James W. Julian, Glenn H. Sullivan, and Stephen C. Weller
James W. Julian, Bernadine C. Strik, Handell O. Larco, David R. Bryla, and Dan M. Sullivan
A systems trial was established to evaluate factorial management practices for organic production of northern highbush blueberry (Vaccinium corymbosum L.). The practices included: flat and raised planting beds; feather meal and fish emulsion fertilizer applied at 29 and 57 kg·ha−1 of nitrogen (N); sawdust mulch, compost topped with sawdust mulch (compost + sawdust), or weed mat; and two cultivars, Duke and Liberty. The planting was established in Oct. 2006 and was certified organic in 2008. Weeds were managed by hand-hoeing or pulling in sawdust and weed mat-mulched plots and a combination of hand-pulling, propane-flaming, and post-emergent, targeted applications of acetic acid or lemon grass oil to any weeds present in the compost + sawdust plots depending on year. Data were recorded on input costs and returns in Year 0 (establishment year) through Year 3. Plants were harvested beginning the second year after planting. Planting costs were $741/ha higher on raised beds than on the flat, but the higher costs were more than offset by an average of 63% greater yields that improved net returns by as much as $2861/ha. Cumulative net returns after 3 years were negative and ranged from –$32,967 to –$50,352/ha when grown on raised beds and from –$34,320 to –$52,848/ha when grown on flat beds, depending on cultivar, mulch, and fertilizer rate and source. The greatest yields were obtained in plants fertilized with the low rate of fish emulsion or the high rate of feather meal, but fertilizing with fish emulsion by hand cost (materials and labor) as much as $5066/ha more than feather meal. Higher costs of establishment and pruning for ‘Liberty’ compared with ‘Duke’ were offset by higher net returns in all treatment combinations, except feather meal fertilizer with either weed mat or compost + sawdust mulch. Mulch type affected establishment costs, weed presence, and weed management costs, which included product and labor costs for application of herbicides (acetic acid and lemon grass oil) as well as labor for hand-weeding as needed, depending on the treatment. The highest yielding treatment combinations (growing on raised beds mulched with compost + sawdust and fertilized with fish emulsion) improved cumulative net returns as much as $19,333/ha over 3 years.