"Fungicide on wheat? Well that 's another $13 an acre," Carson states. "Let's see if it really works? If you get your money back?"

He first set up a field test using fungicides from three different manufacturers and three different varieties of wheat, leaving a check strip through each variety and each chemical.

Next, he took his field maps to his aerial applicator and instructed them to leave check strips 180-feet wide, "but, don't tell me where you left them. If I can't find them with the yield monitor in the combine, it's not worth it."

The results: Carson found out exactly where the check strips were when he harvested the crop with his combine and FIELDSTAR yield monitor.

"Where we didn't put on any fungicide, in the check strip areas, the wheat was going backward like crazy. When we harvested there was a 22-bu./acre difference in yield where we ran across our fungicide check with the combine.

Through advanced techniques like soil conductivity tests, Carson confirms the accuracy of his yield and topography maps.

"Without the yield monitor how would you know that fungicides works? Or, how well they work? There were even variations in yield where a slight drift had moved the fungicide into the check area."

Carson is convinced that you need a yield map to prove what you're doing - where you can cut back on crop inputs and where you can't.