Sep 23, 2014
Home| Tools| Events| Blogs| Discussions Sign UpLogin

PFA Pioneer Blog

RSS By: Chip Flory, Pro Farmer

This is a private blog for Pioneer.

How we do what we do on Midwest Crop Tour

Aug 09, 2013

Pro Farmer Extra

- From the Editors of Pro Farmer newsletter -

August 9, 2013

We're getting a few questions about the details of how we collect corn and soybean yield samples on the Pro Farmer Midwest Crop Tour, so I thought I'd use the space here to explain how we do what we do.


Scout teams travel in teams of four per vehicle, and because of the number of scouts we've got coming, some routes will carry two cars. Each route will have at least one farmer, agronomist or experienced crop scout to help keep less-experienced scouts on track and to answer any crop questions that might come up.

The eastern leg of the Tour will run 12 routes because we've been running 12 routes for the past several years. With more scouts coming on Tour, we were tempted to add routes, but there are only "so many" paths to follow to get from one overnight location to the other. If we added routes, we'd get routes too close together in bottleneck areas and we'd start to collect too many samples from too small an area, weighting the state to that area. Adding routes would also start to skew our ability to compare this year's results to past years, and that's the last thing we want to do.

The western leg of the Tour will run 10 routes. Routes are driven by scouts that volunteer to bring their personal vehicle.


One of the ways we keep the Tour consistent from year to year is by running the same routes each year. That makes sure we're comparing conditions from the same areas year-to-year.

We do not, however, tell scouts which fields at which to stop. That helps keep the process random. We encourage scouts to stop every 15 to 20 miles, making sure they stop at least once in every county their route runs through. We encourage each route to bring back at least 15 corn and 15 soybean samples each day.

We discourage "cherry-picking" of fields. The way I do it is simple. When the odometer says we're close to a stop, I say we're going to take the next turn to the right (or left) and take the first corn, soybean combination we come to.

It's often easiest to stop close to the gateway to the field, but we ask scouts that if they do enter a field through the gate to turn either left or right and walk away from the gate to get away from compaction areas.

In corn fields, we also get past the end rows and then walk 35 paces down the main rows before laying out the plots. Corn plots consist of two, 30-foot rows that are laid out by hooking a 30-foot rope on the stalk at the end of the 35th pace and we measure away from our entry into the field.

In soybean fields, we don't go that deep into the field. In most years, getting past the end rows and 35 paces down the main rows would leave an "impressive" path behind us. Instead, we get away from the compaction area and go to a "representative" spot in the field, but we do get beyond the end rows if possible. At the representative spot, we lay out a 3-foot plot on one row.


After laying out the 30-foot plot in corn, we count all the ears that will make grain (we don't count ear-shoots that feel like rolled up wet paper towels when you squeeze them). We do count second ears if they will make grain, and we always count the primary ear first and second ear second when we are counting ears. We record the total number of ears counted on the two rows.

We pull the 5th, 8th, and 11th ear from one row (three ears total). Doing this helps keep the process consistently random... we might pull the three best, three worst or a combination or good and poor when we do this. Pulling the 5th, 8th and 11th ear also prevents "cherry picking" and pulling only big ears or small ears. The reason we always count the second ear on a stalk second is because if the second ear is the 5th, 8th or 11th ear, we will pull the second (normally smaller) ear as part of the sample.

We head back to the car and count (and average) the number of kernel rows around the three sample ears and measure the length of grain in inches (and average). I stress, we measure only the length of grain... we don't measure from the butt of the ear to the tip of the cob.

We also record the row spacing in each field.

In soybean fields, we count all the plants in the 3-foot plot. We then pull three plants at random and take them back to the car. We then count all the pods that measure at least 1/4 inch on each plant and calculate the average number of pods per plant.

We also record the row spacing in each field.


The average number of ears in 30-foot of row X the average number of kernel rows around the ear X the average length of grain... then divide by the row spacing.

It might look something like this:

(50 X 16 X 6.5)/30 = 173.3 bu. per acre.


We don't estimate soybean yields... there is still way too much to be determined after Tour to accurately calculate a yield estimate with the data we collect. What we do is calculate the number of pods in a 3'X3' square so that pod counts from a 30-inch rowed bean field can be compared to a 20-inch rowed field or to a 7.5-inch drilled bean field.

After we've counted the plants in the 3-foot plot and determined the average number of pods per plant, we multiply the number of plants in 3 foot by the average number of pods per plant to give us the number of pods in 3-foot of row.

To convert the number of pods in 3 foot or row to pods in a 3'X3' square, multiply the number of pods in 3-foot of row by 36 and divide by the row width.

It might look something like this:

(15 plants X 40 pods per plant) = 600 pods in 3 foot of row.

(600 pods X 36)/20 = 1,080 pods in a 3'X3' square.


... and in each field on Crop Tour. We've been doing it the same way since 1993...


You can collect samples from your farm the same way and participate in the Tour by going to our virtual crop tour and entering the data here.


Follow Pro Farmer Editor Chip Flory on Twitter: @ChipFlory

To see more of what Pro Farmer has to offer, be sure to visit

Log In or Sign Up to comment


No comments have been posted, be the first one to comment.
The Home Page of Agriculture
© 2014 Farm Journal, Inc. All Rights Reserved|Web site design and development by|Site Map|Privacy Policy|Terms & Conditions