Spring fieldwork has been slow to begin in most areas of Upper Midwest in 2017, with conditions in most areas vastly different than last year. Except for a few brief stints, very cool temperatures have existed across the region during most of the month of April, resulting in soil conditions that have not been conducive to corn planting in Minnesota and Northern Iowa. In addition, heavy rainfall this past weekend across large areas of the region have further added to the planting delays, Farm operators in some areas did plant a small amount of corn from April 23-25; however, there is now concern about the seedling viability of the corn that was planted prior to the extended cool, wet weather pattern that existed in late April across the region.
At the University of Minnesota Research and Outreach Center at Waseca, Minnesota, the average soil temperature on April 27 was only slightly above 50 degrees Fahrenheit (F) at the 2-4 inch level, and had declined to the mod 40’s over this past weekend. These soil temperatures are too cold for good corn seed germination and early corn seedling development. The long-term average soil temperatures at the end of April at Waseca are more typically in the mid-50’s at the 2-4 inch level. Research shows that 50 percent corn emergence will occur in 20 days at an average soil temperature of 50 degrees F, which is reduced to only 10 days at an average temperature of 60 degrees F.
Farm operators in many areas of the Upper Midwest will also now need to deal with wet field conditions, in addition to hoping for warmer temperatures, to either begin or resume corn planting. Many locations received an inch or more of rainfall this past weekend, with some areas receiving in excess of two inches, and other areas receiving some wet snowfall. There is now ponding of water in some fields, which may require several days to dry out, before field work and planting can again be initiated. The good news is that the long-range forecast calls for a drier weather pattern and warmer temperatures, which should result in improved planting conditions as we head into mid-May.
Most University and private agronomists are encouraging producers to be patient with resuming field work, and to wait until soil conditions are conducive for good corn planting and seed germination. Given the high cost per acre of seed corn, and the limited availability of some of the best yielding corn hybrids in 2017, most growers do not want to take the risk of planting corn into poor soil conditions. Normally, in early May, the soil temperatures warm up quite rapidly, so concern over cool soil temperatures becomes less of an issue. It is expected that full-scale corn planting will resume as soon as the field conditions dry out, and are fit for planting. Most likely, farm operators will move directly into soybean planting, once they have completed their corn acres.
According to University of Minnesota and private seed company research, the “ideal time window” to plant corn in Southern Minnesota in order to achieve optimum yields is typically from about April 20 to about May 7. Even though Spring planting is off to very slow start, compared to recent years, the good news is that there are still opportunities for timely corn planting. Based on long-term research, the reduction in optimum corn yield potential with planting dates from May 5-15 in Southern Minnesota is usually very minimal, and is very dependent on the growing season weather that follows. Even corn planted from May 15-25 has a good chance of producing 90-95 percent of optimum yield potential, assuming that we get some favorable growing conditions in 2017. The ideal window to plant soybeans in Southern Minnesota and Northern Iowa, and still get optimum yields, extends until about May 25, so there is still plenty of time to get the 2017 soybean crop planted.
Some Agronomists have also expressed concern for the corn that was planted from April 23-25, due to the extended cool, wet soil conditions that have followed. The concern is due to the potential for poor germination and reduced seedling vigor once the corn is germinated. However, other agronomists point to the fact of the improved corn hybrids that are in existence today, which should have the ability to withstand more variable early season soil conditions, and not have corn stands significantly reduced, or yield potential affected. In a few weeks, we will probably know if the concerns that have been raised with the early planted corn do in fact become a serious issue.
According to the USDA Weekly Planting Progress Report on April 24, only 6 percent of the corn in Minnesota had been planted, compared to an average of 17 percent by that date. In 2016, when Minnesota achieved a record statewide corn yield of 193 bushels per acre, about 40 percent of the State’s corn crop was planted by April 24. Of course, soil temperatures and planting conditions were much more favorable in 2016 than have existed in April of this year. In Iowa, an estimated 8 percent of the corn had been planted by April 24, which is about nine days behind the planting progress in 2016. Nationally, 17 percent of the U.S. corn crop was planted by April 24, compared to a normal planting level of 18 percent by that date, and compared to 28 percent planted by that time in 2016.