Crops Move Closer To Maturity

Above normal temperatures in mid-September have helped the 2019 corn and soybean crop move somewhat closer to reaching maturity. As we entered September, there was a great deal of concern about crop maturity, due to the very late planting dates this year in many areas of the Upper Midwest, as well as in the Eastern Corn Belt. Even though the warmer weather has helped ease the crop maturity issues a bit in some areas, there are still plenty of concerns remaining as we head into the Fall harvest season.


At the University of Minnesota Research and Outreach Center at Waseca, MN, the week of September 12 to 18 had an average daily temperature of 67.4 degrees, which is 5.8 degrees above normal. The growing degree unit (GDU) accumulation during the week was 122.8 GDU’s, which is 38% above normal. As of September 18, a total of 2,279 GDU’s had been accumulated at the Waseca location since May 1, 2019, which is still about 5 percent below normal and is more than 390 GDU’s behind the 2018 GDU level in mid-September. There are still some major concerns with crop development and maturity, especially in Southwest Minnesota, Northwest Iowa and Eastern South Dakota, where corn and soybeans were planted 2-4 weeks later than normal.


Based on the September 15 USDA Crop Report, it was estimated that 59 percent of the corn crop in Minnesota had reached the “dent” stage, which compares to a normal rate of 88 percent by that date. For most commonly grown corn hybrids, under normal growing conditions, it takes approximately three to four weeks from the “early dent” stage until the corn reaches physiological maturity. It takes about two weeks for corn to reach maturity once the corn reaches the “hard or full dent” stage.


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, which will also require favorable growing conditions in the next few weeks in order to reach maturity before the first killing frost. Soybeans normally require about two weeks to reach maturity once the leaves start turning colors. Based on the USDA Crop Report for September 15, only 47 percent of the soybeans in Minnesota were turning color, compared to a normal rate of 77 percent by that date. The normal first frost dates in Southern Minnesota are from October 1 to 14, depending on location.


Many areas of Southern Minnesota and Northern Iowa reported heavy rainfall, and even some hail and wind damage, during the week of September 8-14, with additional rainfall in some areas during the week of September 15-21. Most areas of Southern Minnesota have received 4-6 inches of rainfall in September, with some areas of Southwest Minnesota receiving 8-10 inches of rainfall. This type of intense rainfall is unusual in September, being more likely to occur in the Spring and early Summer; however, it also occurred across the same region in both 2016 and 2018. The strong winds and hail that occurred in some locations also caused additional crop damage.


There will likely be some additional crop loss, along with potential delays in the 2018 corn and soybean harvest, in the areas that were most severely impacted by the recent heavy rainfall events. The corn and soybean fields near any rivers, streams or creeks, as well as in most other low lying, poorly drained portions of farm fields, were under water following the heavy rainfall events. In many cases, fields in these same areas had been damaged or were not planted in 2019, due to damage from excessive rainfall earlier in the growing season.


Most farmers in Southwest Minnesota, Northwest Iowa, and Eastern South Dakota are now dealing with completely saturated soil conditions, which could potentially delay soybean and corn harvest in portions the region. The immediate impact of the wet field conditions has been for dairy and beef producers that are trying to harvest corn silage, as corn development is currently at the right stage for high quality silage harvest. In hardest hit areas, it may take a week or longer of dry conditions for fields to be fit to resume silage harvest, and farmers may be forced to leave a potion of fields until the soils dry out. In many portions of this region, the corn and soybeans have not yet reach maturity, so there is some time for fields to dry out before full-scale grain harvest begins.


The crop damage and potential harvest problems are especially difficult for affected crop producers that are facing very tight profit margins in 2019. Farm operators in many portions of Southern Minnesota, Northern Iowa, and Eastern South Dakota were already looking at reduced crop yield potential, due to poor growing conditions early in the growing season. Now, many producers are in a “wait and see” mode regarding corn and soybean harvest, hoping that the yields on the remaining crop acres are strong enough, in order to offset yield losses in the portions of fields that were impacted by the heavy rains and flooded conditions.



Farm operators with crop losses need to contact their crop insurance agent prior to harvesting fields with significant crop losses to make sure that those losses are reported and verified. Producers also need to keep good yield records, and follow crop insurance verification procedures, in order to maximize crop insurance indemnity payments on damaged crop acres. Crop insurance indemnity payments will vary from farm-to-farm, depending on the type of insurance and the level of insurance coverage that was purchased for the 2019 crop year, as well as the final 2019 corn and soybean yields. The current lower price levels for corn and soybeans increases the likelihood of crop insurance payments for producers with Revenue Protection (RP) crop insurance policies. Producers should contact their crop insurance agent for more details.



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

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

E-mail — Web Site —


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