Research Associate Washington State University Pullman, Washington
Agricultural research is typically advantageous to growers, however, without the application of economics, the results are often misinterpreted, especially when the quantities of production inputs such as fertilizer, plant population, or seed size, are altered. Use of economics in evaluation of potato field trials allows researchers to combine all tuber yield and quality parameters into one ranking value that is well understood by the grower community. Moreover, utilizing regression analyses to model the economic findings allows for powerful, clear messages to the industry regarding treatments effects because the researcher is better able to predict and understand the relationships between multiple levels of treatments, rather than relying on individual treatment means comparison, which occurs when solely utilizing analysis of variance. For the past 25 years, multiple studies conducted by the Washington State University Potato Research Group (WSU) demonstrate the benefits of using the combined economic/regression analyses in identification of cultural management practices proven to boost and/or prevent the loss of potential grower income, especially when treatments that produce the highest yields fail to maximize economic return. As examples, fertilizer rate, seed size, and plant population research clearly demonstrate the usefulness of economic and regression analyses: beyond the economically optimum yield, marginal revenue gains from additional inputs are often offset by the increasing expense of those inputs, leading to an overall reduction in grower return. Specific discoveries serve as prime examples of the combined analyses: In 2018, WSU demonstrated that input and land-use efficiency improved significantly by reducing row width 2 inches; grower return also improved 5%; updated seed size recommendations in 2024 found that growers could improve seed-costed adjusted gross return by 2-3% over recommendations created in the 1980s. Ag researchers are encouraged to utilize economics and regression analyses when interpreting research results and presenting their findings to the grower community.
