Two-dimensional model simulation of 1,3-dichloropropene volatilization andtransport in a field soil

A modeling study was conducted to simulate 1,3-dichloropropene (1,3-D) emis sion and concentration distribution in soil profiles when the chemical was applied with subsurface drip irrigation with reduced rate. The purpose was to evaluate the effect on emission reduction as compared with conventional shank injection application, To compare with field measurements, simulated scenarios included a shallow drip application at 2.5 cm, revered with a pol yethylene film; a deep drip application at 20.3 cm with bare soil surface; and a conventional shank injection st 30.5 cm with a regular application ra te. A convective and diffusive two-dimensional model was used to simulate t he simultaneous transport of 1,3-D in both liquid and gaseous phases. Diurn al variations of soil temperature were predicted to calculate 1,3-D diffusi on coefficient and the Henry's constant. Predicted 1,3-D emissions compared well with field measurements for the shallow and deep drip irrigation trea tments. The model simulation underpredicted 1,3-D emission in the shank inj ection plot, where other transport mechanisms such as gas phase convection likely occurred during and immediately after application, Results from the modeling study indicate that computer simulation ran be used effectively to study the environmental fate and transport of 1,3-D under conditions where vapor phase diffusion and liquid phase convection are the dominant transpo rt mechanisms. Applying 1,3-D with subsurface drip irrigation appeared to b e useful for emission reduction.