The impact of Brassica napus seed meal on the microbial complex that incites apple replant disease was evaluated in greenhouse trials. Regardless of glucosinolate content, seed meal amendment at a rate of 0.1% (vol/vol) significantly enhanced growth of apple and suppressed apple root infection by Rhizoctonia spp. and Pratylenchus penetrans. High glucosinolate B. napus cv. Dwarf Essex seed meal amendments did not consistently suppress soil populations of Pythium spp. or apple root infection by this pathogen. Application of a low glucosinolate containing B. napus seed meal at a rate of 1.0% (vol/vol) resulted in a significant increase in recovery of Pythium spp. from apple roots, and a corresponding reduction in apple seedling root biomass. When applied at lower rates, B. napus seed meal amendments enhanced populations of fluorescent Pseudomonas spp., but these bacteria were not recovered from soils amended with seed meal at a rate of 2% (vol/vol). Seed meal amendments resulted in increased soil populations of total bacteria and actinomycetes. B. napus cv. Dwarf Essex seed meal amendments were phytotoxic to apple when applied at a rate of 2% (vol/vol), and phytotoxicity was not diminished when planting was delayed for as long as 12 weeks after application. These findings suggest that B. napus seed meal amendments can be a useful tool in the management of apple replant disease and, in the case of Rhizoctonia spp., that disease control operates through mechanisms other than production of glucosinolate hydrolysis products.

Additional index words. orchard floor management, weed control, water conservation, soil quality, nitrogen Abstract. The semiarid climate of the Pacific Northwest allows for the production of organic, temperate tree fruit relatively free of disease and with fewer key insect pests compared with other regions of the United States. Weed control and soil fertility are two of the higher cost areas for organic tree fruit where alternatives are being sought through research and on-farm innovation. Mulches, both living [e.g., white clover [(Trifolium repens)] and inert (e.g., wood chips) show promise for controlling weeds, conserving water, providing nitrogen (N), or improving tree growth, but potentially have system trade-offs such as increased rodent pests and unwanted late-season N. Growers need orchard floor management practices that help them maintain or improve soil quality per the requirements of the National Organic Standards.

Alternative management strategies to the use of preplant soil fumigation for the control of apple replant disease (ARD), including cover crops and strategies incorporating Brassica napus seed meal (rape seed meal [RSM]) amendment as the central component, were evaluated in the orchard. A 1-year wheat cover crop consisting of three short-term cropping periods with plant material removed at the end of each growth period and a 3-year B. napus green manure significantly enhanced vegetative growth and yield of Gala/M26. However, in each instance, the resulting disease control and growth response were inferior to that achieved through preplant methyl bromide soil fumigation. A 3-year bare fallow and 1- or 2-year B. napus green manure neither suppressed disease development nor enhanced tree growth. Preplant RSM amendment in conjunction with a postplant mefenoxam soil drench provided effective suppression of ARD, and the resulting tree growth and yield were comparable with that attained in response to 1,3- dichloropropene-chloropicrin fumigation in one orchard. At a second orchard, the growth response attained with the alternative treatment was inferior to preplant soil fumigation, which was associated with an apparent re-infestation of RSM-treated soils and tree roots by Pratylenchus spp. Application of RSM after wheat cropping or in conjunction with soil solarization provided an intermediate level of disease control and a corresponding reduction in growth and yield of apple relative to preplant fumigation at both sites.

In the Greater Vancouver region (Canada) tensions exist where urbanization encroaches onto agricultural land. A recently issued white paper proffered ideas to stimulate discussion on land-use plans and public policies to encourage and enhance agriculture while accommodating a doubling of the region's population. It evoked a visceral response from local and regional politicians, planners and agrologists who saw it as an heretical attempt to undermine land conservation. Proponents saw innovative strategies to ameliorate entrenched antipathy between competing perspectives. The core arguments and corresponding critique, outlined in this paper, bring to light elements of a broader debate about the vitality and sustainability of agriculture in British Columbia, as elsewhere, centring on issues of food security (supply) and food sovereignty (control) within two competing agricultural paradigms: human-scale agri-food systems and conventional industrial agri-business. Municipal enabled agriculture (MEA) is advanced as a catalyst for the full integration of the agri-food system within the planning, design, function, economy and community of cities and vice versa. MEA can make significant contributions to local and regional economies and has the potential to alter the way communities are designed to reduce unsustainability, planned to incorporate resilience, and organized so that they flourish socially and culturally.