Location: Horticultural Crops ResearchTitle: Response of blackberry cultivars to fertilizer source in an organic fresh market production system) Author
Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2014
Publication Date: 9/30/2014
Citation: Fernandez-Salvador, J., Strik, B.C., Bryla, D.R. 2014. Response of blackberry cultivars to fertilizer source in an organic fresh market production system. HortScience. 49(9):S277. Interpretive Summary:
Technical Abstract: One semi-erect (‘Triple Crown’) and three trailing (‘Marion’, ‘Black Diamond’, and ‘Obsidian’) blackberry cultivars were studied from 2011-12 at a certified organic, grower site in Jefferson, OR. Plants were fertilized with 56 kg/ha N each spring using: 1) a liquid fish and molasses blend; 2) pelletized soybean meal; or 3) pelletized, processed poultry litter. ‘Triple Crown’ produced the greatest yield in both years, whereas ‘Black Diamond’ and ‘Marion’ had the lowest yield in 2011 and 2012, respectively. ‘Triple Crown’ fruit had the highest % soluble solids and were the least firm in 2011, while ‘Marion’ fruit were the least firm in 2012. The effect of fertilizer source on yield and fruit quality was relatively small and was inconsistent among cultivars and years. Soy meal produced the greatest total yield in ‘Triple Crown’ in 2011 and in ‘Obsidian’ in both years. In contrast, poultry and fish produced the greatest total yield in ‘Black Diamond’ in 2011, and fish produced the greatest yield in ‘Black Diamond’ and ‘Marion’ in 2012. Fruit wt differed among the four cultivars, particularly when plants were fertilized with soy than with poultry or fish in 2011, but was not significantly different among the three fertilizers within each cultivar. Most soil nutrients were within the recommended range for all fertilizer treatments, except B, which declined to deficient levels in the second year. Fertilizer source had no effect on soil nutrient levels other than fertilization with fish increased soil K and Na. Primocane leaf tissue nutrient concentrations were above or within recommended standards for most nutrients, except for Mg, Ca, and B, which, depending on cultivar, were below standards. Over the 2-year study, the cultivars responded similarly to the three sources of organic fertilizer. However, the cost per kg N varied from $18.00 for the fish and molasses blend, $11.80 for the soybean meal, and $5.60 for the poultry litter. Supplemental fertilization with B, Mg, and Ca would be required with each fertilizer to maintain recommended soil fertility levels.