry weather concerns in portions of the State, along with a higher than normal disease incidence, has raised some concerns regarding Iowa’s high corn yield projections. Statewide corn yields in States such as Illinois, Indiana, and Ohio have been “up and down” in recent years. After achieving record or near-record yields in 2014, corn yields dropped off considerably in 2015. For 2016, Illinois corn yields are projected to approach the 2014 record level, Indiana yields are estimated to be above average, and Ohio yields are expected to be slightly below average.

In the August 12 Report, USDA projected a record national average corn yield of 175.1 bushels per acre, which would surpass the previous record U.S. corn yield of 171 bushels per acre in 2014. USDA is currently estimating total 2016 U.S. corn production at over 15.1 billion bushels, which would be the highest in history, and would well surpass the previous record U.S. corn production of 14.2 billion bushels in 2014. Many private analysts feel that the USDA estimates for both the national average corn yield and total 2016 U.S. corn production are a bit too high, given the poor early and mid-season growing conditions in the Western Corn Belt, along with numerous areas that have faced crop challenges later in the growing season.

One of the biggest challenges with the Minnesota corn crop is usually getting the crop mature before the first killing frost. Average first frost dates range from around September 20 in the northern areas of the State to around October 15 in Southeast Minnesota. The good news is that crop development in many areas of the State are much more advanced in the 2016 crop year, as compared to a normal year. As of August 31, a total of 2,336 growing degree units (GDU’s) had been accumulated since May 1, 2016, at the University of Minnesota Southern Research and Outreach Center at Waseca, MN. That level of GDU accumulation is approximately 10 percent above normal, and usually does not occur until September 13 in an average year.

Corn is considered to have reached physiological maturity once it is in the “black layer” stage. Some of the earlier planted corn in Southern Minnesota is likely to reach this stage by September 10-15, while later planted corn, and corn in other areas of the State, may be a week or two later. The concern for an early frost does not appear to be as great in 2016, as compared to years such as 2014 and 2013, when corn was planted much later than this year, and growing conditions were much less favorable.

Many portions of Minnesota have received record. or near-record, levels of precipitation during the 2016 growing season. The U of M Research Center at Waseca received 11.7 inches of rainfall in August, which was the second wettest August in history, and was just shy of the record monthly rainfall in 1924. The very wet August followed the second wettest July in history at Waseca, with 8.93 inches of rainfall recorded. This brought the two-month total precipitation for July and August at Waseca to 20.63 inches, which exceeded the previous two-month precipitation record at Waseca by over 3 inches, which was set in 1979. Most long-time farm operators remember the very wet growing season of 1993. There was over 5 inches less rainfall at Waseca in the July and August period that year, as compared to 2016.

One concern for harvest of this year’s corn and soybean crop, as well as other crops, could be the extremely wet field conditions that exist in many areas of Minnesota and surrounding States. If the wetter than normal conditions continue through September, the saturated field conditions could lead to some very challenging harvest conditions in some areas. These type of soil conditions are also very favorable for the development of root rot and stalk rot diseases in crops, which could result in more crop lodging, as well as increased harvest losses, in some areas.

The August 12 USDA Crop Report was based on crop conditions as of August 1, and the next Crop Report on September 12 will be based on conditions as of September 1. Many crop experts expect USDA to adjust the 2016 U.S. average corn yield estimate, as well  as overall 2016 production levels, slightly lower in the September 12 Crop Report. This would be more in line with where many crop experts are projecting U.S. corn yields in 2016.


Note — For additional information contact Kent Thiesse, Farm Management Analyst and

Vice President, MinnStar Bank, Lake Crystal, MN.  (Phone — (507) 381-7960);

E-mail —


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