Nontraditional production additives fail to improve potato yield and economic return

Authors: THURGOOD, COLTON - Washington State University; Gonzalez-Tapia, Francisco - Paco; HOLDEN, ZACHARY - Washington State University; PAVEK, MARK - Washington State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2022
Publication Date: 11/20/2022
Citation: Thurgood, C., Gonzalez Tapia, F., Holden, Z., Pavek, M.J. 2022. Nontraditional production additives fail to improve potato yield and economic return. Agronomy Journal. Volume 115, Issue 2, Page 801-816. https://doi.org/10.1002/agj2.21259.
DOI: https://doi.org/10.1002/agj2.21259

Interpretive Summary: Manufacturers of nontraditional crop additives often claim their products will improve crop yield and soil health, yet many only offer grower testimonials for product validation. To investigate these claims in potatoes, we evaluated 32 nontraditional additive products. Treatments were applied using one or more application techniques: in-furrow, surface band, foliar broadcast, and through the irrigation system per manufacturer recommendations, and in addition to grower standard practices. The grower's gross return, which accounted for the cost of the product and application, ranged from -7.7% to 8.5%. Although some of the nontraditional products increased yields, these were not statistically significant from the controls. One of the products improved average tuber weight, and a second product increased tuber dry matter. It is worth noting that Washington State produces the highest potato yields worldwide, and thus, it is difficult for any yield improvements from additional inputs. In potato-growing regions with less favorable conditions, some of these products may prove beneficial for potato production.

Technical Abstract: Manufacturers of nontraditional crop additives often claim their products will enhance yield and improve economic return, yet many of the manufacturers only offer anecdotal evidence to support their claims. Consequently, many of these products may only serve to reduce grower return. To investigate these claims in potato, field trials were conducted near Othello, Washington from 2016 to 2019 on 27 nontraditional additive treatments comprised of 32 products. Treatments were applied using one or more application techniques: in-furrow, surface band, foliar broadcast, and/or through the irrigation system per manufacturer recommendations and in addition to grower standard practices. Conventional nutrients were applied to be non-limiting to potato growth. Economic return was calculated using a mock processing contract and adjusted for individual product costs that ranged from $15 to $889 ha-1. Treatment adjusted gross return values ranged from -7.7% to 8.5% of the grower standard treatment value, and total yields ranged from 108 to 136 Mg ha-1, but differences from the control were not significant for any treatment. Reclaim® OneUP® and NutriCal® increased US No. 1 yield, average tuber weight and tuber specific gravity, respectively. Some of the tested products may provide other benefits like soil health improvement or water use reduction but those parameters were outside the scope of this study. Unproven products should be avoided until studied by an unbiased research entity unless growers are comfortable performing randomized and replicated tests on their farms prior to large-scale application.