title: Effect of drip application of ammonium thiosulfate on fumigant degradation in soil columns.
abstract: Low permeability tarps can effectively minimize fumigant emissions while improving fumigation efficacy by retaining fumigants under the tarp. However, when planting holes are cut through the tarps, high-concentration fumigants may be released and result in environmental and worker safety hazards. In a 11-day column study, we explored the effect of drip irrigation application of ammonium thiosulfate (ATS) on 1,3-dichloropropene (1,3-D) and chloropicrin (CP) degradation in soil. Decrease of 1,3-D and CP concentrations in soil-gas phase followed a three-parameter logistic equation for all treatments. It was slowest in the control with a half-life ( t 1/2) of 86.0 h for 1,3-D and of 16.3 h for CP and most rapid when ATS was applied at 4:1 ATS/fumigant molar ratio with a half-life of 9.5 h for 1,3-D and of 5.5 h for CP. Our results indicate that applying ATS via the drip-irrigation systems to soil can accelerate fumigant degradation in soil and thus reduce emissions. This technical solution may be applicable in raised-bed strawberry production where drip-application of fumigants under tarps has become common.
authors.affiliation: Department of Plant Sciences, University of California, Davis, 1636 East Alisal Street, Salinas, California 93905, USA. rqin@fresno.ars.usda.gov
authors.forename: Ruijun
authors.initials: R
authors.lastname: Qin
authors.forename: Suduan
authors.initials: S
authors.lastname: Gao
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Hanson
authors.forename: Jason A
authors.initials: JA
authors.lastname: McDonald
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Trout
authors.forename: Husein
authors.initials: H
authors.lastname: Ajwa
mesh_terms: D000498:Allyl Compounds / Q000008:administration & dosage / Q000737:chemistry*; D005651:Fumigation; D006207:Half-Life; D006843:Hydrocarbons, Chlorinated / Q000008:administration & dosage / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis; D010575:Pesticides / Q000737:chemistry*; D012987:Soil / Q000032:analysis*; D013885:Thiosulfates / Q000008:administration & dosage*
chemical_list: D000498:Allyl Compounds; D006843:Hydrocarbons, Chlorinated; D010573:Pesticide Residues; D010575:Pesticides; D012987:Soil; D013885:Thiosulfates; C023891:1,3-dichloro-1-propene; C035309:ammonium thiosulfate; C100187:chloropicrin