Soil Quality Assessment of the Lower Niger River Plain Alluvial Soils in Bayelsa State, Nigeria, for Sustained Productivity

Abstract

Floodplain soils worldwide are very useful for agricultural production and food security. But, the floodplains of Bayelsa State are under-utilized due to lack of technical information and knowledge on the nutrient status and other soil characteristics. This study therefore, assessed the soil quality of lower Niger River floodplain soils in Bayelsa State, Nigeria for sustained productivity and food security. Alluvial soils from different river plains in Bayelsa State, Southern Nigeria were characterized and fertility assessed. Pedogenic soil samples from the levee crest, middle slope, lower slope and recent alluvial soils from the channels of present active rivers were collected from identified genetic horizons of soil profiles and analyzed for physical and chemical properties using standard methods and the soils fertility status evaluated using Soil Fertility Index (SFI) and Soil Evaluation Factor (SEF). The soils were dominantly silt loam followed by silty clay loam and loam except Elemebiri 3 (ELM3) and Trofani 3 (TFN3), dominated by loamy sand and sandy loam. pH (5.31-7.00) was moderately acid to neutral and organic matter content, generally low to moderate, ranging from 0.19-3.88%. Total N values was also low while available P was low to moderate. The exchange complex was dominated by Ca²⁺ and ECEC values were low. The SFI values were higher than the SEF values in al the Soil Mapping Units (SMUs), contributed by pH, organic matter and phosphorus. Both SFI and SEF values decreased with increase in depth for all the soil mapping units except Trofani 1 (TFN1) where the bottom layers recorded higher SFI values and Elemebiri 3 (ELM3) for SEF. Though the soils nutrient concentration was generally low to moderate, both SFI and SEF evaluated the soils as fertile contributed mainly by organic matter, available P and pH. Since biomass accumulation contributed greatly to improvement of soil fertility and physical structure, soil organic matter maintenance should be given top priority in these soils for sustained productivity and food security.