Doug Alert and Margaret Smith (Hampton) grow soybeans once in their five-year rotation. They wondered whether under those conditions there is a significant benefit to inoculating soybean seed with a fresh dose of the Rhizobia bacteria that fix nitrogen for the crop. But the term “significant” can mean different things. In research, statistical significance means a result that would be unlikely to occur by chance. In PFI trials, “unlikely to occur by chance” typically means an outcome that would occur less than 5 percent of the time even if the treatments had no effect. By that definition of “significant,” soybean inoculant didn’t quite improve yield. There is roughly a 7 percent chance that the 0.6-bushel yield difference was a random occurrence given our assumptions. Most agricultural researchers would say this yield difference is at least great enough to merit another trial. But if you define significant as “meaningful or important,” six-tenths of a bushel doesn’t make it for Doug. He probably will not take the trouble to inoculate soybeans in the future.
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