SUITABILITY ANALYSIS FOR PADDY CULTIVATION SITES USING A MULTI CRITERIA EVALUATION AND GIS APPROACH CASE STUDY: - IMBULPE DS DIVISION IN SRI LANKA

摘要

Rice is not only the staple food for nearly half of the world's population as the major daily source of calories and protein. Land suitability analysis is a prerequisite to achieving optimum utilization of the available land resources. Lack of knowledge on best combination of factors required for production of the rice has contributed to the low production. Therefore the main objective of this study was to evaluate the land suitability for cultivation of rice, in the Imbulpe Divisional Secretariat area in Ratnapura District of Sri Lanka. To achieve this objective, multi-criteria decision making (MCDM) combined with the GIS was used to assess suitable areas for growing this crop. Several topographical (slope and aspect of the land), climatically factors (rainfall), soil properties (texture, pH, drainage and depth), and land use data were selected based on the literature review and experts' opinions for this analysis. A GIS-based Multi Criteria Decision Making technique was carried out for suitability analysis. An Analytical Hierarchical Process was used to rank the various suitability factors and the resulting weights were used to create the suitability map. The result indicates that only 82.53sq.km (32.33%) area can be demarcated as 'highly' and 135.68sq.km (53.15%) as 'moderately' and 37.03sq.km (14.51%) as 'less' suitability categories in the study area. Further this stress that about 85% of the land extent is suitable for paddy cultivation within the study area. Finally, present land cover map was overlaid with the suitability map to identify variances between the present and potential land use. This analysis showed that present paddy cultivated area is about 17.0637sq.km i.e. 6.68% of total area and most of these areas lie in highly and moderately suitable areas. Further results shows that the spatial analytical hierarchy process integrated with GIS is a powerful support system to help decision makers to defining effective management plan for the best production of rice.