Effect of Application Methods on 1,3‐Dichloropropene Volatilization from Soil under Controlled Conditions

Emissions of fumigants can be an important source of air pollution at soil fumigation sites, and the high emission rates result partly from the use of application methods that are high in volatilization potential. In this study, we compared volatilization of fumigant 1,3‐dichloropropene (1,3‐D) fr.om a sandy loam in 60‐cm packed columns after applied by different methods. The most volatilization was found with injection into uncovered soil at a shallow depth (e.g., 56% loss for the 20‐cm injection) and application via surface drip irrigation (>90%). Volatilization fluxes and cumulative losses, however, rapidly decreased as the injection depth was increased, and the total loss was only 27% for the 40‐cm injection. The commonly used polyethylene plastic was ineffective in reducing the volatilization because of its high permeability to 1,3‐D. Water application after the 20‐cm injection resulted in substantially reduced volatilization, but the least loss (22%) was obtained when an emulsifiable formulation of 1,3‐D, Telone SL, was drip‐applied to the subsurface at 20 cm. Our results indicate that variables most influencing 1,3‐D volatilization are injection depth and water management. By optimizing these variables, application methods with low emission potential can be developed.