Project Number: 5310-12130-008-02
Project Type: Reimbursable

Start Date: Feb 01, 2006
End Date: Jan 31, 2007

Objective:
The goal of the project is the development and demonstration of simple, low-cost, and accurate methodology that can be used in place of currently mandated approaches to obtain emissions estimates. The methodology will be applied to current strawberry fumigation practices and to new reduced-emission strategies. This will enable the benefit of adopting emission-reduction methods to be identified and evaluated. The goal will be accomplished by conducting a systematic study of various methods to obtain emission rates and show that these methods effectively provide the same information when applied to 6-12 hour intervals. This leads to the following specific objectives for this study: (a) to test several low-cost approaches to measure reduction of emissions from soil fumigation that could help guide regulation, (b) to obtain information needed to support the use of the new methodology, and (c) to compare results from low-cost approaches to the currently accepted large-scale field studies (the large-scale studies will be conducted by others).

Approach:
Laboratory experiments will be conducted in a manner that closely represents actual field experimental conditions and that comparisons can be made to existing information on MeBr. Approximately 4 experimental configurations will be considered, including a mix of: Shank and drip injections, high-density polyethylene (HDPE) covers, thiosulfate seals, and impermeable films. For broadcast shank injections, a cylindrical column will be used to measure emissions, since fumigant movement is predominately in a single direction. For drip or bed-furrow injections, a rectangular box device will be used. Both allow the emissions to be automatically sampled by gas chromatography (GC). Experiments will be conducted using soils collected from the same fields used by the collaborators to obtain their field-scale emission rates using the ambient flux method. Emission measurements will continue until the concentrations are below detectable levels, generally from 1-3 weeks, and will be conducted in controlled temperature environments. Laboratory soil columns will be used to evaluate fumigant emission for traditional and reduced-emission scenarios. An automated enclosed column system will be used. Soil gas concentration data will be collected daily at the start of the experiment and at lengthening intervals as time elapses to a maximum period between sampling of 5 days, at the end of the experiment. A brief description of the methodology used to obtain some other basic information is given below. Documents Trust with CA Strawberry Commission. Log 30181. Formerly 5310-12130-007-04R (JUL 07).