GIS-Based Impact Assessment of Landscape Characteristics on Soil Moisture Distribution in Mambilla Plateau, Taraba State, Nigeria

Soil moisture is a crucial parameter linked to environmental issues like drought, erosion, flood and landslide. Its significance necessitates the need to understand the variables that could influence its distribution especially in a rugged watershed. Thus, this study assessed the impact of landscape characteristics such as slope, aspect, elevation and soil texture on the spatial distribution of soil moisture index in Mambilla Plateau, Nigeria. Landsat 8 data was applied to evaluate soil moisture, Digital Elevation Model for the landscape characteristics and digital soil map for soil texture in ArcMap environment. The results indicated that elevation, slope and normalized difference vegetation index (NDVI) ranged from1384 to 2399 m, 0 to 155.7% and -0.23 to 0.70. respectively. The soil moisture index (SMI) values ranged from 0.0 to 0.36 with average and standard deviation of 0.17 and 0.09 respectively. Analysis of developed SMI map indicated that the average SMI was higher in the western than eastern regions. Further analysis of impact of landscape characteristics on SMI on pixel-based correlation showed that higher values of average SMI occurred predominantly in areas having higher elevation, with gentler slopes, facing the western direction and having a relatively low proportion of sand. The sandy-clay-loam (26:8:66) texture which has the highest proportion of sand had the lowest average SMI value. This study would be beneficial to watershed managers and farmers in sustainable irrigation planning, geo-hazards and drought monitoring and prediction.