Crop Development Highly Variable

June 5, 2017


The Spring of 2017 has been a battle for some crop producers in portions of the Corn Belt, as they have tried to get corn and soybeans planted on a timely basis. More favorable weather conditions in last few days of May and in early June have allowed for significant planting progress in the some of the hard-hit regions; however, a significant amount of soybeans remain to be planted in the Eastern and Southern Corn Belt, as well as in parts of Eastern Minnesota and Iowa. Frequent rainfall events over the past few weeks has caused further planting delays in some areas, in addition to resulting in drown-out damage in corn and soybean fields that were previously planted.

Total rainfall amounts across Minnesota during the month of May were quite variable. Many areas of Southern Minnesota received above average rainfall during the month of May, with some portions of Southeast Minnesota receiving 5-7 inches of rainfall, or more, during the month. This resulted in delayed planting, as well as some standing water in portions of the region. On the flip side, other areas received less than two inches of precipitation during May, and are actually in need of some rainfall.

The University of Minnesota Research and Outreach Center at Waseca recorded 5.10 inches of rainfall during May, with the largest rainfall event being 1.13 inches on May 21. This was 1.17 inches above to long-term average monthly precipitation for May at Waseca. The U of M Southwest Research and Outreach Center at Lamberton received nearly 6 inches of rainfall during May, which is about 2.5 inches above normal. The largest daily rainfall totals at Lamberton were 1.58 inches on May 18 and 1.45 inches on May 1.

As of May 31, a total of 367 growing degree units (GDU”s) had been accumulated at the U of M Research Center at Waseca since May 1, which is about 4 percent behind normal, and was well behind the 367 GDU’s accumulated by May 31, 2016. Much of the corn in the Upper Midwest that was planted in late April was near normal development for the end of May; however, the crops planted in mid-May or later lagged behind normal development, due to the much cooler than normal temperatures in the last half of the month. The expected warmer temperatures in the next couple of weeks, together with adequate soil moisture, should lead to some improved growing conditions during early June.

Based on the May 28 USDA Crop Progress Report, 96 percent of Minnesota’s corn acreage, and 97 percent of Iowa’s corn crop were planted This compares to five-year (2012-2016) averages of 93 percent in Minnesota and 96 percent in Iowa by that date. By comparison, corn planting progress on May 28 was only 77 percent in Wisconsin and 81 percent in Indiana. Nationally, 91 percent of the corn was planted by May 28, which is 2 percent behind the five-year average. 73 percent of the corn in the U.S. was emerged as of May 28, which is also 2 percent behind normal. Corn emergence in the Western Corn Belt was near normal, while lagging well behind normal in the Eastern Corn Belt.

The May 28 USDA Report showed 81 percent of the soybeans planted in Minnesota, which was ahead of the five-year average of 77 percent planted. Iowa was right on the 5-year average with 77 percent of the intended soybeans planted by May 28. The 2017 soybean planting progress lags behind the 2016 planting progress in both States; however most of the area that remained to be planted is in the highly productive areas of Southeast Minnesota and Eastern Iowa. 67 percent of the U.S. soybean crop was planted by May 28, which is very close to the 5-year average of a 68 percent plant planting pace by that date. Major soybean producing States that lag well behind normal planting progress as of May 28 include Illinois at 62 percent, Indiana and Ohio at 54 percent, and Wisconsin at 45 percent.

In the first national rating on May 28, sixty-five percent of the U.S. corn crop was rated good to excellent, with higher ratings in the Western Corn Belt, and lower ratings in the Eastern Corn Belt. This was the lowest initial corn rating since a 63 percent late May rating in 2013, and compared to the late May U.S. corn condition rating of 72 percent good to excellent a year ago in 2016. Some of the better statewide good to excellent corn condition ratings on May 28 were Minnesota at 68 percent, Iowa at 73 percent, Nebraska at 74 percent, and South Dakota at 67 percent. Some of the lower good to excellent corn ratings were Illinois at 52 percent, Indiana at 43 percent, and Ohio at 49 percent. Approximately 15 percent of the corn in those three States was rated poor to very poor on May 28.

Based on research from the University of Illinois, there is very little correlation between the initial U.S. corn condition ratings in late May and the final U.S. corn yield. By late July, there is about a 90 percent correlation between the national corn condition rating and the final U.S. corn yield. Given the slow start to the 2017 growing season in many key corn producing States, it seems unlikely that the 2017 U.S. corn yield will exceed last year’s record U.S. corn yield, which was slightly above 174 bushels per acre; however, there is still potential for a very good national corn yield this year.

Even though parts of Eastern Corn Belt, as well as selected locations in the upper Midwest, have been dealing with delayed planting and slow early season crop growth, other primary corn and soybean production areas have had much more favorable early season conditions. The overall condition of the U.S. corn and soybean crop at the end of May in 2017 appears to be behind normal, but could likely improve considerably in the coming weeks with some predicted warmer temperatures, and assuming continued adequate soil moisture.


Note — For additional information contact Kent Thiesse, Farm Management Analyst and

Vice President, MinnStar Bank, Lake Crystal, MN.  (Phone — (507) 381-7960);

E-mail —


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