Application of Geography Information Systems (GIS) in Building Soil Degradation Map in Da River Basin Segments through Lai Chau, Dien Bien and Son La Provinces

Abstract

Da River basin segments through Lai Chau, Dien Bien, and Son La Provinces is the area with high ​​slope, rugged and divided terrain. Hilly land occupies 90% of the natural area, in which more than 60% is the slope of above 15^o. Applying GIS technology with terrain, soil, climate and land use data to build soil degradation map of the study area shows that most of the study area is degraded, with 55% of the area in slightly degradation level equivalent to 1,801,647 hectares of natural area; medium degradation level is 792,247 hectares, accounting for 24.2%; severe degradation level covers an area of 499,952.5 ha, accounting for 15.27% of the natural area. The causes of soil degradation are ranked in descending order of the level of impact as follows: soil erosion, fertility decline, and laterite process.