Browsing by Author "Awodoyin, R. O."

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Re-establishment of vegetation on soil contaminated by heavy metals in response to Mexican sunflower and cassava peels composts.
(Enproct Consultants Ltd, 2012) Adejumo, S. A.; Awodoyin, R. O.; Togun, A. O.
Soil contamìnation by industriai wastes contributes greatly to poor soil fertility, ecological imbalance and phytotoxicity. To restore soil fertility and encourage plant growth, remediation of contaminated land becomes pertinent. The use of organic amendment has been reported to be effective for restoration of heavy metal contamiflàted soil Effects of Mexican Sunflower (Tithonia diversifolia: MSC) and Cassava peels (Manihot esculentum: CPC) composts, each applied at 20 and 40 t/ha as well as inorganic fertilizer (NPK 20:10:10) applied at 100 kgN/ha were investigated for restoration and re-vegetation of a degraded battery wastes contaminated site. The experiment was laid out in a Randomized Complete Block Design (RCBD). Ordination method was used to measure flora diversity and abundance among treatments. The species ìmportance in thè eco System was determine d using Relative Importance Values (RIV) before application of compost (BAC), at 4 weeks after compost application (4WACA) and at 8 weeks after compost application (8WACA). Also, thè dominance and plant species distribution at thè three periods were determined from thè Dominance, Shannon and Equitabilty indices. Application of composts increased thè number of individuai plants on thè contaminated site from 1177 at BAC to 2276 at 8 WACA. Species richness increased from 7 species at BAC to 15 species at 8 WACA. Gomphrena celosoides L. had thè highest RIV value (72.4%) at BAC, 67.0% and 49.6%> at 4 WACA and 8 WACA respectively. The dominance index (DI) decreased from 0.8557 at BAC to 0.6008 at 8 WACA. At 8 WACA thè Shannon index (0.9976) and Equitability index (0.3684) were highest. Application of MSC at 40t/ha (MSC40) reduced Pb level in thè soil by 71.6% followed by CPC40 (67.3%), MSC20 (66.1%) and least in CPC20 (49.5%). NPK fertilizer application had no effect on soil Pb level compared to control. Addìtion of compost significantly increased thè plant nxutrients including phosphorus, nitrogen, calcium and magnesium in thè soil compared to inorganic fertilizer. The use of compost reduced Pb contamination, improved soil fertility, enhanced re-vegetation and flora diversity of battery waste contaminated site more than inorganic fertilizer. The prevalence of G. celosioides may suggest that it has potentials for thè phytoremediation oflead-acid battery polluted soil.
Seasonal variations in distribution, heavy metal uptake and proline production of native plants growing on Pb-contaminated site in Ibadan, South-Western,
(Ecological Society of Nigeria, 2015) Adejumo, S. A.; Adeosun, A. A.; Olaniyan, A. B.; Awodoyin, R. O.
Effects of seasonal variations on metal (Lead, Chromium and Cadmium) uptake, proline concentration, density and distribution of metallophytes inhabiting heavy metal polluted site in Ibadan, South-Western Nigeria were investigated. Vegetation surveys and Relative Importance Values (RIV) of different plant species were carried out both at the rainy and dry seasons. The metal uptake and partitioning in plants at different seasons as well as proline content were also determined. The results showed that the Relative Importance Value (RIV), metal uptake and proline production by plants varied depending on the prevailing environmental conditions. During both sampling seasons, same plant species were enumerated on the contaminated site. However, their RIV varied in the two seasons. Sporobolus. pyramidalis was prevalent in the rainy season while Imperata cylindrica had the highest RIV during the dry season. Heavy metal accumulation in different plant species also differed depending on the sampling period and higher concentrations of metals were accumulated during the rainy season compared to the dry season except in Gomphrena celosioides with Pb being the highest at both seasons. The proline concentrations were also species and season dependent. The concentrations varied in different plant species and G. celosioides accumulated more during both seasons while Eleucine indica and Rhyncospora corymbosa had higher concentrations during the dry season compared to rainy season. Plant species abundance, metal uptake and osmolyte production by metallophytes are therefore dependent on the prevailing environmental conditions.