Biofumigation for soil health in organic high tunnel and conventional field vegetable production systems

View the project final report

• 2006 annual report
• 2007 annual report
• 2008 annual report
• 2009 annual report

Commodities

• Agronomic: canola
• Vegetables: beets, cabbages, carrots, cucurbits, greens (leafy), onions, peppers, tomatoes

Practices

• Crop Production: continuous cropping, cover crops, organic fertilizers
• Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research
• Farm Business Management: whole farm planning
• Pest Management: allelopathy, biological control, botanical pesticides, integrated pest management, mulches - killed, mulching - plastic, soil solarization, mulching - vegetative
• Production Systems: holistic management
• Soil Management: green manures, organic matter, soil analysis, soil quality/health

Biofumigation and solarization were tested as possible organic controls of white mold (Sclerotinia sclerotiorum), a soil-borne pathogen of cool-season vegetable crops commonly found in high tunnels. Biofumigation was also tested as a possible control of the warm season vegetable pathogen Phytophthora capsici. Pacific Gold mustard was identified as a potential biofumigant crop with a combination of high biomass production and glucosinolate concentration. Laboratory studies showed both pathogens to be susceptible to glucosinolates extracted from the mustard, but soil incorporation of field-grown biomass did not introduce sufficient glucosinolate to reduce disease pressure. Summer solarization in high tunnels destroyed white mold sclerotia.

1. Identify brassica varieties that inhibit survival and growth of S. sclerotiorum and P. capsici in lab-based bioassays. Determine the potential of brassica residue incorporation and solarization – alone and in combination – to reduce disease pressure from S. sclerotiorum and build biologically active soils in high tunnels used for year-round vegetable production. Determine the potential for brassica and non-brassica cover crops to reduce disease pressure from P. capsici and build biologically active soils in field vegetable production systems.