Plot Size Makes a Difference

Eric Tedford, technical lead for fungicides, Syngenta, uncovers a border and alleys effect with smaller field trial plots.

Eric Tedford
Eric Tedford
Eric Tedford, Ph.D., (left) had a mystery on his hands. In large commercial field trials, Quilt Xcel® fungicide increased yields by 10 to 15 bushels per acre; however, in smaller plots, like those commonly used in university trials, the results were quite different, with researchers seeing increases of only 1 or 2 bushels per acre.

To solve this conundrum, Tedford, technical product lead for fungicides at Syngenta, conducted a number of trials from 2009 to 2013. His research uncovered a “borders and alley” effect, which showed that the larger gaps between corn rows in small plot trials make a big difference in the results.

“Small-plot trial work on fungicides provides very meaningful results in terms of efficacy against diseases and even yield benefits when disease pressure is high,” says Tedford. “However, when disease pressure is low, they misrepresent grower-relevant yield benefits from fungicides. In those incidences, the borders and alley effect can cause different yield results than what growers might expect in their fields.”