Crop conditions across much the Midwest have been quite favorable through most of the growing season until late July, especially in the high-producing corn and soybean production states of Iowa, Illinois and Indiana, as well as other adjoining states. Crop conditions in a large segment of Minnesota, as well as some areas in adjoining states have been much less favorable during most of the growing season, due to the significant amount of late and prevented planting, along with excessive rainfall in many areas during June.
As of July 23, a total of 1,283 GDUs had been accumulated since May 1 at the U of M Southern Research Center at Waseca, Minnesota, which is about 5% behind normal for that date. The GDU accumulation at Waseca has consistently been about 2-5% below normal since early May. By comparison, on July 23, 2013, GDU accumulation at Waseca was near normal, and corn and soybean development in southern Minnesota was making rapid progress, following late planting and poor early season growing conditions in 2013.
A majority of the corn and soybeans in southern and western Minnesota were planted one to two weeks later than normal in 2014, or even later in portions of central Minnesota. Crop development in most of Minnesota and adjoining areas in neighboring states has been 7-10 days behind normal since early May. Long-range weather forecasts continue to call for below-normal temperatures for the Upper Midwest for the next two weeks, which will not be conducive for enhancing crop development. The later than normal planting, together with the cooler than normal growing season, means that some above-normal temperatures will likely be needed for the balance of the growing season to assure that crops properly reach maturity.
Corn takes about 60 days from the time of tasseling and pollination until the corn kernels reach black-layer with normal accumulation of GDU’. Once the corn kernel is black-layered, it is usually free of significant damage from a killing frost. Much of the earlier planted corn in southern Minnesota tasseled and pollinated from July 20 to 26, and should adequately mature in 2014, assuming fairly normal GDU accumulation in August and early September, and a normal date for the first killing frost. Some of the later planted corn in central Minnesota and other areas, which is tasseling in late July or early August could have some challenges being fully black-layered by the first frost, especially if temperatures stay cool, or if the first killing frost is earlier than normal. Corn also will likely have higher moisture content at harvest this Fall, which will increase drying costs.
There are similar concerns with soybean maturity, as thousands of acres of soybeans in Minnesota and surrounding states were planted in June. The cooler-than-normal weather pattern has increased concerns regarding the late planted soybeans reaching maturity before the first killing frost. Overall, most soybeans in many areas of southern Minnesota and northern Iowa are behind normal, however, in most portions of the region, the overall condition of the soybean crop has improved considerably in recent weeks. The weather pattern in August will likely be the key factor for final determination of 2014 soybean yields.
Interestingly, after the excessive rainfall amounts in June, some areas of Southern and Western Minnesota were starting to get quite dry by late July. Many locations had received less than an inch of rain during July, before some scattered showers occurred over this past weekend. Moderate rainfall during corn tasseling and pollination can be quite beneficial for final corn yields.