Profile Distribution of Sesquioxides in the Inland Valley Soils of Central Cross River State, Nigeria.

Impact of Texture on Sesquioxide Distribution in Southeastern Nigerian Soils

“…Concentrations of Fed, Feox and iron activity (Feox/Fed ratio or active Fe) in the bulk soil ranged from 9300.00-11, 400.00, 390-1580 mg kg -1 and 0.04-0.17 respectively (Table 2) and low compared to ranges reported by other workers (Osodeke et al, 2005;Uzoho, 2014;Olatunji et al, 2015;Maniyunda et al, 2015). However, compared to ranges of Fed (Ojo-Atere and Ajowon, 1985;Essoka and Esu 2000) and Feox (Hassan et al, 2005) those of the soils were high. Amongst landscapes, best bulk soil Fed was at the downslope while Feox and Feox/Fed were at the upslope positions.…”

“…It has been noted that Feox/Fed ratio or iron activity is useful in evaluating the age, drainage conditions, degree of weathering and amounts of crystalline or free amorphous oxides in soils (Blume and Schwertmann, 1969;Alamdari et al, 2010). Also, research has shown that ratios greater than 0.35 signify poor drainage while lower values represent well drained condition (Udo, 1980;Essoka and Esu, 2000;Uzoho, 2014). Equally, ratios less than 0.50 have been associated with high degree of…”

“…Sesquioxides play important roles in soil cation exchange reactions, anion adsorption, surface charge, nutrient transformation, swelling and aggregate formation, pollutant retention and precipitation of phosphorus (P) into insoluble compounds (Fe-P and Al-P) thereby restricting their mobility and availability in soils (Hassan et al, 2005;Jelic et al, 2011;Uzoho, 2014). Also, they are useful in the estimation of the degree of weathering, pedogenesis, conferment of soil tints and the cementation of tropical soils thereby influencing their plasticity and compressibility (Essoka and Esu, 2000) Reactivity of Sesquioxides varies with their level of crystalline fraction of sesquioxide, with the less crystalline or amorphous fractions more reactive than the highly crystallized fractions. It has been reported that P and metal sorption are greater in the amorphous Fe and Al oxides than the crystalline oxides (Owusu-Bennoah and Acquaye, 1989).…”

“…Distribution of sesquioxides varies with landscape positions. For instance, variation with landscape positions have been reported in soils of inland valleys (Essoka and Esu, 2000), contrasting land units (Uzoho, 2014), toposequences (Osodeke et al, 2005;Enya et al, 2011), granitic and basement complex rocks (Hassan et al, 2005;Maniyunda et al, 2015;Olatunji et al, 2015) and soil profile depths (Essoka and Esu, 2000). According to Wei et al (2010), landscape influence could be associated with the topography, drainage condition, parent materials and land use types and affects soil chemical properties and water movement conditions.…”