2017 Yield Expectations


In general and depending on location, corn yields have been greater than expected and soybean yields have varied depending on planting date and product maturity.

Rainfall (high and low) tended to be the element that drove the concerns of potential corn yields. Much of central and northern Illinois and northern Indiana were able to plant corn on a timely basis; however, areas of east central Illinois and much of central Indiana were delayed in planting because of excessive rainfall (Figure 1).


Figure 1. Rainfall totals from April 26 to May 5, 2017.1 (Permission to use granted by Dr. Jim Angel)


Figure 2. Rainfall totals from June 6 to July 6, 2017.2 (Permission to use granted by Dr. Jim Angel)

As the calendar moved into July, much of the area was dry with the major exception being far northern Illinois and central Indiana (Figure 2). The shortage of moisture and high heat in July brought the fear of lower potential yields as corn was pollinating. However, though July rainfall was limited, the rainfall that did occur was timely and helped sustain the crop through pollination.


Figure 3. Midwest August temperature departure from normal.3 (Permission to use granted by Dr. Jim Angel)

August continued to be dry but temperatures throughout the region were below normal (Figure 3). Without excessive heat on dry fields, the plants were able to continue to develop. The hot July may have limited kernel row number but the cool August allowed the fertilized kernels to become deeper and wider (Figure 4). The larger kernels helped increase reported yields.


Figure 4. DEKALB® brand corn kernel from 2017 production compared to a penny.

Soybean yields have been variable and appear to be fluctuating around planting date and soybean maturity. Early planted and early maturing soybean fields have tended to be yielding more than later planted fields because of favorable early growing conditions.4 Though August and September were dry, the cooler temperatures helped decrease the effects of low rainfall and helped increase pod numbers and their fill on later plantings and later maturity products; however, reported yields were trending lower because of the limited rainfall and cooler temperatures.

Farmers utilizing Climate FieldView™ technology and reports were able to identify potential problem areas such as drowned out areas early in the growing season and adjust potential yield forecasts accordingly. Additionally, the early knowledge may have allowed for additional nitrogen to be sidedressed into field areas that were showing nitrogen deficiencies from saturated soils.

Sources: 1Angel, J. 2017. Rainfall over the last 2 weeks in Illinois. Illinois State Climatologist.; 2Angel, J. 2017. Dryness across Illinois. Illinois State Climatologist.; 3Angel, J. 2017. Chilling in Illinois. Illinois State Climatologist.; 4Quinn, L. 2017. Illinois corn and soybean harvest considerations. News Release. University of Illinois. Web.extension.illinois.edu/state/newsdetail.cfm?NewsID=35763. Pest & Crop Newsletter. 2017. Purdue Cooperative Extension Service. Purdue University. Pack, D. 2017. Spotty weather has Indiana grain crops off to an uneven start. Agriculture News. Purdue University. 171016085619