The growing season started above normal for growing degree days and then paralleled the 30-year normal accumulation pattern through April and May. Over the last couple of weeks during June, growing degree accumulation has increased compared to the normal.
Precipitation in northern Wisconsin is comparable to the 30-yr normal. But, in southern Wisconsin accumulated precipitation is below normal and approaching some of driest years recorded (1976, 1988, 1989, and 2005). The southern four tiers of Wisconsin counties are most affected. Other parts of the Midwest Corn Belt have seen rain showers move in east-west bands, so drought stressed fields are more random. Fields with no water stress are often located near fields showing significant water stress.
We need rain soon. Corn is heading into pollination and potential grain yield will be determined soon after fertilization takes place following pollen shed and silk emergence. For more information on weather patterns of previous years, click here.
Managing corn during and after a drought http://corn.agronomy.wisc.edu/Management/L046.aspx.