Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/29/1999
Publication Date: 3/10/2000
Citation: Wang, D., Knuteson, J.A., Yates, S.R. 2000. Two-dimensional model simulation of 1,3-dichloropropene volatilization and transport in a field soil. Journal of Environmental Quality. 29(2):639-644. Interpretive Summary: Fate and transport of 1,3-D in soil fumigation was simulated with a two- dimensional multiphase solute transport model. Compared to the field measurement, model simulation well predicted the emission flux density and soil gas concentration when 1,3-D was applied with either shallow or deep drip irrigation. The model under predicted emission when the chemical was applied with shank injection. It appears that computer modeling can be use effectively to study the environmental fate and transport of 1,3-D under conditions where diffusion and convective transport in the liquid phases are dominant. In fractured soils where prefential gas flow may occur, significant work is needed in a modeling approach.
Technical Abstract: A modeling study was conducted to simulate 1,3-dichloropropene (1,3-D) emission and concentration distribution in soil profiles when the chemical applied with subsurface drip irrigation with reduced rate. The purpose was evaluate the effect on emission reduction as compared to conventional shank injection application. Simulated scenarios included a shallow drip application at 2.5 cm then covered with a polyethylene film, a deep drip application at 20.3 cm with bare soil surface, and a conventional shank injection at 30.5 cm with a regular application rate. A convective and diffusive two-dimensional model was used to simulate the simultaneous transport of 1,3-D in both liquid and gaseous phases. Diurnal variations o soil temperature were predicted during each time increment and were used to correct changes to 1,3-D diffusion coefficient and the Henry's constant. Predicted 1,3-D emissions compared well with field measurements for the shallow and deep drip irrigation treatments. The model simulation underpredicted 1,3-D emission in the shank injection plot where other transport mechanisms such as gas phase convection likely occurred during an immediately after application. Results from the modeling study indicate th computer simulation can be used effectively to study the environmental fate and transport of 1,3-D under conditions where diffusion and convective transport in the liquid phases are dominant. Applying 1,3-D with subsurfac drip irrigation appeared to be useful for emission reduction.