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Is that Extra Fertilizer Worth It?

Posted by cahnrs.webteam | November 7, 2014

Maybe Not, Research Says

by Kathy Barnard, CAHNRS Marketing & News Services

While extra applications of nitrogen and other fertilizers might increase the overall yield in a potato field, it may not result in the optimal economic yield, according to research by WSU Extension horticulturist Mark Pavek and former graduate studentChris Hiles.

Chris Hiles presents the results of his research at the 2009 WSU Potato Field Day

Working with two newly released cultivars called Alturas and Premier at the WSU potato research unit in Othello, Hiles analyzed the impact of different nitrogen applications on crop yields. He also looked at overall economic yields as well. What he found may alter how growers approach adding inputs.

“Total yield doesn’t necessarily equate with the best economic yield,” he told those attending the WSU Potato Research Field Day in late June.

Especially given the increasingly high costs of petroleum-based fertilizers, optimal economic yield for the Premier cultivar actually occurs at approximately 87 percent of what is considered normal for growing Russet Burbank and maximum economic yield occurs at 96 percent of the normal rate for Russet Burbank in Alturas.

In other words, the net profit of a slightly smaller crop grown with fewer inputs is higher than a larger crop grown with inputs generally prescribed.

“There really is no reason to go above the 100 percent of normal rate,” Hiles said, “and in fact, the economics are better at lower levels.”

This article originally appeared in the July 22, 2009 edition of On Solid Ground.

More information

Graduate degree programs in Horticulture and Landscape Architecture at WSU