Response of ‘Bluecrop’ Highbush Blueberry to Boron Fertilization

Abstract

ABSTRACT The objective of this experiment was to examine the vegetative and generative responses of highbush blueberry to boron fertilization. The study was carried out in 2002–2003 in Central Poland on mature ‘Bluecrop’ blueberries (Vaccinium corymbosum L.) planted at a spacing of 3 × 1 m on a sandy loam soil with pH value of 3.9 and low hot water soluble boron status. Blueberries were soil- or foliar-supplied with boron. Foliar boron sprays were done four times per season: at the beginning of blooming, at petal fall, and three and six weeks after the ending of flowering. In each spray treatment, boron was applied at a rate of 0.2 kg ha−1. Soil boron was applied at the stage of bud break at a rate of 2 kg ha−1. Plants untreated with boron served as control. The results showed that boron fertilization increased boron levels in flower and leaf tissues. This treatment, regardless of boron application mode, did not affect plant vigor, the number of flowers per cane, fruit set, nor yield. Also mean fruit weight and berry firmness were not influenced by boron fertilization. Fruit of boron-supplied blueberries had higher soluble solids concentrations than those of the control plants. It is concluded that boron requirements of highbush blueberry are relatively low compared to most fruit crops and that critical leaf boron concentrations of ‘Bluecrop’ blueberry are below 15 mg kg−1 DW.