title: Surface seals reduce 1,3-dichloropropene and chloropicrin emissions in field tests.
abstract: Reducing emissions is essential for minimizing the impact of soil fumigation on the environment. Water application to the soil surface (or water seal) has been demonstrated to reduce 1,3-dichloropropene (1,3-D) emissions in soil column tests. This study determined the effectiveness of water application to reduce emissions of 1,3-D and chloropicrin (CP) in comparison to other surface seals under field conditions. In a small-plot field trial on a Hanford sandy loam soil (coarse-loamy, mixed, superactive, nonacid, thermic Typic Xerorthents) in the San Joaquin Valley, CA. Telone C35 (61% 1,3-D and 35% CP) was shank-applied at a depth of 46 cm at a rate of 610 kg ha-1. Soil surface seal treatments included control (no tarp and no water application), standard high density polyethylene (HDPE) tarp over dry and pre-irrigated soil, virtually impermeable film (VIF) tarp, initial water application by sprinklers immediately following fumigation, and intermittent water applications after fumigation. The atmospheric emissions and gas-phase distribution of fumigants in soil profile were monitored for 9 d. Among the surface seals, VIF and HDPE tarp over dry soil resulted in the lowest and the highest total emission losses, respectively. Intermittent water applications reduced 1,3-D and CP emissions significantly more than HDPE tarp alone. The initial water application also reduced emission peak and delayed emission time. Pre-irrigated soil plus HDPE tarp reduced fumigant emissions similarly as the intermittent water applications and also yielded the highest surface soil temperature, which may improve overall soil pest control.
authors.affiliation: USDA-ARS, Water Management Research Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648, USA. sgao@fresno.ars.usda.gov
authors.forename: Suduan
authors.initials: S
authors.lastname: Gao
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Trout
mesh_terms: D000498:Allyl Compounds / Q000032:analysis*; D005651:Fumigation; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000498:Allyl Compounds; D006843:Hydrocarbons, Chlorinated; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C023891:1,3-dichloro-1-propene; C100187:chloropicrin