Land Evaluation for Agricultural Productivity in North-East Thailand Using Landsat TM Data and Geographic Information

The main purpose of this analysis is to develop the methodology for grasping agricultural production comprehensively, timely and exactly, applying satellite data overlaid geographic information. Classification of agro-environmental conditions was attempted using Landsat TM data in North-East Thailand where the production is low and the problem of soil salinization is most serious. Landsat TM data obtained in early dry season (Dec. 18, 1987) and in early wet season (June 11, 1988) were analysed in this experiment. A land use map and a biomass distribution map were created from Landsat image analysis for each season. Then average and difference of biomass between the two seasons were calculated. In addition, soil organic matter distribution map was produced from TM image acquired in early and mid dry season (Feb. 9, 1990). On the other hand, elevation and land inclination angle in topograph map were classified into some levels and evaluated from view point of suitability of crop production. Also soil fertility map which was published in 1973 from Land Development Department of Thai was used as an existing information. Thus, the following thematic maps were prepared through Landsat data analysis and existing data transformation. Landsat origin: Land use map, Average biomass distribution map, Difference biomass distribution map, Soil organic matter distribution map. Existing data origin: Elevation class map, Land inclination class map, Soil fertility map. In the next step, we examined ground truth data and agricultural census of this area to give reasonable weights on the produced maps from the view point of land suitablity for rice and upland crops cultivation, respectively. Overlaying these weighted thematic maps, and finally produced agricultural productivity maps for each paddy and upland field. The properiety and accuracy of the evaluation maps was examined by the agricultural exparts working in this area and proved that the results were reasonable.