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CARD: Center for Agricultural and Rural Development

CARD Interactive Software Programs

Four interactive programs have been developed at CARD to support applications of the EPIC, APEX, Century, and SWAT models. Access to each program is provided below.


Regional applications of the Environmental Policy Integrated Climate (EPIC) model, originally developed by the USDA and now maintained by the Texas A&M Blacklands Research and Extension Center (BREC), can require thousands of simulation runs. The interactive EPIC (i_EPIC) software package is a Microsoft Windows based program that was developed at CARD to facilitate the management and execution of these large EPIC simulation sets. Input and output data are managed in a consistent Microsoft Access database structure within i_EPIC; diagnostic and editing tools are also provided via both the database and the Microsoft Windows interface. An overview of the EPIC model and an extensive review of EPIC applications is provided in Historical Development and Applications of the EPIC and APEX Models. An extensive reference list of EPIC studies, spin-off model studies, and other related studies can be accessed in the EPIC reference list (pdf).


The interactive APEX (i_APEX) is similar to i_EPIC except that it is used to support large simulation sets of the Agricultural Policy EXtender (APEX) model, which is a multi-field version of EPIC that was developed at and maintained by BREC. An in-depth description of APEX and reported applications is provided in The Agricultural Policy Environmental EXtender (APEX) Model: An Emerging Tool for Landscape and Watershed Environmental Analyses (pdf) which was published in Trans. ASABE in 2010. Several dozen APEX peer-reviewed articles and other studies are included in the EPIC Reference List (pdf).


The interactive CENTURY (i_CENTURY) program was developed at CARD to perform essentially the same functions as those described for i_EPIC, except for the CENTURY carbon and nutrient cycling model that was developed at the Natural Resource Ecology Laboratory at Colorado State University.


The interactive SWAT (i_SWAT) program was developed at CARD to support applications of the USDA Soil and Water Assessment Tool (SWAT) watershed model. Management of input and output data in Microsoft Access, simulation executions, and input data diagnostics can be performed in i_SWAT for SWAT watershed applications ranging from plot scale to large river basins (for example, the Upper Mississippi River Basin). An in-depth description of SWAT and reported applications is provided in The Soil and Water Assessment Tool: Historical Development, Applications, and Future Research Directions (pdf) which was published in Trans. ASABE in 2007. A SWAT literature database containing citations, abstracts and other information pertaining to peer-reviewed journal articles that report SWAT applications or SWAT-relevant research is also accessible at