Comparative Evaluation of Soil Fertility and Quality of Soils Developed from Different Parent Materials in Akwa Ibom State, Nigeria

Abstract

This study presents a comparative evaluation of soil fertility and quality of soils formed from different parent materials in Akwa Ibom State, Nigeria. Parent material plays a critical role in the early stages of soil formation, influencing mineral composition, nutrient availability, and overall soil productivity. Three distinct parent materials coastal plain sand, shale stone, and alluvial deposits were selected for the investigation. Within each parent material, three representative profile pits were established and described following the FAO (1990) guidelines for soil profile characterization. Samples were collected from the identified genetic horizons for laboratory analysis, making a total of nine profiles. Results revealed considerable variation in soil physical and chemical properties among the different parent materials. Soils derived from alluvial deposits exhibited sand overlying sandy clay loam textures, while those developed from coastal plain sand and shale stone had sand overlying loamy sand or sandy loam horizons. The mean soil pH was extremely acidic in soils formed from coastal plain sand and shale stone, but moderately acidic in those developed from alluvial deposits. Organic matter content was relatively higher in alluvial soils compared with other parent materials, though not statistically significant (p < 0.05). Similarly, mean available phosphorus (P) was moderate in both coastal plain sand and alluvial soils but low in shale-derived soils. Exchangeable Ca, Mg, K, and ECEC values were also higher in soils formed from alluvial deposits, though variations were statistically insignificant (p < 0.05). Taxonomically, soils derived from coastal plain sand were classified as Typic Hapludults or Haplic Acrisols, and in some cases, Typic Dystrudepts or Dystric Cambisols. Soils from shale stone were identified as Arenic Paleudults or Haplic Acrisols, while those from alluvial deposits were classified as Aeric Endoaquults or Gleyic Acrisols. Overall, soils developed from coastal plain sand and shale stone exhibited intermediate soil quality, whereas those derived from alluvial deposits demonstrated higher quality and fertility potential.