Like the start of a big race, or the beginning of a championship game, farmers in southern Minnesota and northern Iowa are likely to begin the initiation of full-scale field work during the next week, weather permitting. Now that April 11 has arrived, which is the earliest corn planting date allowed by the USDA Risk Management Agency (RMA) in order to maintain full crop insurance replant coverage, producers will have full crop insurance coverage for the 2016 corn crop. Any corn that was planted prior to that date is not eligible for replant coverage; however, if the crop is damaged by frost, heavy rains or hail during the growing season, the crop would still be insured with other crop insurance coverage. The earliest planting date for soybeans in Minnesota and Iowa is April 21.
Soil conditions this spring have been described as “fit for corn planting” by farm operators and agronomists across southern and western Minnesota; however, persistent cool soil temperatures have been a concern. Due to manageable amounts of topsoil moisture in most parts of the region, producers should be able to proceed with tillage and planting, without dealing with major wet areas of fields. Some producers have already seeded small grain and alfalfa crops, and have made spring applications of nitrogen fertilizer and livestock manure.
Soil temperatures have remained cooler than desirable for the initiation of corn planting in the Upper Midwest; however, soil temperatures are expected to warm up rapidly in the coming days. At the University of Minnesota Research and Outreach Center at Waseca, the average soil temperature from April 1 to 8 averaged 41.4° F at the 4-inch level, and just 42.1° F at the 2-inch level. These soil temperatures are slightly below the long-term average soil temperatures for early April at Waseca, and are also slightly below the soil temperatures in early April 2015. A year ago, soil temperatures started warming up in mid-April, and remained at almost ideal levels for the balance of the spring planting season.
Research shows that 50 percent corn emergence will occur in 20 days at an average soil temperature of 50° F, which is reduced to only 10 days with an average soil temperature of 60° F. In 2015, most corn germinated and emerged in around two weeks; however in 2014, some early-planted corn took 30-40 days to emerge, due to very cool soil conditions. Most agronomists are encouraging producers to be patient with the initiation of corn planting in 2016. There is no need to be in a hurry, or to plant corn before soil conditions are ready. There is an increased likelihood of potential frost damage when corn is planted in mid-April; however, most producers are willing to take that risk, given the extra yield potential of the earlier-planted corn.
Most portions of southern Minnesota and northern Iowa are in reasonably good shape for stored soil moisture as we head into the 2016 growing season. The U of M Research Center at Waseca received over 8.5 inches of precipitation in late fall and early winter 2015, and has received some additional precipitation this spring. Conditions are a bit drier in southwest Minnesota. Some portions of west-central and northwest Minnesota, as well as in the eastern Dakotas, have received much less precipitation in late 2015 and early 2016, and have more limited amounts of stored soil moisture. If the sub-soil moisture remains shorter than normal in these areas, it could become a concern later in the growing season, especially during any extended dry weather patterns.
2016 is setting up to be the second year in a row of a fairly early start to spring fieldwork in southern Minnesota. Early corn planting in the Upper Midwest is usually one of the key factors to achieving optimum corn yields in a given year. But how early is too early? University of Minnesota and private seed company research seems to indicate that the ideal planting date for corn in Southern Minnesota is typically from April 15 to May 7. However, the ideal planting date for corn varies somewhat from year-to-year depending on soil temperatures and soil conditions.
Producers in many portions of the region achieved almost optimum corn and soybean planting dates and conditions in 2015, but struggled with timely planting in both 2013 and 2014, due to persistent wet soil conditions. The result was record corn and soybean yields in many portions of the region in 2015, and below-average crop yields in many areas in 2013 and 2014.
Unless conditions turn very wet in the next couple of weeks, a large majority of corn in Minnesota could be planted before the end of April again this year, similar to 2015. Historically, early planting of corn usually leads to higher than normal state average corn yields. In fact, in five of the seven years that 50 percent or more of the state’s corn acres have been planted in April, Minnesota has set a record corn yield. Last year, Minnesota had a record corn yield of 188 bushels per acre, besting the previous record of 177 bushels per acre, set in 2010. Even in the drought year of 2012, Minnesota had the highest statewide corn yield in the Midwest at 165 bushels per acre. In all three years, a majority of the state’s corn crop was planted by the end of April.