Improved growth and harvestable yield through optimization of fertilizer rates of soil-applied nitrogen, phosphorus, and potassium in wild blueberry (Vaccinium angustifolium ait.)

Abstract

The study examined the main and interactive effects of soil-applied fertilizers [nitrogen (N), phosphorus (P), and potassium (K)] from a 12-year (six production cycles) field experiment conducted at Kemptown, Nova Scotia (Canada). It also recommends the optimum rate for improved growth and harvestable yield of wild blueberry (Vaccinium angustifolium Ait.). The fertilizers were applied in a single application at the onset of shoot emergence in early spring of each sprout year at rates of 0, 12, 30, 48, and 60 kg·ha-1 N using urea (2000 only) or ammonium sulfate, 0, 18, 45, 78, and 90 kg·ha-1 P using triple super phosphate, 0, 12, 30, 48, and 60 kg·ha-1 K using potassium chloride. Response surface analysis of the data indicated that 35 kg·ha-1 N, 40 kg·ha-1 P, and 30 kg·ha-1 K were optimum for fruit production and maintaining stem lengths <20 cm, and resulted in an average of 54% more floral buds, 25% more berries per stem, and 13% greater yield than previous recommend rates of 20 kg·ha-1 N, 10 kg·ha-1 P, and 15 kg·ha-1 K. The higher fertilizers rates cost an extra $80/ha but increased net profits by $490/ha. Findings of this study could contribute toward better farm profitability in areas with similar growing conditions. They also suggest that modifications to existing fertilizer rates be made for Central Nova Scotia wild blueberry.