Potato chemicals

Washington State University graduate student Colton Thurgood presents his findings on additive products Jan. 22 during the Washington-Oregon Potato Conference in Kennewick, Wash.

KENNEWICK, Wash. — Thirty-two products that are supposed to boost potato yields showed little actual benefit during a Washington State University study of non-traditional additives.

No clear justifications were found to support the use of the non-traditional additives, said Colton Thurgood, a WSU graduate student, during his Jan. 22 presentation at the Washington-Oregon Potato Conference in Kennewick, Wash.

Thurgood studies under WSU potato specialist Mark Pavek.

“That said, there also wasn’t anything showing that it would hurt,” Thurgood added. “If a grower is bent on using a product, I can’t say it’s going to hurt them, I can’t say it’s going to help them.”

A non-traditional additive is anything put on the crop in addition to standard fertilizers or pesticides, such as bio-stimulants, microbial inoculants, some speciality fertilizers, surfactants and humic acids.

The industry is full of such products, said Chris Voigt, executive director of the Washington Potato Commission.

“A lot of these products are coming from smaller companies that might not necessarily have robust research budgets,” Voigt said. “What we wanted to do is really create some objective data that growers can look at, to see if some of these products work and have the potential to increase yield or quality. There’s a whole bunch of claims out there, but not necessarily a lot of research backing them.”

Potato growers invested in the study because many use such products, Voigt said. Some swear by them, while others might not be convinced.

“I took a look at as many products as we could. We couldn’t do them all — there’s too many,” Thurgood said.

A 2004 estimate found more than 700 products, he said, adding that there are probably more now.

Thurgood wanted to get a representative look at how the products perform when added to standard practices, evaluating them for higher yields or economic returns. The study hasn’t shown any benefits, so far.

A few products showed small differences. With a few more years of research, they may prove profitable, he said.

The 32 products were donated by the manufacturers for the study, Thurgood said.

Thurgood’s results may not apply to all growing regions or conditions, but provide a good idea of their efficacy in the Pacific Northwest, he said.

Sometimes growers use the products as partial replacements for their standard fertilizer program, or monitor them so closely that they realize they can reduce water or fertilizer because they’re using a product, Thurgood said.

Thurgood talked about the amount of time and work it took for him to study the 32 products.

“If you wanted to do 100 products, it would be an enormous trial,” he said. “It’s just a matter of resources.”

But Thurgood believes any grower practice should be studied by a third party who doesn’t have a financial interest in how a product performs, to provide an unbiased look.

Thurgood and the commission checked with the manufacturers to ensure the products were used correctly or relied on label instructions, Voigt said.

Clear label recommendations for specific growing regions are lacking, Thurgood said.

It’s good data to share with growers, Voigt said, but the commission and researchers could further the research by working with the companies more closely.

“We can’t look super close at all 32, but are there a handful of them that we’re interested in?” he said.

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