ISHS Acta Horticulturae 574: VII International Symposium on Vaccinium Culture
CORRECTING LOWBUSH BLUEBERRY BORON DEFICIENCY WITH SOIL OR FOLIAR APPLICATION |
| Authors: | J.M. Smagula, W. Litten |
| Keywords: | Vaccinium angustifolium, boron leaf standard, DAP, MAP, sodium borate |
| Abstract:
In the acid podzol soils of Maine where most lowbush blueberries (Vaccinium angustifolium Ait.) are grown, low availability of boron tends to keep foliar B concentration below the 24 ppm standard. To compare efficacy of soil and foliar boron application methods, 1.5 x 7.6 m treatment plots in a commercial lowbush blueberry field received soil-applied borate at 0, 1.1, 2.2, or 3.3 kg B/ha with or without additional DAP (89 kg P/ha) and ZnSO4 (3.3 kg Zn/ha) or received foliar-applied Solubor at 0, 0.24, 0.49, or 0.74 kg B/ha with or without the additional DAP and Zn. These 16 treatments were replicated 8 times in a randomized complete block design. Leaf B concentrations were raised by all soil-applied borate treatments and by the 0.49 and 0.74 kg B/ha foliar Solubor treatments, compared to the controls. When borate at 2.2 or 3.3 kg B/ha was combined with DAP plus Zn a lower leaf B concentration was observed compared to B alone, possibly due to a dilution effect caused by an increase in DAP-induced growth. Leaf P deficiency (<0.125%P) was corrected when DAP and Zn were included in the fertilizer treatment. The greatest potential yield (flower buds/ stem and flower bud density) was measured in treatment plots receiving a combination of DAP plus Zn and either borate at 2.2 kg B/ha or Solubor at 0.74 kg B/ha. With no additional treatments applied in 1999, leaf B concentrations were slightly higher in soil-treated and foliar-treated plots than in controls suggesting a small carry-over from 1997-applied boron. | |
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