Focus on Ag: 2019 crop yields remain a big question

Kent Thiesse
Farm Management Analyst and Vice President, MinnStar Bank

In many areas of the Corn Belt, one of the biggest remaining challenges with the corn and soybean crop in 2019 will be getting the crop mature before the first killing frost. Average first frost dates range from around September 20 in the northern areas of the Minnesota, to around October 15 in Southeast Minnesota and Eastern Iowa. Many portions of Minnesota and surrounding States may have some serious challenges this year for the crops to reach maturity before the first killing frost.

As of August 26, a total of 1,938 growing degree units (GDU’s) had been accumulated at the University of Minnesota Southwest Research and Outreach Center at Lamberton, Minn., since May 1, 2019. This level of GDU accumulation from May 1 until late August is about 6 percent below normal and is more than 350 GDU’s behind the 2018 GDU level in late August. When the fact that much of the corn and soybean crop in southwest Minnesota, northwest Iowa and eastern South Dakota was planted 2-3 weeks later than normal is also considered, the low level of GDU accumulation creates some major concerns with crop development and maturity.

As of August 26, it is estimated that less than one-third of the corn crop in Minnesota and the surrounding states has reached the dent stage, which is well behind normal by that date. For most commonly grown corn hybrids, under normal growing conditions, it takes approximately three to four weeks from the “dent” stage until the corn reaches physiological maturity. Of course, if the pattern of cooler than normal temperatures continues, such as most areas have been experiencing in the past couple of weeks, crop maturity could be delayed even longer.

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. 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. So even beyond the corn reaching maturity in the coming weeks, some nice weather conditions will be required to allow for natural dry-down of the corn in the field in order to avoid high corn drying costs this fall. It is likely that a high percentage of the 2019 corn crop will be stored in farm grain storage until the spring and summer of 2020.

There are also many acres of later planted soybeans in portions of the Upper Midwest that will also require favorable growing conditions throughout September in order to reach maturity before the first killing frost. Some timely rainfall events during August in many portions of the Upper Midwest should be favorable for soybean growth and pod setting; however, that advantage has been somewhat offset by the extremely cool weather pattern that has persisted during much of the month.

Based on the August 19th USDA Crop Progress Report, only 55 percent of the corn crop and 60 percent of the soybean crop in Minnesota is rated good-to-excellent, which is well-below crop ratings for mid-August in recent years. The higher crop ratings for corn in other states were 65 percent in Iowa, 73 percent in North Dakota, and 62 percent in South Dakota; however, the good-to-excellent ratings were only 42 percent in Illinois and 32 percent in Indiana and Ohio. The good-to-excellent for soybeans were 61 percent in Iowa, 63 percent in North Dakota, and 56% percent in South Dakota, compared to only 40% in Illinois, 33 percent in Indiana, and 29 percent in Ohio. Nationally, 53 percent of the corn crop and 56 percent of the U.S. soybean crop was rated good-to-excellent on August 19, which compares to 68 percent for corn and 65 percent for soybeans in 2018.

Most crop experts are now agreeing that 2019 crop yields in Minnesota and the surrounding are likely to be highly variable across region. The statewide yield estimates from the recent Pro Farmer crop tour, which is quite extensive and is based on actual field surveys, came in well under the yield estimates in the last USDA Crop Report on August 12. Based on recent history, the USDA yield estimates will be adjusted in coming USDA reports, and the USDA and Pro Farmer projections will end up a lot closer to each other over the next few months.

The 2019 Minnesota corn yield was projected at 173 bushels per acre in the USDA report, compared to 167 bushels per acre in the Pro Farmer (PF) tour. Other estimated 2019 statewide corn yield estimates were Iowa at 191 bushels per acre (USDA) and 181 bushels per acre (PF); South Dakota at 157 bushels per acre (USDA) and 140 bushels per acre (PF); Illinois at 181 bushels per acre (USDA) and 160 bushels per acre (PF); and Indiana at 166 bushels per acre (USDA) and 160 bushels per acre (PF). USDA is estimating the 2019 national average corn yield at 169.5 bushels per acre, compared to a projection of 163.3 bushels per acre (PF).

The situation is similar with 2019 soybean yield estimates. Minnesota is projected at 45 bushels per acre in the USDA report, compared to 42 bushels per acre by Pro Farmer (PF). Other estimated 2019 statewide soybean yield estimates were Iowa at 55 bushels per acre (USDA and PF); South Dakota at 45 bushels per acre (USDA) and 39 bushels per acre (PF); Illinois at 55 bushels per acre (USDA) and 50 bushels per acre (PF); and Indiana at 50 bushels per acre (USDA) and 46 bushels per acre (PF). USDA is estimating the 2019 national average soybean yield at 48.5 bushels per acre, compared to a projection of 46.1 bushels per acre (PF).

While the national yield differences between the USDA estimates and the Pro Farmer projections may not seem that significant, they potentially represent a large difference in the final total 2019 corn and soybean production levels, 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 a difference of 6.2 bushels per acre. Based on the USDA estimate of 82 million harvested acres of corn in the U.S. in 2019, that yield difference represents over one-half billion total bushels of corn.

Many crop advisors point out that the 2019 national and statewide average corn and soybean yields are very hard to predict, due to the wide variability in planting dates and crop conditions across the region. Most also agree that the weather pattern in September and a later than normal killing frost date will be a key to final crop yields in many areas. In Minnesota and the surrounding States, warmer than normal temperatures will likely be required during the month of September, in order to optimize corn and soybean yield potential.