Mineralogical properties of soils developed from colluvial deposits of Southern Nigeria
John Kingsley, Ackley Ufot Akpan-Idiok, Ayito Esther Okon and Vit Penizek
Abstract: Colluvial deposits are materials of rocks and soil fractions which are detached and transported by gravitational forces. The knowledge of the minerals they compose is vital for both nutrient assessment and pedological studies. The study aimed to investigate the textural and mineralogical properties of soils developed from basement complex geology in reflection to soil nutrient capacity. The study was conducted on a 50-hectare land. Three soil mapping units were identified and labelled as S-I, S-II and S-III. Two profile pits were located in each mapping units except for S -III. A total of nineteen (19) soil samples were obtained from each pedogenic horizons. Particle size analysis was determined analytically while (5) representative samples collected and pretreated for mineral detection using XRD.
Particle size analysis revealed that the sand fraction = 665.3 g/kg, silt fraction = 94.7 g/kg and clay content = 240 g/kg. Texturally, sandy clay loam dominated the soil. This suggested that soils with high sand content are coarse.The XRD analysis revealed that quartz was high the soils ranging from 16.9–73.1% with a mean of 44.4% while others like, hornblende = 0.2–47.1% (mean 28.0%), muscovite =1.6–30.4% (mean 13.0%), kaolinite = 2.0–26.1% (mean 12.1%), illite =3.3–19.3% (mean 10.8%), Microcline = 0.6-23.3% (mean 9.6%), gibbsite = 1.0–15.0% (mean 6.8%), berlinite = 0.3–11.9% (mean 4.7%), feldspar = 0.3–11.6% (mean 4.0%), biotite= 0.9–4.1% (mean 2.2%), Rubidium feldspar = 1.0–3.0% (mean 2.0%) and montmorillonite = 1.0–3.0%
(mean 0.6%).
Texture classes of the soils were sandy clay loam to sandy loam indicating that the colluvial soils of southern Nigeria are dominated by quartz mineral. This further revealed that the soils since they are resistant to weathering intensity they are referred to as old soils. Moreso, the mineralogical and textural characteristics are important in relation to soil fertility studies, of which soil users can incorporate employ in other to make the best crop management decision in solving real soil situation.
Particle size analysis revealed that the sand fraction = 665.3 g/kg, silt fraction = 94.7 g/kg and clay content = 240 g/kg. Texturally, sandy clay loam dominated the soil. This suggested that soils with high sand content are coarse.The XRD analysis revealed that quartz was high the soils ranging from 16.9–73.1% with a mean of 44.4% while others like, hornblende = 0.2–47.1% (mean 28.0%), muscovite =1.6–30.4% (mean 13.0%), kaolinite = 2.0–26.1% (mean 12.1%), illite =3.3–19.3% (mean 10.8%), Microcline = 0.6-23.3% (mean 9.6%), gibbsite = 1.0–15.0% (mean 6.8%), berlinite = 0.3–11.9% (mean 4.7%), feldspar = 0.3–11.6% (mean 4.0%), biotite= 0.9–4.1% (mean 2.2%), Rubidium feldspar = 1.0–3.0% (mean 2.0%) and montmorillonite = 1.0–3.0%
(mean 0.6%).
Texture classes of the soils were sandy clay loam to sandy loam indicating that the colluvial soils of southern Nigeria are dominated by quartz mineral. This further revealed that the soils since they are resistant to weathering intensity they are referred to as old soils. Moreso, the mineralogical and textural characteristics are important in relation to soil fertility studies, of which soil users can incorporate employ in other to make the best crop management decision in solving real soil situation.
Keywords: colluvial soils; mineralogy; soil texture; X-ray diffractogram (XRD)
Date published: 2020-06-29
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