EVALUATION OF SOIL MOISTURE USING TOPOGRAPHIC (DEM), CLIMATE AND SOIL PARAMETERS IN A PIEDMONT AREA OF VILLAVICENCIO

Abstract

A methodology, based on the use of digital elevation model, DEM, Was used to assess soil moisture in a depositional piedmont area of the municipality of Villavicencio in two periods, one wet and one dry. Additionally, the spatiotemporal variation of both climatic and spatial soil moisture and their availability through water balance were considered. This work examines three digital elevation models: SRTM, ASTER, 30m and another generated by photogrammetric restitution (resolution 10m). DEM with the highest quality was SRTM, and this was the source to get topographic and hydrological parameters; Tasseled Cap transformation generated from Landsat 7ETM+ satellite images and physical variables allowed explaining the soil moisture. By interpolation, using IDW and Kriging methods, maps of climatic variables were obtained in order to compare the results with the available moisture through monthly water balance. Multivariate regression indicated that during the rainy season the topographic characterization variables such as classification of curvature, slope and topographic position index are relevant in combination with the bulk density and sand percentage. Inversely; for dry season, the contribution of landforms and topographic relative moisture index with sand percentage inversely explain the soil moisture.

Keywords

• Modelos digitais de elevação
• variáveis geomorfométricas