ISHS Acta Horticulturae 810: IX International Vaccinium Symposium
ORGANIC PRODUCTION OF WILD BLUEBERRIES II. FERTILITY AND WEED MANAGEMENT |
| Authors: | J.M. Smagula, D.E. Yarborough, F. Drummond, S. Annis |
| Keywords: | Vaccinium angustifolium, sulfur, lowbush blueberry, pruning, organic fertilizer |
| Abstract:
A replicated field experiment was conducted from 2004 to 2007 to assess the main and interactive effects of pruning method, sulfur application, and fertilization on fertility and weeds in an organic lowbush blueberry field managed for 2 two-year production cycles in Amherst, Maine, USA. Within each of the split-plots of pruning (burning or mowing) and sulfur (at 1120 kg S/ha), an organic fertilizer Pro-Holly, (4-6-4) was applied preemergent at 0, 22, or 45 kg N/ha to 2 m x 15 m treatment plots in 2004 and 2006. Effects of treatments on soil and leaf nutrient concentrations and stem characteristics were determined. Weeds were cut using a motorized weed cutter once a month in June, July and August, 2004 and 2006. Grass, broadleaf, and woody weed cover were assessed each time prior to the sites being cut. Berry yield was determined by mechanically harvesting a 0.6 m wide strip down the middle of each plot in August 2005 and 2007. Sulfur lowered the soil pH each subsequent year resulting in a pH differential of 0.7 units by July 2007. Leaf N and P concentrations were not affected by sulfur or prune method, but were increased in plots with the highest rate of fertilizer compared to control plots after the second prune-year application. Mowed treatments had significantly higher grass and broadleaf weed cover than burned treatments in 2006. Plots treated with sulfur had significantly less grass and broadleaf weed cover than the untreated plots. Plots treated with 45 kg N/ha of fertilizer had significantly higher grass and broadleaf cover than those left untreated, but this did not reduce yield. Burned plots had higher yield than mowed plots in 2005 and 2007. Sulfur increased yield only in 2007. When pruned by fire, plots in sulfur-treated areas had the highest yield, almost twice that of plots in areas not receiving sulfur. | |
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