News Story

2017 Central Farm Service Corn Yield Tour

Brian Weller, Lead Agronomist

As we have done in the last few years, Central Farm Service has done a Pro Farmer/Farm Journal type of tour on corn fields in our area. We have typically done this tour in August, but in the last few years we have delayed the tour to closer to harvest. The reason for pushing the tour back, is to get a better look at stalk quality and standability/harvestability, as well as the potential impact of a frost or other weather event on yield.

            The tour was completed September 10-16 during a period of time with warmer temperatures that had daily highs in the mid to upper 80°F’s. These warmer temperatures were welcomed, due to the fact that we experienced a cooler than normal growing season where Growing Degree Units (GDU’s) were lower than anticipated. Our warmer temperatures were accompanied by a mainly southerly breeze that had winds averaging 15+MPH and a few sustained gusts 25 MPH or slightly more. During our Corn Yield Tour week, the crop seemed to be noticeably pushed closer to harvest every day. This sudden change in the crop could be attributed to the warmer temperatures and wind but also the lack of moisture for the week, as well as a shallower root system on most plants.

            During the tour, Greensnapped plants were visible in many fields, the saving grace is that it appeared to be 1% or less of the plants were affected. We did see Goosenecked plants especially in areas that experienced high winds, hail events or tornado like conditions.


            Standability issues may become more of a concern the later into harvest we get. It is my belief that many of these standability issues can be traced back in some part to compaction issue that we created last fall while harvesting. These compacted soils are more likely to have more nutrient deficiencies, due to the corn plants inability to penetrate deeper into the soil profile to access nutrients. These deficiencies cause cannibalization of stalks and leaves to start which takes nutrients from the stalk and leaves, and moves them into the ear and kernels. Additional factors that may affect standability this fall are:

  • Diminished root system due to frequent rainfall amounts that allowed the plant not to have to grow deeper into the soil profile in search of water
  • Cloudy days after pollination which reduced photosynthesize may have forced the plant to cannibalize the stalks sooner
  • Cooler temperatures reducing the Growing Degree Unit (GDU) accumulation may force the plant to cannibalize nutrients within stalk and leaf surface to fill kernels
  • Good yield potential which will cause the plant to cannibalize the stalk and leaf surface area to fill the kernels
  • High wind and hail events which have caused some Goosenecking and root lodging as well as bruised stalks
  • Nutrient deficiency caused by previous high yielding crops removing nutrients, and those nutrients not being replaced by manure or fertilizer or the reduction in the amount of manure or fertilizer that was applied.
  • Soil pH issues either too high or too low will cause nutrient deficiencies

Early harvest is still highly recommended to capture the highest yields and to reduce the standability issue. The cost of propane may have increased over last year, but is still lower than the previous years, this reduced cost will make the recommendation to harvest earlier and not let the crop dry in the field easier to make.

            Individual ear/kernel count yield estimates ranged from 84.85 bu/acre on the low end of the spectrum to 318.73 bu/acre on the high end. The lowest estimated field average is 137.24 and the highest estimated field average is 229.49 bu/acre. The average of all fields for estimated yields for 2017 is 189.59 bu/acre, this is 4.79bu/acre more than the 2016 average estimated yields of 187.8 bu/acre.

2016 Average Estimate

2017 Average Estimate






            Not to confuse the issue, but we have always done an Adjusted Yield based off of the Average Estimate Yield. We have never brought forth the information from the Adjusted yield because it was not “just the facts” and more of a gut instinct after walking fields. We are changing that in 2017, and will be providing that Adjusted Yield or gut instinct information, as well as historical comparisons between Averaged Estimated Yield and Adjusted Yield.

The average of all the Adjusted Yields for 2017 is 196.88 bu/acre which is 2.78 bu/acre less than the 2016 Adjusted Yield of 199.66 bu/acre.

2016 Adjusted Yield

2017 Adjusted Yield






Listed below is the comparisons that we have had with the Estimated yield and the Adjusted Yield, as well as the number of stops that the yield tour made for the season. It is always interesting to see from an historical perspective what yields have done, and the number of stops that were made during the tour.


Average Estimate Yield

Adjusted Yield



























            The overall consensus from the tour is that we will have good yields this fall, but with the expectation that we will be 5-10 bushels less than last year due to reduced stands establishment this spring and compaction.

            Other concerns affecting yield are mobile nutrient deficiencies such as Nitrogen and Sulfur. We started to see Nitrogen deficiencies as early as mid-July and once they start to show up they continue to advance up in the plant, from the bottom leaf up, until the plant is dead. The photos below show Nitrogen deficiency from mid/late July.


The photos below show Nitrogen deficiency in plants close to black layer or Physiological Maturity (R6). I do not like to see corn plants with leaves that have nitrogen deficiency at the ear or above the ear prior to R6. I want the 2-3 leaves below the ear to be green and show no Nitrogen deficiency prior to R6. Nitrogen deficiency this high in the plant prior to R6 may cause the rate of cannibalization to increase, which will in turn reduced the standability of the corn plant.

            Another nutrient deficiency that has started to show up at the end of the season but is tough to photograph is Sulfur deficiency. Sulfur deficiency starts at the top of the plant and starts to work its way down. Much like late season Nitrogen deficiency, Sulfur deficiency increases cannibalization, which in turn will affect standability.

            Another yield limiting factor that was more prevalent this year than in years past has been reduced weed control. (Photo on right is N deficient and poor foxtail control)



We saw reduced control of both grass and broadleaf species in many fields during the tour. This has not normally been the case in the history of the tour. It is my belief that in trying to cut costs producers:

  • Reduced rates of herbicides and adjuvants and did not have an adequate rate or coverage on targeted weeds which reduced control
  • Utilized products formulated with less than adequate rates of Active Ingredients to kill targeted weeds such as Waterhemp species, Giant Ragweed, Velvetleaf and Foxtail species in an attempt to be competitive in price

The 2017 Central Farm Service Corn Yield Tour had a goal of 55 stops and ended up with 65 stops for the year. The area covered was from Dolliver Iowa on the southwest corner to Comfrey Minnesota on the northwest corner, and then proceeding at a northeasterly direction to Nicollet with the far northeasterly stop being in the Hastings Minnesota area. The eastern border of the tour was from Hastings Minnesota down to Cannon Falls, Wanamingo, Kasson and with the far southeastern stop being Rose Creek Minnesota. The southern border Rose Creek to Myrtle, Emmons and then angling southwesterly towards Dollliver Iowa.