In a companion paper (Sinclair and Walker (1998) Agricultural Systems 56, 341–363) a simple and intuitive method for representing qualitative knowledge held by farmers and researchers about complex agroecosystems, such as agroforestry, was presented. This involved generating sets of statements in natural language. The present paper develops the methodology further through the introduction of a formal method of representation. This involves employing a restricted syntax that facilitates the use of automated reasoning procedures and the development of diagrammatic techniques that help users to appreciate linkages amongst inter-related statements. The role of the resulting formal methodology in the process of knowledge acquisition is then discussed in the context of getting multiple informants, such as members of farming communities, to articulate their understanding of the ecology of their farming system and then developing knowledge bases that are an explicit and representative abstraction of what they knew. It is demonstrated that the iterative evaluation of the knowledge people articulate, enabled by the process of formal representation, significantly increases the coherence, consistency and completeness of the knowledge bases that are generated over what can be achieved with less formal methods of representation. It is, therefore, proposed that the formal methods outlined here provide an effective means of helping researchers and development professionals to develop robust, rigorous and defendable qualitative models of the behaviour of complex agroecosystems.
Walker, D.H.; Sinclair, F.L. Acquiring qualitative knowledge about complex agroecosystems. Part 2: Formal representation. Agricultural Systems (1998) 56 (3) 365-386. [DOI: 10.1016/S0308-521X(97)00049-8]
Acquiring qualitative knowledge about complex agroecosystems. Part 2: Formal representation