Second cropping of wild blueberries — Effects of management practices

Wild blueberries (Vaccinium angustifolium Ait.) are normally managed on a biennial basis. Pruning forces the plant into a vegetative year without fruit, followed by the first crop year, which provides the greatest harvest. In subsequent years, harvest levels drop dramatically. Prior to the introduction of selective herbicides, second crop yields were too low to allow the adoption of a double harvest. This study was initiated to compare production and incomes of a single cropping (2-yr management cycle, the present system) versus a double cropping system (3-yr management cycle), using systems that include herbicides. Total yields and net incomes over the 12-yr study were affected by fertilizer applications, but not by management system (2-yr management cycle versus 3-yr management cycle) or pruning (burning versus mowing). Yields in second crop plots were lower than those in first crop plots, even though blossom numbers were higher. Fertilizer affected many aspects of blueberry plant development, including stem length, numbers of buds and blossoms, and fruit yields. Over time, yields and net incomes in the 3-yr management cycle were similar to those for the standard 2-yr management cycle. Key words: Vaccinium angustifolium, 3-yr management, net income, fertilization, pruning