Like the start of a big race, or the beginning of a championship game, farmers in southern Minnesota and Iowa are likely to begin the initiation of full-scale field work during the next week, weather permitting. Now that April 11 has past, 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 2015 corn crop. Any corn that was planted prior to that date is not eligible for replant coverage, if the crop is damaged by frost, heavy rains, or hail damage; however, the crop is still insured with other crop insurance coverage. The earliest planting date for soybeans in Minnesota and Iowa is April 21.
Topsoil conditions this spring have been described as “almost ideal” for corn planting by farm operators and agronomists across southern and western Minnesota. Due to the very limited amount of stored soil moisture in many areas of the region, producers are likely to minimize their tillage trips prior to planting this spring, in order to maintain as much top soil moisture as possible for seed germination and seedling growth. 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 a bit cooler than desirable for the initiation of corn planting in most areas; however, soil temperatures did warm up nicely this past weekend. At the U of M Research and Outreach Center at Waseca, Minnesota, the average soil temperature from April 3-9 ranged from 39.5° to 44.5° F at the 4-inch level, and from 38.5° to 47.0° degrees F at the 2-inch level. These soil temperatures are just slightly above the long-term average soil temperatures for early April at Waseca, but are above the soil temperatures in mid-April of 2014.
Research shows that 50% corn emergence will occur in 20 days at an average soil temperature of 50° F, which is reduced to only 10 days at an average soil temperature of 60° F. 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 2015. There is no need to be in a hurry, or to plant corn before soil conditions are ready. There is an increase in the 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.
2015 is setting up to be the earliest start to spring fieldwork in southern Minnesota since 2012. 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 have struggled with timely corn planting in both 2013 and 2014, due to persistent wet soil conditions.
Most of South Central, Southwest, and West Central Minnesota remains in an extremely dry to moderate drought condition. However, some areas received some beneficial rainfall from April 6-12, which has helped improve the top soil moisture at some locations. Rainfall in several locations of Southeast Minnesota totaled 1.5 to 3.0 inches, or more, which has temporarily alleviated the drought conditions in that region of the State. Overall, sub-soil moisture remains shorter than normal in most portions of the region, which could be a concern if dry weather persists later in the growing season.
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 this year. Historically, early planting of corn usually leads to higher-than-normal state average corn yields. In fact, in four of the six years that 50% or more of the state’s corn acres have been planted in April, Minnesota has set 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. Even in the drought year of 2012, Minnesota had the highest statewide corn yield in the Midwest at 165 bushels per acre, following a very early planting season.