Assessment of Soil Properties in Degraded vs. Rehabilitated Gully Erosion Sites in Imo State, South East Nigeria

This study assesses soil physical and chemical properties in degraded active gully erosion sites compared to rehabilitated gully sites in Imo State, located in Nigeria's South East geopolitical zone. Gully erosion affects over 200,000 hectares of Imo State and is recognised as the most severe form of land degradation in the South East zone, stripping topsoil, removing productive farmland, and undermining rural community infrastructure. Using a comparative field design, soil samples were collected from three active gullies, three gullies rehabilitated using vegetative stabilisation with Vetiver grass and Cajanus cajan for three or more years, and three control undisturbed plots in Orlu, Mbaitoli, and Aboh Mbaise local government areas. Samples were collected at 0 to 15 cm and 15 to 30 cm Soil Sciencehs and analysed for organic carbon, total nitrogen, available phosphorus, texture, bulk density, and penetration resistance. Findings revealed that rehabilitated gully sites showed significant improvements in organic carbon (from 0.3 to 1.2%), reduced bulk density, and improved nitrogen levels compared to active gully sites, though they remained significantly below undisturbed control values even after three years of restoration. Vetiver grass-assisted restoration was particularly effective at reducing penetration resistance in the surface layer. The study recommends continued investment in vegetative rehabilitation programmes, regular monitoring of soil recovery indicators, and the extension of rehabilitation periods to five or more years to approach undisturbed soil quality benchmarks. Keywords: gully erosion, soil rehabilitation, Imo State, Vetiver grass, land degradation.