Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 10/5/2007
Publication Date: 11/1/2007
Citation: Gao, S., Qin, R., Mc Donald, J., Hanson, B.D., Trout, T.J. 2007. Field Tests on Emission Reduction Methods from Telone C35 Application. International Conference on Methyl Bromide Alternatives and Emissions Reductions. Interpretive Summary: Minimizing soil fumigant emissions is required to meet air-quality standards in California. To develop effective and economically feasible methods, this research tested various potential surface seal and soil treatments to minimize emissions of 1,3-Dichloropropene and Chloropicrin emissions from shank-injection of Telone C35 in a field trial in the San Joaquin Valley of California. An irrigation before fumigation (pre-irrigation) with sprinklers was more effective in reducing emissions than post-fumigation intermittent water seals. The most effective treatment was from an intermittent water seals containing potassium thiosulfate but showed some unknown reactions with soil. The pre-irrigation, which did not reduce fumigant concentrations in soil air, offers a favorable option in field practice because of its easy management and the least fumigant exposure risks to workers. An application of composted manure to soil surface followed by standard plastic tarp did not reduce emissions compared to the control indicating the need for further understanding of using organic amendment to achieve low emissions.
Technical Abstract: Telone or 1,3-dichloropropene (1,3-D) and chloropicrin (CP) are primary alternative soil fumigants to methyl bromide and, as volatile organic compounds (VOCs), their emission reductions are required to meet air-quality standards in California. This research tested various potential surface seal and soil treatments to minimize emissions of 1,3-D and CP from shank-injection of Telone C35 (61% 1,3-D and 35% CP) in a field trial conducted in October 2006 at Parlier in the San Joaquin Valley of California. Treatments included control, pre-irrigation (irrigation with sprinklers four days prior to fumigation), post-fumigation water seals (applied through irrigation with sprinklers following fumigant application) with or without potassium thiosulfate (KTS), and combinations of standard high density polyethylene (HDPE) tarp and amended surface soil with either composted manure or KTS. Air emissions and concentrations of fumigants in soil gas were monitored for two weeks. The intermittent KTS applications following fumigation is much more effective in reducing fumigant emissions compared to the intermittent water seals. The pre-irrigation was more effective to reduce emissions than the intermittent water seals although less effective than the KTS treatments. Fumigant distribution in soil gas was not affected in the pre-irrigated soils. The pre-irrigation offers a favorable option in field practice because of its easy management with no fumigant exposure risks to worker involved. The application of composted manure to soil followed by HDPE tarp after fumigation resulted in equal or even higher emissions than the control, which was suspected by the high soil temperature under that tarp causing fumigant desorption and subsequently high emission rates in day time. Further study is needed for better understanding on using organic amendment to minimize emissions from soil fumigation.