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Recent rainfall, along with some widespread severe storms, could alter the crop expectations in some locations.

Kent Thiesse, Farm management analyst and vice president

September 8, 2021

7 Min Read
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Most crop experts agree that 2021 corn and soybean 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 the yield estimates released by USDA and by private companies was based on crop conditions in early to mid-August, so any major changes in conditions after that timeframe could alter the future yield projections.

Fairly widespread and significant rainfall was received in many areas of the Upper Midwest during the last 10 days of August, including in some of the extremely dry areas of Southwest and West Central Minnesota, Northwest Iowa and Eastern South Dakota. Other areas in North Dakota, Montana, Western and Central South Dakota, and Northwest and North Central Minnesota received less rainfall and crop stress continues to worsen. Most of the eastern Corn Belt had adequate moisture, so there was very little impact from the added rainfall.

In some of the locations with severe drought stress, the recent rainfall may have been too late to have much impact on the 2021 corn and soybean crop; however, in areas with more moderate impacts from drought conditions there will likely still be some benefit from the rainfall. If corn and soybeans that had not reached maturity and were still in viable condition, the improved conditions should help stabilize or even enhance final yield potential. The final impacts of the late August rainfall will probably not be known until the crop is harvested.

The expanding drought area during late July and early August dimmed the hopes for record yields in many of the major corn- and soybean-producing areas of the United States. Most experts, as well as USDA, expect the final 2021 U.S. corn yield to surpass the final 2020 yield but be shy of a record yield. The final 2021 U.S. soybean yield is expected to end up close to the 2020 yield. The National Ag Statistics Service Crop Report released by USDA on Aug. 12, 2021, estimated the average corn yield at 174.6 bushels per acre, compared to a final U.S. average yield of 172 bushels per acre last year. USDA projected the 2021 average soybean yield at 50 bushels per acre on Aug. 12, compared to a final U.S. soybean yield of 50.2 bushels per acre in 2020.

Storm damage impact on yield

Several severe storms with strong winds and large hail occurred from August 24 to 28 across a widespread area in southern and western Minnesota, eastern South Dakota and Nebraska, Iowa and northern Illinois. Cumulatively, these storms damaged hundreds of thousands of crop acres in the Upper Midwest and caused some property damage on farm sites. The storms were not as severe or widespread as the derecho storm that hit central Iowa and the surrounding states in mid-August 2020; however, the crop damage to corn from this year’s storms was quite similar. Thousands of acres of corn in locations across the Upper Midwest were either laid down flat or snapped off below the ear.

If corn stalks were snapped off below the ear by strong winds, there is not much recourse for producers. It would be very difficult to pick up those ears off the ground to be harvested. Possibly there may be a way to salvage some of the damaged corn for forage to be fed to cattle or the fence off the area and have cattle graze the corn. If the corn was laid flat and the stalk has not been severed, the corn plant should continue to take up nutrients and the corn should mature. Harvesting the corn will be very difficult and may require combining the corn very slowly in one direction. Corn harvest may also require adding special attachments to the corn head being used for harvest. This can add more time and expense to the harvest process and having to run the corn head very close to the ground for harvest can also lead to more damage to equipment. Soybeans that were damaged by the wind may also be twisted and mangled; however, soybean harvest should be a bit easier to manage than corn harvest following severe wind damage.

Whether corn, soybeans or other crops were damaged by wind, hail, or drought, it is important for farmers to contact their crop insurance agent prior to harvesting the crop or before salving the crop for livestock forage. Crop insurance adjusters will do a preliminary evaluation of crop loss but may not be able to finalize the crop loss until after harvest is completed. Some crop producers also carry special wind or hail insurance on their crops and again should contact their insurance agent before beginning to harvest or salvage the crop. At this point, no Federal disaster assistance program has been announced for 2021 crop losses from drought or severe storms. The Wildfire, Hurricane Indemnity Program (WHIP+) did cover a portion of crop losses from late planting, heavy rainfall and other natural disasters for both the 2018 and 2019 crop years.

Fall crop challenges

Normally, one of the biggest challenges with the corn crop in Minnesota and other northern Corn Belt states is usually getting the crop mature before the first killing frost. Average first frost dates range from around Sept. 20 in the northern areas of the region to around Oct. 10-15 in southern Minnesota and northern Iowa. The good news is that crop development in most areas of the region are much more advanced in 2021, as compared to a normal year. Since May 1, the accumulation of growing degree units (GDUs) has been running 8-10 percent or more above normal at most locations, which together with the very dry weather conditions in early August in many areas, has greatly enhanced late-season crop development. 

Corn is considered safe from a killing frost once the corn reaches physiological maturity, which is when the corn kernel reaches the black layer stage. Much of the 2021 corn crop is likely to reach this stage by mid-September, which should greatly reduce any concern for an early frost this year. When the corn reaches black layer, it is still usually at a kernel moisture of 28-32 percent. Ideally corn should be at 15-16 percent kernel moisture for safe storage in a grain bin until next spring or summer. Once the corn reaches maturity, favorable early fall weather can greatly assist with natural dry down of the corn in the field, which can reduce corn drying costs and enhance corn quality. It is likely that a high percentage of the 2021 corn crop will be stored in farm grain storage until the spring and summer of 2022.

Based on the Aug. 30 USDA Crop Progress Report, 60 percent of the corn crop in the U.S. rated good to excellent, which is the same as a week earlier. The 2021 corn ratings compare to a “good-to-excellent” crop rating of 62 percent at the end of August a year ago. The highest statewide good-to-excellent ratings were Wisconsin at 78 percent, Illinois at 70 percent, Indiana at 69 percent and both Ohio and Nebraska at 67 percent. The lowest good-to-excellent corn ratings were in North Dakota at 16 percent, South Dakota at 23 percent and Minnesota at 36 percent. Iowa was at 58 percent in the higher category. Nationwide, 14 percent of the corn crop was listed as poor to very poor, including 47 percent in North Dakota, 45 percent in South Dakota and 27 percent in Minnesota. The combined corn acreage of North and South Dakota is only topped by total statewide corn acreage in Iowa and Illinois.

The weekly USDA crop ratings on Aug. 30 listed 56 percent of the U.S. soybean crop as good to excellent, which was the same as the Aug. 23 weekly report. A year ago, 66 percent of the U.S. soybean crop was rated good to excellent at the end of August. Once again, the eastern Corn Belt lead the way regarding the percent of soybean acreage in the higher categories with Illinois at 71 percent, Ohio at 68 percent and Indiana at 66 percent. Other s

states with a high percentage of soybeans in the good-to-excellent category included Wisconsin at 75 percent, Nebraska at 69 percent and Iowa at 60 percent. The lowest good-to-excellent ratings were North Dakota at 15 percent, South Dakota at 22 percent and Minnesota at 31 percent. Nationally, 15 percent of the soybean crop was listed as poor-to-very poor, including 45 percent in North Dakota, 42 percent in South Dakota and 27 percent in Minnesota. North Dakota ranks fourth in the U.S. in 2021 soybean acreage.

About the Author(s)

Kent Thiesse

Farm management analyst and vice president, MinnStar Bank

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