DEHYDRATOR ONION YIELD RESPONSE TO BIOSTIMULANTS VARIES BY PRODUCT, RATE, AND ONION DEVELOPMENT STAGE
Horticulture & Turfgrass
Michael Rethwisch
Farm Advisor - Crop Production and Entomology
University of California Cooperative Extension
Blythe
Abstract
Dehydrator onions continue to increase in acreage in the California low desert area, in part due to water availability and drier production conditions which limit fungal diseases. As drought conditions in the western US continue to increase, increasing crop production without increasing water usage has continued to gain importance. Various biostimulant products were evaluated over a three year period to document their ability to increase yields. Several products were applied prior to germination and/or at emergence in combination with their additional application post emergence. Another group of products were applied only to foliage, with most treatments initiated at the third leaf stage. This latter set of products were applied twice (3rd and 5th green leaf) in 2020 and 2021, and also compared with three applications in 2021 (3rd, 5th and 7th green leaf), although a few products were only applied once. Number of replicates ranged from 4-6, depending upon the year. Trials were also conducted using two different varieties and utilizing different soil types to ascertain consistency of results. Yield results provided an range of responses. Guarantee Complex was most effective when used as a single application at germination/emergence, with additonal applications usually having little to negative effects on yields, The opposite was true for Liquid Seaweed Concentrate. Yield for foliar only applied products also indicated a range of responses. Yield response by treatment was very similar for 2020-2021, providing a high level of confidence in results. Best average yields were noted from a single application of 20 oz./acre of Vitazyme or two applications of CytoPower, both of which resulted in approximately 5+% yield increases.
Authors: Michael Rethwisch
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Michael Rethwisch Farm Advisor - Crop Production and Entomology, University of California Cooperative Extension - Riverside County, California, 92225-1649