Author : Charlie Navanugraha

Summary : A soil conservation-oriented land use planning technique using Geographic Information System (GIS) technology was developed and used in the mountainous Doi Tung, Chiang Rai Province in Northern Thailand. Land evaluation was conducted using spatial and non-spatial data on soil, land use and climate from secondary sources, actual field survey and laboratory analyses. These data were inputted and stored in the computer, collated and manipulated to generate the desired information with the aid of a GIS called Integrated Land and Watershed Management Information System (ILWIS). Important information outputs included potential and actual erosion maps, soil suitability maps for 11 crops (coffee, ginger, grass, litchi, maize, macadamia nut, pineapple, potato, upland and wetland rice, and tea), recommended erosion control practices map for 5 major crops (maize, coffee, litchi, pineapple, and upland rice), and a land use planning map. Soil suitability for the 11 crops was evaluated using the Department of Land Development of Thailand scheme which is basically like the Land Evaluation for Rainfed Agriculture of the FAO (1983). In soil suitability rating, the land use requirements in term of oxygen availability, rooting condition, nutrient availability and retention, and mechanization potential were considered, using arithmetic method to come up with a suitability rating.