It appears that 2014 will likely be similar to 2013, with a later-than-normal initiation of spring fieldwork in many areas of the Upper Midwest. This year, we are not likely to see much full-scale field work in much of southern Minnesota until after April 20, and it will probably be late April or early May before a significant amount of corn is planted. Soil temperatures are still well below minimal acceptable levels for planting corn, and there is still a considerable amount of frost in the ground in most areas. Some portions of Central Minnesota still have significant snow cover to melt. As recently as 2012, most farmers in Southern Minnesota and Iowa began full-scale fieldwork during the week of April 10-17, with most of the corn being planted by the end of April.
At the U of M Research and Outreach Center at Waseca, Minnesota, the average soil temperature at the 2-4 inch level in the first few days of April ranged from 30.0 to 35.0 degrees F., which are similar to 2013 soil temperature levels in early April. The recent average soil temperatures are below the long-term average soil temperatures for early April at Waseca of 38- 40 degrees F. at the 2-4 inch level. The “ideal temperature window” for planting corn is 50-55 degrees F. at the 2-4 inch soil depth. In many areas of Southwest and South Central Minnesota, frost depths of 4-5 feet under bare ground were still quite common at the end of March.
Early corn planting in the Upper Midwest is usually one of the key factors to achieving optimum corn yields in a given year. University of Minnesota and private seed company research seems to indicate that the ideal planting dates for corn in Southern Minnesota are typically April 15 to May 5. However, the ideal planting date for corn varies somewhat from year-to-year depending on soil temperatures and soil conditions. Research shows that 50 percent corn emergence will occur in 20 days at an average soil temperature of 50 degrees Fahrenheit, which is reduced to only 10 days at an average temperature of 60 degrees F.
Unless conditions turn very favorable in the next couple of weeks, we are not likely to see near as much corn planted in Minnesota by the end of April, compared to recent years, prior to 2013. Historically, early planting of corn usually leads to higher than normal state average corn yields. In fact, in five of the six years that 50 percent or more of the State’s corn acres have been planted in April, Minnesota has either set or been close to a record corn yield.
In 2010, a large percentage of corn was planted in April, and Minnesota had a State record corn yield of 177 bushels per acre. In 2012, a large percentage of the corn was also planted in April, and the statewide average corn yield was 165 bushels per acre, while in 2013, most corn in Minnesota was planted in mid-late May, resulting in a statewide average yield of 160 bushels per acre. Both 2012 and 2013 experienced very dry growing conditions during late Summer in some areas of the state, but the earlier planting date probably was the main reason for the higher statewide yield in 2012. The biggest “wild card” in the 2014 growing season may be the limited stored soil moisture and dry conditions that still exist in many portions of the western half of Minnesota.
Most University and private agronomists are encouraging producers to be patient with the initiation of corn planting in 2014. There is no need to be in a hurry and to plant corn before soil conditions are ready. Planting corn into poor soil conditions increases the likelihood of poor emergence and slow early season growth. In addition, anytime corn planting in Southern Minnesota and Northern Iowa occurs before mid-April, the likelihood of potential frost damage increases.