SUNDIAL: Whole farm modelling

Much of the research to improve knowledge about factors controlling nitrate leaching has concentrated on developing principles on a single crop or in a single year. In practice farmers operate within more complex systems, involving rotations of crops and planning timescales of several years. Nitrogen (N) fertiliser applied to the current crop can influence the N available to subsequent crops, and so complete rotations should be planned to optimise the use of N across the whole farm.

The N turnover model SUNDIAL is designed to be used in a ‘carry-forward’ mode, with one year’s run providing the inputs for the next. This allows it to be used to investigate more complex systems involving rotations of crops over several years.

A Decision Support System (DSS) has been constructed around SUNDIAL that allows farmers and policy makers to explore how arable rotations respond to practical strategies for reducing nitrate leaching (Smith & Glendining, 1996). SUNDIAL has been attached to an automated systematic method or scenario generator, which derives all rotations of crops allowed within an imposed set of farming constraints. The N dynamics of each rotation may then be investigated. Constraints are initially defined by restrictions on cropping and management practices, for example due to pest and disease considerations or EC regulations. The N dynamics of all the resulting permutations of crops are automatically simulated and the optimum management strategies selected. Smith and Glendining (1996), Smith et al (1997; 1998) and Glendining and Smith (1999) give further details of the DSS (see References and further reading).

Back to Sundial home page