INTEGRATED MULTI-INDEX EVALUATION OF STRUCTURAL VULNERABILITY AND ENVIRONMENTAL QUALITY IN ERODING COASTAL SOILS OF BAYELSA STATE, NIGERIA

Soil structural stability is a key determinant of erosion resistance, environmental quality, and sustainable land use in coastal ecosystems. This study assessed the structural vulnerability and environmental quality of selected erosion-prone coastal soils in Bayelsa State, Nigeria, using an integrated multi-index evaluation approach. Soil samples (0–20 cm) were obtained from fifteen riverine communities located within Yenagoa, Ogbia, and Southern Ijaw Local Government Areas. Soil structural quality was assessed using dry-stable aggregates (DSA), water-stable aggregates (WSA), mean weight diameter (MWD), geometric mean diameter (GMD), potential structural deformation index (PSDI), water stability index (WSI), aggregate stability ratio (ASR), and aggregate stability index (ASI). The evaluated indices were subsequently integrated into an Environmental Quality Index (EQI) to enable comparison among the study locations. The results revealed considerable spatial variability in soil structural properties across the study locations. DSA and WSA values ranged from 33.08 to 63.30 % and from 31.61 to 43.09%, respectively, suggesting moderate susceptibility to structural degradation and water erosion. The wet mean weight diameter (MWDw) and PSDI values suggested varying degrees of vulnerability to slaking and structural deformation under intense rainfall conditions. EQI ranking identified Tariladei, Ikpetiama, and Agbura as structurally resilient soils, whereas Amassoma, Igeibiri, and Angiama were more susceptible to degradation. The findings demonstrate that the multi-index approach is effective for evaluating soil structural condition and prioritizing conservation interventions in the dynamic coastal environments of the Niger Delta.