Start Date: Aug 13, 2010
End Date: Sep 30, 2012
Objective 1-accumulate fumigant emissions data from ambient air around three large fields treated by broadcast shank fumigation in Ventura County. The test system will use methods preferred by California Department of Pesticide Regulation (CDPR) for assessing potential chloropicrin and 1,3-dichloropropene emissions from field applications. Objective 2-Fumigant concentration changes and movement in soil profile will be monitored throughout the study. A total of four soil-gas sampling probes will be installed in each field: two at the shank line and two between shank lines. Objective 3-Soil samples for residual fumigants by the time of tarp-cutting will be collected for evaluation of fumigant fate. Soil water content and temperature will be measured in the soil samples to facilitate required concentration calculations. Objective 4-The mass transfer coefficient (MTC) will be determined for the TIF using the standardized method (Papiernik et al. 2001; Yates et al., 2008). This method uses static sealed cells, where fumigant vapor is spiked to one side of the film and the concentrations on both side of the film are monitored until equilibrium, or, in the case of very-low-permeability films, at least until valid regression curves can be estimated based on adequate sampling at various pre-determined intervals.