Soil Vulnerability and Degradation Assessment of Mountainous Area in Ekoli - Edda, South - East Nigeria

Soil vulnerability and degradation assessment of the mountainous area in Ekoli-Edda, South-East Nigeria was carried out on four experimental sites namely Egu, Ugwuelu 1, Ugwuelu 2, and Ocha. The slope of each study site was divided into three namely summit, mid-slope, and foot slope, and slope attributes were measured. Two profile pits were sunk equidistance apart at each of the slope positions and soil samples were collected from the pits ac- cording to visualized horizonation from the bottom layer to the top. Soil ge- otechnical properties were determined and the slope length and slope angles of all experimental sites recorded. Other physical properties determined in- cluded Atterberg limit, bulk density, moisture content, textural properties, shear strength, and plasticity index. The raw data generated were analyzed for means and percentages following standard procedures. The results showed that the slope length of Egu, Ugwuelu 1, Ugwuelu 2, and Ocha were 52, 105, 115, and 66 meters respectively while the slope angle for all the sites ranged from 14 – 52 degrees at the summit, mid-slope, and foot slope. The soils of Ocha and Egu were non-plastic while the soils of Ugwuelu 1 and Ugwuelu 2 recorded moderately high values of liquid limit, plastic limit, and plasticity index. For all the experimental sites, the safety factor recorded was lower than 1. This was an indication that the areas studied were prone to landslide occur- rence. It was recommended that building and other agricultural activities should only be embarked upon with the advice of professionals.