Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/19/2007
Publication Date: 2/23/2007
Citation: Wang, D., He, J., Knuteson, J. 2007. DripFume: A Visual Basic Program For Simulating Distribution And Atmospheric Volatilization Of Soil Fumigants Applied Through Drip Irrigation. Computers and Electronics in Agriculture, Vol 56 (2007) 111-119. Interpretive Summary: Soil fumigants are a special group of volatile pesticides that tend to function and be dispersed in the subsurface soil primarily through vapor phase diffusion. A major environmental concern of soil fumigation is volatilization losses to the atmosphere. Applying soil fumigant chemicals by (surface or subsurface) drip irrigation has an advantage over the conventional shank injection since the drip tapes may be installed and buried prior to chemical application. A graphical user interface program was developed in Visual Basic to simulate distribution and volatilization of soil fumigants when applied through subsurface drip irrigation. The program provides an intuitive user interface by linking databases with default soil and chemical properties to predict subsurface distribution patterns and potential surface volatilization losses of soil fumigants under selected field configurations and application regimes. The output includes a normalized run-time volatilization flux display and concentration profiles that depict distribution patterns. The user can also access other windows to edit or expand available databases or further process the data for management decisions.
Technical Abstract: A Windows-based graphical user interface program (DripFume) was developed in MS Visual Basic (VB) to utilize a two-dimensional multi-phase finite element pesticide transport model to simulate distribution and emission of volatile fumigant chemicals when applied through drip irrigation or shank injection. The program provides an intuitive user interface by linking databases with default soil and chemical properties to predict subsurface distribution patterns and surface volatilization losses of soil fumigants under selected field configurations and application regimes. The interface program was configured to simulate up to three chemicals simultaneously to accommodate the need of fumigation with multiple chemicals. Physical and chemical properties of cis- and trans- isomers of 1,3-dichloropropene and chloropicrin for a typical medium-textured soil were given as default values in the model input. Properties of other soil fumigants can be easily substituted as input options during program initialization. A database containing transport properties of 12 soil groups (from clay to sand) were created in DripFume as selectable sets of input values. Substitution is also allowed if properties of an individual soil are known. The VB output includes a normalized run-time volatilization flux display and selections in post-processing using MS Excel linked by VB. Output options from the post-processing VB/Excel program include data and graphs of cumulative volatilization loss, volatilization flux density, concentration profile by time for a selected location or by location for selected lapsed times after fumigant application. Although there are still limitations in selectable field configurations, the program should be useful in helping pesticide specialists, farm managers, or policy makers to optimize the depth, rate, and duration of fumigant application to achieve the highest possible distribution uniformity and the lowest volatilization loss.