Microbial changes associated with use of brassica cover crops in a strawberry production system

View the project final report

Commodities

• Fruits: berries (strawberries)

Practices

• Crop Production: application rate management, cover crops
• Education and Training: extension
• Pest Management: biological control, mulching - plastic, soil solarization
• Production Systems: organic agriculture
• Soil Management: organic matter, soil analysis, soil microbiology

Brassica spp. have the potential to reduce soilborne diseases of strawberries when grown as a summer cover crop. Certain brassica amendments are described as “biofumigants” because they produce volatile products from glucosinolates that are inhibitory to a range of microorganisms including nematodes, fungi and bacteria. When grown in rotation or as a cover crop, these brassica crops have provided an advantage for the subsequent crop either due to disease suppression or yield increases. Annual strawberry production systems could incorporate a brassica crop, since strawberries are uprooted every year, and the field is left fallow for 3-4 months. Currently, most strawberry producers in Arkansas fumigate with methyl bromide or methyl iodide for disease and weed suppression. Soilborne diseases that have been of concern are black root rot, crown rot, leather rot, red stele and Verticillium wilt. This research will be conducted as part of a larger study to develop a sustainable and less chemically dependent, annual production system. The research outlined will determine if strawberry soilborne diseases are suppressed and how the soil microflora is changed in response to summer brassica cover cropping. Microbial populations, including bacteria, fungi, actinomycetes, and pathogen levels, will be assessed. Determining the mechanism and associated microbial shifts by which Brassica spp. reduce soilborne pathogens will improve our understanding of the sustainability of this production system. In addition, brassica cover cropping should be more cost efficient, allowing limited-resource farmers to grow an on-site biofumigant crop to aid in disease suppression.