HR: 0800h
AN: B51B-0361    [Abstracts]
TI: Integrated Impacts of environmental factors on the degradation of fumigants
AU: * Lee, J
EM: jlee@ussl.ars.usda.gov
AF: University of California,Riverside, 900 University Avenue, Riverside, CA 92521, United States
AU: Yates, S R
AF: USDA-ARS, Contaminant Fate and Transport Unit, Salinity Laboratory, 450 West Big Springs road #247, Riverside, CA 92507, United States
AB: Volatilization of fumigants has been concerned as one of air pollution sources. Fumigants are used to control nematodes and soil-born pathogens for a pre-plant treatment to increase the production of high-cash crops. One of technologies to reduce the volatilization of fumigants to atmosphere is to enhance the degradation of fumigants in soil. Fumigant degradation is affected by environmental factors such as moisture content, temperature, initial concentration of injected fumigants, and soil properties. However, effects of each factor on the degradation were limitedly characterized and integrated Impacts from environmental factors has not been described yet. Degradation of 1,3- dichloropropene (1,3-D) was investigated in various condition of temperatures (20-60 „aC), moisture contents (0 \ˇV 30 %) and initial concentrations (0.6 \ˇV 60 mg/kg) with Arlington sandy loam soil. Abiotic and biotic degradation processes were distinguished using two sterilization methods with HgCl2 and autoclave and impacts of environmental factors were separately assessed for abiotic and biotic degradations. Initially, degradation rates (k) of cis and trans 1,3-D isomers were estimated by first-order kinetics and modified depending on impacts from environmental factors. Arrhenius equation and Walkerˇ¦s equation which were conventionally used to describe temperature and moisture effects on degradation were assessed for integrated impacts from environmental factors and logarithmical correlation was observed between initial concentrations of applied fumigants and degradation rates. Understanding integrated impacts of environmental factors on degradation will help to design more effective emission reduction schemes in various conditions and provide more practical parameters for modeling simulations.
DE: 0402 Agricultural systems
SC: Biogeosciences [B]
MN: 2007 Fall Meeting