Fertility and Weed Management in Organic Highbush Blueberry Production

The Nova Scotia highbush blueberry industry, because of the late season harvest, commands a significant niche on the N. American fresh market, with additional export markets for fresh and frozen product in Europe. Organic highbush blueberry production is recognized as a significant market opportunity for the industry both in Nova Scotia and in the US and Europe, with buyers in these markets regularly requesting certified organic product.

A significant hurdle to cost effective organic highbush blueberry management, however, is the labour costs associated with in-row weed control. Thick mulches in-row can provide weed suppression, improved soil tilth and water holding capacity, reduced temperature fluctuations, improved root distribution, and if well formulated, slow-release N. Commonly used mulches include weathered sawdust, wood chips, chipped brush or acidic peat moss.

Difficulties in estimating N availability under mulched systems using composts, has led to over fertilization in some organically managed highbush blueberry systems, however, with deleterious impacts on crop yield and quality. Few studies have examined in an integrated manner, weed pressure, and efficiency of crop N use, when diverse organic amendments are applied as a heavy mulch, under irrigated highbush blueberry production. The project, which will commence in 2005, has as its objectives:

1. To assess the use of PRSTM (anion/cation) membrane probes as an index of plant available N in highbush blueberry production, and as a decision support tool for determining split N applications.
   
   
2. To evaluate the benefits with respect to efficiency of crop N use, reduced leached N losses, and weed management, of a range of in row organic amendments/mulches (including commercial and on-farm composts, pelletized poultry manure, and sawdust, alone or combined in mixtures) when compared with standard inorganic N fertilizer (ammonium sulphate) application.

Researchers
Derek Lynch, OACC, Dept. Plant and Animal Sciences, NSAC
David Percival, Department of Environmental Science, NSAC
Nicole Burkhard, OACC, Dept. Plant and Animal Sciences, NSAC (Graduate Student)

Collaborators
Nova-Agri Associates., (Dykeview Farms), Centreville, NS
Envirem Technologies Inc., Fredericton, NB

Funding Sources
Nova Scotia Department of Agriculture & Fisheries
Envirem Technologies Inc., Fredericton, NB
Natural Sciences and Engineering Research Council (NSERC), Industrial Postgraduate Scholarship (IPS) Program.

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