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.
Rizwan Maqbool, David Percival, Qamar Zaman, Tess Astatkie, Sina Adl and Deborah Buszard
Brian P. Pellerin, Deborah Buszard, David Iron, Charles G. Embree, Richard P. Marini, Douglas S. Nichols, Gerald H. Neilsen and Denise Neilsen
Tree fruit growers use chemical and mechanical thinning techniques in an attempt to maintain regular annual flower production and maximum repeatable yields of varieties susceptible to biennial bearing. If the percentage of floral buds an apple tree could produce without causing yield depression in subsequent years was known, it would be possible to better manage crop-thinning regimes. This study proposes that thinning is a partial transfer of potential flower buds from one year to the next year and estimates the maximum repeatable sequence of flower buds without biennial bearing. The conceptual framework is tested on a 50-year simulation with 0% to 100% transfer of thinned flower buds. Results indicate that the maximum repeatable sequence of flower buds rises sharply when the final years of the orchard approach and declines when the percent transfer of thinned buds is near 0%.