Main and Interactive Effects of Vegetative-Year Applications of Nitrogen, Phosphorus, and Potassium Fertilizers on the Wild Blueberry

摘要

An experiment examining the main and interactive effects of vegetative (i.e., sprout) year applications of nitrogen, phosphorus, and potassium fertilizers was conducted at two commercial wild blueberry fields near Kemptown, Nova Scotia and Mount Vernon, Prince Edward Island during 2000 and 2001. The nitrogen (N), phosphorus (P), and potassium (K) sources consisted of urea (N at 0 to 60 kg centre dot ha~(-1)), triple superphosphate (P_2O_5 at 0 to 150 kg centre dot ha~(-1)), and potash (K_2O at 0 to 60 kg centre dot ha~(-1)). A completely randomized rotatable composite design was used with 16 treatments, 4 replications, a plot size of 6 m X 8 m, and 2 m buffers between plots. Overall, leaf tissue N, P, and K levels were increased at both sites with fertilizer applications. Main and interactive effects of the soil applied N, P, and K on stem length, individual stem dry weight, and stem density were also present at both sites. Significant effects of soil-applied N and K, and soil applied K on fruit set were present at the Kemptown and Mount Vernon sites with fruit set increasing up to 20% and 51%. respectively. Harvestable yield varied in response to the N-P-K treatments with no treatment having a significantly higher yield than the non-fertilized treatment at the Kemptown site, and the harvestable yield of the unfertilized treatment being as much as 36% lower than other soil-applied N-P-K treatments at the Mount Vernon site. Therefore, results from this study illustrate the importance of monitoringleaf tissue N, P, and K levels, the ability to alter leaf tissue N, P, and K levels and correct leaf tissue deficiencies, and the beneficial yield component effects of soil-applied N, P, and K when applied to the wild blueberry under nutrient deficientconditions.