Since 2016, DIFM has worked with hundreds of farmers on three continents and in over twenty U.S. states, running on-farm precision experiments (OFPEs) to examine the effects changing fertilization, planting, and other input application rates on the yield and protein outputs of numerous crops, including corn, wheat, barley, canola, soybeans and cotton.  The figure below presents an example of an OFPE “trial design” that was implemented on a 71-acre Ohio, USA field in 2022.  (The entire report sent to the farmer (with all identifying names redacted) can be found here.)  The farmer’s “status quo” application strategy (that is, the one the farmer would have used had there been no field trial conducted) was to apply a base N rate of 5 lbs uniformly across the field, then to follow that up with rate of 48 gallons/ac of UAN28/ATS, which in total would apply an N-equivalent of 5 + 48*2.822 = 140 lbs/ac. The status quo rate was assigned to a buffer zone around the perimeter of the trial, but observations from the buffer zone were not included as part of the trial in later analysis. The trial design’s targeted total UAN28/ATS and N-equivalent rates were 15, 33, 48, 69, and 86 gallons (47, 98, 140, 200, and 248 lbs)per acre.

The farmer was able to implement the trial design on his field by uploading the trial design “prescription” as a shapefile into his variable-rate applicator, and just driving.  That is, putting this trial in the ground was no more difficult for him than was his usual practice of applying N variably across his field using a commercial variable rate application “prescription.”