During March, several all-time record temperatures have been set in Minnesota and Iowa. At the University of Minnesota Research and Outreach Center at Waseca, the 2012 high temperature hit 79° F four straight days from March 17 to 20, and set seven record March high temperatures March 21. By comparison, the highest March temperature at Waseca in 2011 was 49°, 60° prior to March 30 in 2010, and 64° in 2009. The average 2012 March temperature through March 21 at Waseca was 44.5°, compared to a normal average March temperature of 30.3°, and a 2011 average March temperature of 26.9°.
Most of southern Minnesota and northern Iowa remain in a moderate to severe drought; however recent rainfall events in some areas have helped improve the top soil moisture in some areas. Rainfall at Waseca in March had totaled 1.11 in., as of March 21, which along with the 1.96 in. received on Feb. 29, has resulted in slightly 3.50 in. of precipitation in the past four weeks. 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.
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 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 10 days at 60°. Average soil temperatures in the 2-4-in. zone at Waseca since mid-March have generally been in the 55-60° range, which is almost ideal for corn planting. These soil conditions are more typical of early May. The long-term average 2-4-in. soil temperature at Waseca on April 1 is about 37.7°.
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 corn planting in southern Minnesota and northern Iowa occurs before mid-April, the likelihood of potential frost damage increases. This situation becomes more likely with warm soil conditions and adequate topsoil moisture, which will allow corn to germinate and emerge more quickly. Also, a cool, wet weather pattern following plating could result in slow germination and poor emergence of young corn plants, leading to some stand reductions. On the other hand, early corn planting should result in earlier tasseling and pollinating of the corn, which could be a benefit if there is a warmer and drier than normal weather pattern in the summer in 2012.
Some farm operators have begun applying spring anhydrous ammonia as a source of nitrogen (N) for the 2012 corn crop. Soil conditions in late March across south-central Minnesota are in better condition for anhydrous application than they were following harvest in 2011. Very dry, cloddy soils in fall 2011 resulted in very poor conditions for fall N applications, leading some producers to delay applications until this spring. Livestock producers have also been making manure applications to fields in recent weeks. Very little small grain is planted in southern Minnesota; however, seeding of wheat, oats and other small grains is likely to begin in the coming days for farm operators that grow those crops.