The 2012 ASHS Annual Conference

A long-term systems trial was established to evaluate management practices for organic production of northern highbush blueberry (Vaccinium corymbosum L.). The factorial experiment included two planting bed treatments (flat and raised beds), source and rate of fertilizer (feather meal and fish emulsion applied separately at a low, 29–57 kg·ha^-1 N, or high rate, 57–102 kg·ha^-1 N, depending on planting age), weed management (sawdust mulch, compost topped with sawdust mulch, or weed mat), and cultivar (‘Duke’ and ‘Liberty’). The planting was established in Oct. 2006 and was certified organic in 2008. Cumulative yield, over four fruiting seasons (2008–11) was 18% higher on raised beds than on flat ground. ‘Duke’ plants fertilized with feather meal had greater yield than those fertilized with fish emulsion, but yield of ‘Liberty’ was not affected by the source or rate of fertilizer applied. In both cultivars, fertilization with the high rate of fish emulsion (57 kg·ha^-1 N, 2007-09; 102 kg·ha^-1 N, 2010-11) increased fruit firmness and percent soluble solids, but reduced berry weight compared to the low rate of fish emulsion or the use of feather meal. Weed mat was the best option for weed management, while yard debris compost plus sawdust mulch resulted in the most weeds and the highest weed-control cost; yield however was similar between the two treatments and higher in two out of three years than when using sawdust mulch alone. Plants mulched with weed mat required additional irrigation to maintain the same soil water content as those mulched with sawdust or compost plus sawdust, especially when grown on raised beds. Growth and yield of the “best” treatment combinations have been similar to well-managed conventional production systems.