The alluvial soils of Bayelsa State have high agricultural potentials but current information and knowledge on their characteristics, capabilities and suitability are inadequate and obsolete. Hence, efficient management of the soils for increased and sustainable crop production is constrained. Therefore, this study was conducted to characterize, classify and evaluate the suitability of agricultural soils of selected communities along different river systems in Bayelsa State, igeria. Detailed soil survey was conducted in six locations: Elemebiri (ELM), Odoni (ODN), Trofani (TF), Odi (ODI), Koroama (KRM) and Niger Delta University (NDU), representing a total of 18 soil mapping units (SMUs). Three profile pits were dug per location, soils were morphologically described, samples collected at different horizons for physicochemical, mineralogical analyses. and classified according to USDA Soil Taxonomy and FAO World Reference Base. Land and fertility capability classification (LCC and FCC) were assessed and suitability of soils for maize, upland rice, cassava, oil palm, plantain, rubber and coconut cultivation evaluated. Fertility and site quality were evaluated using Soil Fertility Index (SFI) and Soil Evaluation Factor (SEF) techniques. Principal Component Analysis (PCA) was used to detect important soil parameters that influence fertility while soil physical and chemical characteristics were correlated using Pearson correlation.

Soils were of alluvial origin, stratified, with redoximorphic features occurring at different depths; sometimes reaching A-horizon with subsurface grayization. Soils with annual alluvial enrichment were structurally very weak. Textural classification was predominantly silt loam except sandy loam and loamy sand observed in ELM3 and TFN3. Soils were strongly acid to neutral [pH (H20). 4.94-7.00], very low to medium organic C (0.01-5.25%) and total (0.01-0.45%) contents, low to moderate available P (0.6-22 mg/kg), and low in ECEC (1.49-8.06 cmol/kg) with exchange sites dominated by Ca 2+. Quartz dominated the identified mineral phases followed by kaolinite while ferromagnesian minerals contents were low. Soils in ELM I, TFN I, KRM2, ODl2 and NDU2 were classified as Aquic Dystrudepts; ELM2, TFN2, KRM3 and ODN2,(Typic Epiaquepts); OD I and ODI I,(Humic Dystrudepts); KRM I and NDU I (Udic Dystropepts); ELM3 (Eutic Udifluvents); OD 3 (Fluvaquentic Epiaquepts); TF 3 (Aquic Udifluvents), ODl3 (Aerie Epiaquepts) and NDU3 (Fluvaquentic Endoaquepts). respectively. The ELM3 and TFN3 soils were Haplic-Fluvic Fluvisol and Haplic Fluvisol, respectively while all remaining MUs were Fluvic Cambisol. The LCC grouped all the soils into class II except