Specialist like Purdue University's Bob Nielsen have talked for years about the need to have a check strip of some sort in your field when you try a new practice. A replicated plot is best, but if you can't do that, at least leave one strip somewhere so you know if the practice appeared to help at all or not. Otherwise, you're guessing in the dark as to whether a $10 to $30 an acre treatment paid off?
Greg Kneubuhler, of G & K Concepts, a crop consulting business, Harlan, Ind. Cites a recent example that proved the point. One of his clients had a cornfield where he applied fungicides with ground equipment, not aerially. Kneubuhler had recommended the application because the field was showing significant signs of disease when it was time to either make or not make the application.
The farmer wasn't crazy about spending the money, but he did, applying the fungicide on the fields where directed by the consultant to do so.
This summer, imaging maps taken from an airplane clearly showed the pass and a half where no fungicide was applied. GPS and aerial coordinates make pinpointing it easy to follow. "The strip was obvious," Kneubuhler says.
When the farmer harvested the plot last week, the result was more striking than the consultant expected. Untreated corn made about 160 bushels per acre. The treated corn made about 190 bushels per acre. Without a check strip, there would have been no way to know for sure if the treatment actually paid or not. Without a strip test, you get primarily visual observations.
Truth is, the consultant notes, that this was a rare case since the diseased plants were hit early and hit hard with both northern corn leaf blight and gray leaf spot. He's glad the farmer decided to treat. Obviously, the hybrid was also susceptible to the diseases.
"What we've found is that you really need to talk to plant breeders or agronomists to know what is susceptible and what isn't," he notes. For whatever reason, some information salesmen have, depending upon the company, isn't always accurate enough to help you make good decisions he says.
The farmer made a wise investment, but he only knows it know because he left a strip. While he took a yield hit on that strip, he gained valuable information that may help him make better decisions in the future.