ABSTRACT

 The study investigated the relationship between plant diversity and soil quality in the reserved forest of Michael Okpara University of Agriculture, Umudike, Abia State. A distinctive characteristic feature ofthe soils ofstudy area showed that it is high in sand, (70.11 %) at relic forest to (78.00 %) at secondary forest land use low - moderate clay and low silt. The highest average clay content was recorded under Relic forest (22.56%) and the lowest in the secondary forest (13.0%) at significant difference (p<0.05). The total nitrogen content in the soils of the area was generally low and had a significant effect on plant species abundance in both the Relic section and the Secondary forest section. The available P was generally moderate in both the land use types compared with the critical level of 15 - 25 mg/kg. In terms of interrelationship between plant species and soil quality, Clay content, pH, Mg_kg and EA were higher in the Relic forest compared to the forest plantation area at both 0-15 cm and 15-30 cm soil depths, while sand content, silt, Nitrogen, OC, OM, Ca, Mg, Na and ECEC at both 0-15 cm and 15-30 cm soil depths were higher in the secondary forest compared to the Relic forest.Sand (P< 0.0001), silt (P = 0.012), clay (P = 0.001), pH (P = 0.013), N (P <0.0001), OM (P = 0.0001) and K (P = 0.011) had a significant effect on plant species abundance in both the Relic forest and the Secondary forest. Of all the soil properties estimated, none showed to have any significant impact on plant species richness (P > 0.05).Therefore, The protection of reserve forests deserve special attention because of the uniqueness and the ecological functions in environmental sustainability