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 fieldwork on April 11, or shortly after. April 11 is the earliest corn-planting date allowed by the USDA Risk management Agency (RMA), in order to maintain full crop insurance replant coverage on the 2012 crop. Corn planted prior to April 11 is not eligible for replant coverage, if the crop is damaged by frost, heavy rains or hail; however, the crop is still insured with full crop insurance coverage, as long as the producer follows all other crop insurance requirements. The earliest planting date for soybeans in southern Minnesota and Iowa is April 21.
The very warm temperatures during the last half of March and the first few days of April resulted in soil temperatures very conducive to corn planting in most areas. Topsoil conditions for corn planting have been described as “almost ideal” by farm operators and agronomists across southern Minnesota this spring. Due to the very limited amount of stored soil moisture in many areas, 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.
At the U of M Research and Outreach Center at Waseca, MN, the average soil temperature at the 4-in. level from April 2 to 6 ranged from 54.0° to 58.5° F, and from 56.5° to 61.5° F at the 2-in. level, which are well within the “ideal temperature window” for corn planting. These average soil temperatures are more typical of early May than early April in southern Minnesota. The long-term average soil temperatures for early April at Waseca are just above 38° F at the 4-in. level, and near 40° F at the 2-in. level.
This year is setting up to be one of the earliest starts to spring fieldwork in many years. 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 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% 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 temperature of 60° F.
Most university and private agronomists are encouraging producers to be patient with the initiation of corn planting in 2012. There is no need to be in a hurry and to plant corn before soil conditions are ready. Any time that corn planting in southern Minnesota and northern Iowa occurs before mid-April, the likelihood of potential frost damage increases.
Most of southern Minnesota and northern Iowa remains in a moderate to severe drought; however, rainfall events in some areas in late February and March have helped improve the topsoil moisture at some locations. Rainfall at Waseca in March had totaled 1.93 in., which along with the 1.96 in. received on Feb. 29, resulted in 3.89 in. of precipitation in slightly over one month. Other areas of southern Minnesota received far less rainfall than Waseca during that period. Overall, Sub-soil moisture remains extremely short 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, most corn in southern Minnesota should be planted well before the end of April, and a large percentage of corn across the state should be planted in April. Historically, early planting of corn has usually led to higher-than-normal state average corn yields. In fact, in four of the five 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 record corn yield of 177 bu./acre. The biggest “wild card” in 2012 may be the limited stored soil moisture and dry conditions that exist in many portions of southern and western Minnesota
Spring applications of anhydrous ammonia and livestock manure are nearly completed in many areas. Soil conditions this spring have been much better for anhydrous application than they were with the very dry soil conditions following harvest in 2011. Farm operators have also been planting wheat, oats and other small grain crops, as well as alfalfa and early peas, in the past couple of weeks. The early alfalfa growth looks very good in most areas, with very limited winter injury.
Editor’s note: Kent Thiesse is a former University of Minnesota Extension educator and now is Vice President of MinnStar Bank, Lake Crystal, MN. You can contact him at 507-726-2137 or via e-mail at [email protected].com.