Browsing by Author "Fasina AS"

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    Characterization of biochar and phosphorus adsorption in charnockite-originated soils
    (2022) Ilori AO; Ogbonnaya OU; Asaolu JI; Shittu OS; Fasina AS
    Phosphorus, P deficiency by adsorption and fixation of applied P is a critical problem in the tropical soils coupled with wastage of agricultural land and potential nutrients from crop residues’ decomposition necessitates conservancy and sustainable management. Maize stover biochar (mB) and sawmill waste biochar (sB) pyrolysed for 60-minute at 460 °C using Top-Lit Up Draft (TLUD) carbonizer were characterized by morphological, elemental and proximate properties analysed by Scanning Electron Microscope (SEM), CHNS Elemental Analyser and appropriate methods, respectively. Phosphorus (P) adsorption potential of the biochars in charnockite-originated soils were evaluated using adsorption isotherms after adding biochars at 0, 5, 10 and 20% (w/w) with concentrations of 0, 15, 30, 60, 90, 120, 150 mg P/L. SEM showed macropores (>50 nm) embedded biochars, with higher elemental C and H in sB while mB contained higher N, S, O, available P and pH. P-adsorption decreased inconsistently with increasing biochar rates resulting in P-desorption. Low Langmuir adsorption maximum (Qm) were recorded (−0.0350 to 0.1250 mg kg−1) mostly with negative separation factors (RL) and the adsorption process were favourable for mB amended soils having Freundlich heterogeneity factor (nF) of 4.476–9.634 but not for sB amended soils (nF = 0.638–2.812). Biochar production conserved nutrient loss and potentially reduced soil P fixation.
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    Soil organic carbon concentration and stock of arable land use of two agro-ecological zones of Nigeria
    (2021) Kadiri WO; Fasina AS; Babalola TS
    Soil Organic Carbon (SOC) dynamics study in arable land use at different agro-ecological zones is important for recommendation of sustainable land use management practices against detrimental practices. This will provide insight on how to enhance SOC sequestration, improve soil quality and mitigate impact of climate change in different agro-ecological zones. This study was conducted at two agro-ecological zones of Nigeria; upland rainforest (Ado-Ekiti) and southern guinea savanna (Kabba) to evaluate SOC sequestration under arable land use. From the two agro-ecological zones, 1 ha (ha) of land was marked out, five soil samples were randomly collected at four different depths (0–15, 15–30, 30–45, and 45–60 cm) for SOC sequestration study. Higher SOC concentration and stock were observed at Ado-Ekiti site over Kabba site was due to best soil management practices like soil organic and inorganic fertilizers application and incorporation of crop residues. SOC concentration distribution varied greatly (%CV > 35%) and decreased with depth at the two agro-ecological zones. SOC stocks ranged from 6.59 t ha−1 to 24.97 t ha−1 and decreased with depth in similar trend with SOC concentration. Generally, at both sites, soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) decrease with increasing depth especially to 45 cm depth while soil pH increase with increasing depth. Both SOC concentration and stock were observed to have significant positive correlation (P < 0.01; P < 0.05) with SOM (r = 1.000** and 0.996**; and r = 0.991** and 0.707**) and TN (r = 0.936** and 0.934**; and r = 0.992** and 0.691**) at Ado-Ekiti and Kabba sites respectively. This indicated that increase in SOM and TN were associated with increase in SOC stock and concentration. Maximum value (20.33%) of exchangeable sodium percentage (ESP) of above critical value of 15% was recorded at Ado-Ekiti site which requires that soil be managed against sodicity. There was significant difference (t = 2.975**) between the overall mean SOC stocks (14.83 and 9.15 t ha−1 at Ado-Ekiti and Kabba sites respectively) at two agro-ecological zones. Thus, adoption of better soil management practices will enhance SOC sequestration and soil quality at the two agro-ecological zones.