It's going to be a soggy first day on the western leg of the 2015 Pro Farmer Midwest Crop Tour as scouts make their way from Sioux Falls, South Dakota, to Grand Island, Nebraska. Heavy rains diverted a few Sioux Falls-bound flights to Sioux City, Iowa, but most of the scouts have arrived and are ready to roll. More than 50 scouts will be with us on the western leg of the tour.
We're running 10 routes again on the western leg of the Tour, but we've got 16 drivers moving scouts to Grand Island. These are the same 10 routes we've run for several years - that's part of the consistency of the Tour. We do not, however, preselect fields to sample. Field and plot selection is left up to the scout teams that stop every 15 to 20 miles on their route - that's part of the randomness of the Tour.
Once a field has been selected, scouts will walk past the end rows, and then go 35 paces into the main rows of the field before laying out two 30-foot plots. Scouts will count all the ears that will make grain in the two rows, and record the tally. Scouts will also pull three ears from each field; the 5th, 8th and 11th ear from one of the 30-foot rows. That's consistency and randomness in one step of the sampling process. By selecting the 5th, 8th and 11th ear from one row of the plot, we could end up with the three best ears in the row, the three worst ears or three very average ears from the row. That's an important part of the process because it removes any bias the scout might have.
On the sample ears, we measure the length of grain on each ear in inches... we don't measure bare cob or aborted kernels, just the length of viable kernels. We also count the number of kernel rows around each ear. Along with the row width in the field, the data driving the yield calculation is the ear population, the average grain length and the average number of kernel rows around the ear. The yield calculation we use: Average ear population in 30-foot of row TIMES the average grain length TIMES the average number of kernel rows DIVIDED BY the row width in the field.
In soybean fields, scouts go to a "representative" spot in the field without cutting a path through the field. We then measure a 3-foot plot and count all the plants in the 3-foot plot. Three plants are then selected at random and we count all the pods that measure at least 1/4 inch on the three plants and calculate the average number of pods per plant. We then calculate the number of pods in the 3-foot plot by multiplying the average number of pods per plant by the number of plants in the 3-foot plot. To calculate the number of pods in a 3'X3' square, it's the number of pods in 3-foot TIMES 36 and DIVIDED BY the row space. This gives us the ability to compare soybean fields regardless of row width.
As tweets, reports and conversations start to flow from the Crop Tour, please keep in mind you're reading reports from 1 of the 10 western routes or 1 of the 12 eastern routes. What the other routes are seeing might, and very likely will, be different than what other routes are seeing. We will do our best to get the information out as soon as we can each evening, and waiting for the full results from each state is the safest way to get perspective from the Tour. If you're following the Tour on Twitter, just search for #pftour15.
Also, the Tour results should not be compared to USDA yield estimates in each state. We do things differently than does USDA, so the results should be expected to be different. Each night, Brian Grete, leader of the eastern leg of the Tour, and I will provide the perspective to allow you to compare this year's Tour results to last year's results and to the three-year average for each state. If you must compare it to the USDA data, do it on a percentage basis.
I'll check in with you guys tomorrow night from Grand Island. We'll have the final results from South Dakota and will give you some perspectives on corn and soybean yield potential in northeastern Nebraska.