Many key controlling environmental processes are location specific, operating at an experimental plot scale, whilst the majority of land and resource use decisions in agriculture are taken at the farm-level largely in response to socio-economic drivers. Assessments at higher (e.g. catchment, landscape and regional) scales often fail to adequately reflect system complexity. Adopting an holistic, combined hard and soft systems approach (Clayton and Radcliffe, 1997), this study is based on the premise that an interdisciplinary understanding of this complexity is essential for the assessment of agro-ecosystem sustainability. This can only be achieved by bringing together the latest process based research embodied in bio-physical dynamic models (Hutchins et al., 2002) with sophisticated farm-level financial and economic models of production systems (Matthews et al., 1999, 2002) into an integrated modelling framework focussed at the farm level (Hill, 2001). This will allow relationships between the multiple dimensions of sustainability to be evaluated and the state of agricultural systems to be assessed. However, to give meaning to quantitative sustainability assessments, they must be set within a framework that recognises the diversity of perspectives on sustainable agriculture arising from different perceptions and definitions of sustainability (O'Riordan, 1988), what constitutes agriculture (Smith and McDonald, 1998) and alternative scale considerations (Smit and Smithers, 1993).
The key objectives of this study are to develop a sustainability assessment framework that can be implemented through the development of an integrated modelling framework (Fig. 1) In line with RELU programme objectives, these will facilitate assessment of sustainable agricultural systems, as well as the evaluation of agricultural, environmental and land-use policy.
Specific objectives include:
The key outputs would form the basis for a project under Theme B in the next phase of the RELU research process: