New Innovations in Production Technology and Off-season Marketing for Strawberries

Husein Ajwa - University of California, Davis
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Fumigants are regulated primarily based on air emissions. Reducing fumigant emissions into the atmosphere has become critical to ensure the continued availability of methyl bromide alternative fumigants. Current methods of soil fumigation can result in unintended fumigant escape into the atmosphere. Our goal was to develop management practices that can significantly reduce fumigation emissions while achieving good soil pest control. Our research evaluated the use of VIF, semi-impermeable film (SIF), and sprinkler-applied water plus thiosulfate seal to reduce volatilization losses of 1,3-dichloropropene (1,3-D) and chloropicrin (Pic) after drip application of these fumigants to raised soil beds. Experiments were conducted in the coastal strawberry production areas in California. Each experiment was conducted simultaneously on four adjacent fields. Each field was one acre, and the four fields were separated from each other by >1000 ft to avoid cross contamination. The four fields contained the same soil type, soil moisture, drip tape, and were prepared following standard strawberry field practices by cooperating growers. The four sealing treatments were: 1) standard high density polyethylene (HDPE), 2) standard HDPE plus 10 mm water seal containing 25 gal potassium thiosulfate, 3) VIF or SIF, and 4) VIF or SIF plus 10 mm water seal containing 25 gal potassium thiosulfate. A sprinkler system was used to apply the water plus thiosulfate seal immediately after drip fumigation with InLine or Pic. The Indirect Flux Method was used to estimate fumigant flux from the field. This method uses the Industrial Source Complex Short Term (ISCST3) model and an atmospheric dispersion model used by EPA for regulatory purposes. Fumigant flux was estimated by using the ISCST3 model. This presentation will discuss flux results for InLine applied under SIF plus thiosulfate. In addition, we compare fumigant emissions computed by using three techniques: 1) off-site indirect method, 2) closed chamber method, and 3) on-site micrometeorological method.

Other talks in this session: New Innovations in Production Technology and Off-season Marketing for Strawberries

1. Alexandra Wagstaffe: Tunnel Production in The United Kingdom
2. Fumiomi Takeda: Recent Strawberry Production Innovations in the Eastern United States
3. Husein Ajwa: Methods to Reduce Fumigant Volatilization Losses from Agricultural Fields
4. Kirk Larson: Hitting Off-season Market Windows in California
5. Tomohiro Yanagi: Japanese Greenhouse Production and Regulation Of Flowering Time