Integration of land qualities for assessing land suitability for rice in the Chi basin

摘要

Land suitability is generally established based on a combination of land qualities required by rice. In this study, theevaluation is accomplished with objective of examining a quantitative aggregation of land qualities with the multicriteria decisionanalysis (MCDA) model using GIS. The study area is the Chi basin, Northeast Thailand with an area of about 4,947,700 ha. Theprocedure of fusing the land qualities entailed the excluded area, the MCDA model applied for fusing the land qualities in the restwhile the multiplicative model used with limiting conditions. The land qualities used in the MCDA encompass water availability,nutrient availability index, nutrient retention, water retention, salt hazard. Each was treated as a thematic layer in the GISdatabase. The rooting condition is limiting condition used for spatial overlay with the MCDA layer by the multiplicative model.The results obtained are checked against the harvesting plots and Land Development Department (LDD) map, yielding highaccuracy. It is evident from the study that land suitability for rice covers about 26% of the area for highly and moderately suitableland. The GIS technology offers the tool to effectively model the land suitability with its capability in variable fusion.