Integration of a cropping systems simulation model and a relational database for simple farm-scale analyses

Agricultural simulation models are important tools in research , extension, policy formulation, and teaching. Their integration with relational databases allows carrying out complex and comprehensive data analyses of model inputs and outputs. In this article, we describe the integration of a dynamic cropping systems simulation model (CropSystVB) and a relational database (Microsoft Access), with the aim of developing a tool for simple applications at the farm scale. The data model, designed with the entity-relationship framework, represents the structure of the data and allows for organized and retrievable storage of inputs and outputs of the simulation model. In addition to standard CropSystVB's inputs (soil, crop, weather, management events), the integrated tool also requires input data to describe the nutrients produced by livestock and allows for spatially variable fields, soils, and management options. Farm simulation scenarios can be defined, including the actual and alternative configurations of animal breeds, rotations, and crop management. One or more rotations can be simulated for each scenario; each rotation is located on a homogeneous area (a field, or part of it, or a group of fields); each area is described with relevant soil and weather inputs. The Microsoft Access implementation of the integrated tool (www.bsyse. wsu.edn/cropsyst; verified 15 June 2007) includes a Visual Basic for Applications version of the model and tables and forms to store and manage data. An example simulation in an animal farm with six scenarios, obtained by the combination of three animal loads and two irrigation systems (surface and sprinkler), is presented to illustrate its use.