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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Production and Genetic Improvement Research Unit » Research » Publications at this Location » Publication #398796
Research Project: Water and Nutrient Management for Sustainable Production of Small Fruit and Nursery Crops

Location: Horticultural Crops Production and Genetic Improvement Research Unit

Title: Applying boron by fertigation or as a foliar fertilizer is more effective than soil applications in northern highbush blueberry

Author
item LEON-CHANG, DAVID P. - Oregon State University
item Bryla, David

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2024
Publication Date: 3/26/2024
Citation: Leon-Chang, D.P., Bryla, D.R. 2024. Applying boron by fertigation or as a foliar fertilizer is more effective than soil applications in northern highbush blueberry. HortScience. 59(5):565-570. https://doi.org/10.21273/HORTSCI17461-23.
DOI: https://doi.org/10.21273/HORTSCI17461-23

Interpretive Summary: Boron (B) is often deficient in many fruit crops, including blueberry. ARS researchers in Corvallis, Oregon investigated different methods of applying B to cultivated blueberries, including soil applications, foliar applications, and fertigation, which is the practice of applying liquid forms of fertilizer through the irrigation water. Work was conducted in a mature blueberry field irrigated by drip. Foliar applications of B was the most effective method for increasing the concentration of B in the leaves, roots, and fruit, followed by fertigation with B fertilizer. Soil application of B, on the other hand, was relatively ineffective and resulted in less sugar in the fruit than either fertigation or foliar applications. Findings from this work provides valuable new information for improving nutrient management in blueberry.

Technical Abstract: Boron is often deficient in many fruit crops, including blueberry (Vaccinium sp.). The objective of the present study was to evaluate different methods for applying B fertilizers to two commercial cultivars of northern highbush blueberry (V. corymbosum ‘Earliblue’ and ‘Aurora’) in western Oregon. Treatments included soil application of sodium tetraborate in early April (prior to bloom), foliar application of boric acid in late April (during petal fall or bloom), weekly fertigation with boric acid from April through July, and a control with no B. The plants were irrigated by drip and the fertilizers were applied for 2 years at a total rate of 1.5 kg/ha B per year. All treatments were also fertilized with 224 kg/ha N and 30 kg/ha P per year. Each method of fertilizer application increased the concentration of B in the soil solution relative to the control, but fertigation was the only treatment that increased extractable soil B to the recommended level of 0.5-1.0 mg/kg B. In terms of plant nutrition, foliar applications of B was the most effective method for increasing the concentration of B in the leaves, roots, and fruit, followed by fertigation with B. Soil application of B, on the other hand, was relatively ineffective and after 2 years only increased the concentration of B in the leaves of ‘Earliblue’. While leaf B levels were initially deficient at the site (< 30 ppm B), none of the B application methods had any effect on yield, berry weight, fruit firmness, or titratable acidity of the fruit in either cultivar. However, foliar applied B resulted in higher concentrations of soluble solids in the fruit than no B or soil applied B in ‘Earliblue’, and fertigation with B resulted in higher concentrations of soluble solids in the fruit than soil applied B in ‘Aurora’. Based on these results, applying B by fertigation or as a foliar spray is recommended over the use of soil applications of B fertilizer in northern highbush blueberry.