Best management practices for organic blackcurrant production
K. L. Nelson and A. M. Hammermeister
Abstract
Organic producers in Prince Edward Island are growing blackcurrants (Ribes nigrum L.) to diversify their operations and supply domestic and international markets. The organic management of weeds, fertility and diseases has not been well established.
In 2009 trials were initiated at two sites previously planted in 2008 to examine the impacts of six treatments: (i) no fertility or weed control (Control); (ii) weed control only (Wonly); (iii) weed control + spring fertility (W+S); (iv) summer only (W+F); (v) spring and summer (W+SF); and (vi) weed control + fish fertilizer drench (W+D). In 2010, a disease management treatment was superimposed to create a split-plot design with disease control as the main plot (i.e. with or without sulphur spray) and three replicates of each fertility/weed control treatment as subplots. Fertility was supplied from a mixture (50:50, based on N content) of crabmeal (7% Ntot) and commercially available granulated poultry manure (4-1-2).
Weeds were controlled using a 1m strip of black polyethylene plastic. A foliar sulphur spray was applied to half of the plants to assess its effects on the plants and disease. The disease of greatest prominence was white pine blister rust, with 90% leaf infection on most plants at both sites. The efficacy of the sulphur treatment was very low, and the treatment reduced plant growth at one site. In 2009 growth in the Control was significantly lower than in the Wonly and W+fertility treatments at site two. A significant fertility response was not observed until 2010 at the second site where W+SF significantly increased bush growth compared with the Wonly and Control treatments.
Weed control significantly increased leaf tissue N content in 2009. Berry production was limited at one site due to the severity of disease; therefore berry analysis was restricted to one site. There was no interactive effect of disease control and treatment on the berry parameters, but there were treatment effects. Yield, hundred berry weight and Brix were significantly lower for the Control treatment. The use of fertility amendments again demonstrated a trend towards increased berry yields with a significant difference between the Wonly and W+SF.
Under severe disease stress, plants with weed control and a long-term fertility management plan performed better than without management.
Source
Plant Canada Conference. Saint Mary's University, Halifax, NS. July 17-21, 2011
Author Locations and Affiliations
Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada B2N 5E3
Posted May 2012