So Far, A Great Start For Corn, But Just An Average Weather Year

Joe Lauer, Corn Agronomist

Weather Graphs PDF

For much of Wisconsin, the 2010 corn crop got off to a great start. Crop progress in some areas is at record pace for development. The crop is ahead of schedule because of early planting dates, rather than significantly different weather. For many farmers the crop is so tall that they are at lay-by in many of their fields. Dr. Bill Tracy indicated that sweet corn inbreds planted May 18 are ready to be shoot bagged - a record early date for him and his crew.

Figure 1 shows the weather data for UW-Agricultural Research Station at Arlington. Precipitation is tracking at a pace similar to the 30-yr normal. Growing degree unit (GDU) accumulation since January 1 is ahead of the 30-yr normal. But, while total GDU accumulation is ahead of schedule, the GDU accumulation for various planting dates is equivalent to the 30-yr normal for every planting date. For a May 1 planting date, GDU accumulation was slower than the 30-yr normal while the crop was emerging, but accumulation has since caught up. Uneven emergence was noted for this planting date in a study at Arlington.

Figure 1. Weather summary for Arlington from April 1 to June 26, 2010

Figure 2 shows the weather data for UW-Agricultural Research Station at Marshfield. Precipitation was tracking at a pace slower than the 30-yr normal, but it has since caught up. Growing degree unit (GDU) accumulation since January 1 is ahead of the 30-yr normal. But, while total GDU accumulation is ahead of schedule, the GDU accumulation for various planting dates is equivalent to the 30-yr normal for every planting date, except for a May 15 planting date. For a May 1 planting date, GDU accumulation was slower than the 30-yr normal while the crop was emerging, but accumulation has since caught up.

Figure 2. Weather summary for Marshfield from April 1 to June 26, 2010

Figure 3. shows the GDU and precipitation deviation of 2010 (April 1 to June 26) from the 30-yr normal. Precipitation accumulation is similar to the 30-yr normal for both Arlington and Marshfield. At both Arlington and Marshfield, GDU accumulation is higher than the 30-yr normal, but less than the four years that were greater than one standard deviation from the 30-yr normal. At Arlington, the production years of 1985, 1987, 1988, and 1991 were warmer than 2010. At Marshfield, the production years of 1987, 1988, 1991, and 1994, were warmer than 2010.

Figure 3. Growing degree unit and precipitation deviation of 2010 (April 1 to June 26) from the 30-yr normal. Other included years were selected using + one standard deviation from the 30-yr normal.

The crop is off to a good start. This is a year that reminds us of what early planting and ideal field conditions during planting can do for corn growth and development. For the most part, weather has been as ideal as it can be, but a lot of growing season is left.