Modelling and mapping agricultural output values using farm specific details and environmental databases

Ongoing concerns regarding the economic losses associated with the CAP and the negative environmental impacts of present land use have led to calls fo r land use change and consequent efforts to identify areas which are, from both a financial and social perspective, most appropriate for such conversi on. This paper develops and applies an output value modelling methodology i n which site-specific biophysical factors are combined with farm level data in order to predict input usage and subsequently farm profit. The spatial analytic capabilities of a geographical information system (GIS) are used t o combine the variety of data employed to permit analysis of a large study area (the entirety of Wales) and yield! models of both the mallet and shado w value of output from the two principal agricultural sectors of the area: dairying and sheep farming. The GIS is then used to produce readily interpr etable maps of these values across the study area. The resulting maps are h ighly compatible both with value maps of alternative land uses given in the recent literature and with approaches to policy formulation currently unde r development by a range of UK agencies. Such maps may be used to assist es timation of the Extent and location of farming response to land use policy change.