Fuzzy Modelling Of Environmental Suitability Index For Rural Land Use Systems: An Assessment Using A GIS

The increasing use and capability of geocomputation tools, as well as increasing availability of land resource information, offer opportunities to utilise such tools for the effective management of information for planning purposes. One among those is the development of spatially-based models that may be used for efficiently undertaking land suitability assessment based on available information. This paper presents a spatial modelling procedure for the assessment of land suitability using geographical information systems (GIS). The model consists of two sub-models: land suitability indexing and erosion tolerance indexing. Both were modelled based on fuzzy set methodology in a GIS. A soil landscape map (scale 1:100 000), complemented by New South Wales SALIS (Soil And Land Information System), was used in conjunction with a Digital Elevation Model (DEM) to derive a land suitability index (LSI) for cropping. An erosion tolerance index (ETI) was established from the integration of soil loss tolerance (T-value) and average annual soil loss (A) estimated using the Revised Universal Soil Loss Equation (RUSLE). An environmental suitability index (ESI) was then generated from a convex combination of LSI and ETI. The available land capability map (scale 1:25 000) produced by NSW Soil Conservation Service was employed for cross-checking with the model outputs. It was found that the outputs are consistent with that land capability classification scheme. A sensitivity analysis also reveals reasonably good results. The procedures developed show the significance of this model for the basis of identifying and delineating land management units at a detailed scale.