title: Emission and transport of 1,3-dichloropropene and chloropicrin in a large field tarped with VaporSafe TIF.
abstract: Tarping fumigated fields with low permeability films such as commercial Totally Impermeable Film (TIF) can significantly reduce emissions, but it can also increase fumigant residence time in the soil such that extended tarp-covering durations may be required to address potential exposure risks during tarp-cutting and removal. In an effort to develop safe practices for using TIF, a large field study was conducted in the San Joaquin Valley of California. Comprehensive data on emissions (measured with dynamic flux chambers), fate, and transport of 1,3-dichloropropene and chloropicrin were collected in a 3.3 ha field fumigated with Pic-Clor 60 via broadcast shank application. Low emission flux (below 15 μg m(-2) s(-1)) was observed from the tarped field throughout the tarp-covering period of 16 days with total emission loss of <8% of total applied for both chemicals. Although substantially higher flux was measured at tarp edges (up to 440 μg m(-2) s(-1)), the flux was reduced to below 0.5 μg m(-2) s(-1) beyond 2 m of tarp edge where total mass loss was estimated to be ≤ 1% of total applied to the field. Emission flux increased following tarp-cutting, but was much lower compared to 5 or 6 d tarp-covering periods determined in other fields. This study demonstrated the ability of TIF to significantly reduce fumigant emissions with supporting data on fumigant movement in soil. Proper management on use of the tarp, such as extending tarp-covering period, can reduce negative impact on the environment and help maintain the beneficial use of soil fumigants for agricultural productions.
authors.affiliation: USDA-ARS, Water Management Research, San Joaquin Valley Agricultural Sciences Center, Parlier, California 93648, United States. Gao@ars.usda.gov
authors.forename: Suduan
authors.initials: S
authors.lastname: Gao
authors.forename: Husein
authors.initials: H
authors.lastname: Ajwa
authors.forename: Ruijun
authors.initials: R
authors.lastname: Qin
authors.forename: Michael
authors.initials: M
authors.lastname: Stanghellini
authors.forename: David
authors.initials: D
authors.lastname: Sullivan
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D000498:Allyl Compounds / Q000032:analysis*; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D000498:Allyl Compounds; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D012989:Soil Pollutants; C023891:1,3-dichloro-1-propene; C100187:chloropicrin