Determination of Erodibility Index of Soils in Some Selected Locations of Girei Local Government Area, Adamawa State, Nigeria

Abstract

The effects of Soil erosion in Girei Local Government Area (LGA), Adamawa State Nigeria developed over the years and led to problems like loss of soil fertility, increased pollution and sedimentation in streams, rivers and clogging of water ways which worsen flooding and thus reduce its ability to support biodiversity. The erodibility indices of soil samples from five randomly selected locations were determined using Wischmeier and Smith formula for some soil characteristics namely, organic matter content (OMC), permeability class index (PCI), structural class index SCI), percent silt + very fine sand and percent sand (100 - % clay). These parameters were investigated and used to determine the soil erodibility factor (SEI), with Wuro Hausa having the highest K value of 0.087, the most erodible and prone to erosion while Sabon Pegi has the lowest K value of 0.0041, the least erodible. The mean K value was calculated as 0.045, which is the erodibility index of Girei soils. Furthermore, laboratory analyses of the soils showed that they have greater proportions of sand and silt thus, found to be erodible, after comparing with standard erodibility indices chart. The average annual soil loss in t/ha/yr was also estimated for each location to confirm the area that is more prone to erosion; Wuro Hausa has the highest soil loss of 61.29 t/ha/yr, while Sabon Pegi has the lowest soil loss of 2.89 t/ha/yr whereas at Tashan Mai Tulare, Anguwan Tampol and Chakamin Dari have soil loss of 10.57, 30.29 and 53.54 t/ha/yr respectively. Provision of various diversion terraces, grade control structures, retarding structures, grass or paved pathways, adequate soil conservation structures, drainage facilities such as buried pipe outlets, shelter belts was recommended to protect the top 60cm depth within these areas.