Kayode Ogunsusi

Bitumen-derived heavy metals pose a serious threat to the environment by contaminating soil and harming plants, animals, and ecosystems. The study was carried out at Ode-Irele in Ondo State of Nigeria where there were seepages of bitumen as well as exploratory activities. Composite samples of soils in bitumen seepages and exploratory sites were collected to a depth of 15cm and that of the control was obtained at Ebute-Irele. Heavy metals in soils – Mn, Fe, Cu, Zn, Pb, Cr, Cd, Ni, V, and As were determined using atomic absorption spectrometry. Data were analyzed using descriptive statistics and t-tests of unpaired samples. Results showed that Mn (805.00 ± 136.30 mg/kg, 870 ± 198.00 mg/kg), Fe (992.50 ± 115.30 mg/kg, 1110.00 ± 141.40 mg/kg), Pb (8.0 ± 3.00 mg/kg, 290 ± 56.60 mg/kg), and As (4.80 ± 1.30 mg/kg, 5.00 ± 0.00 mg/kg) were respectively common to soils where there were bitumen seepages and where exploratory activities had taken place with higher concentrations than corresponding values in bitumen. The values of Mn, Cu, Zn, Pb, Ni, As, Cr and Cd respectively in both seepage and exploratory soils exceeded FEPA (1991) guidelines. Higher concentrations of heavy metals in bitumen-polluted soil should be continuously monitored during bitumen mining as they may represent significant environmental risks to soil conservation

Enhancing crop yield through the adoption of fertility and eco-system enhancing agricultural technologies is an important step towards a sustainable food production system among rural farming households in developing countries. The study was therefore conducted using cross-sectional data from smallholder farming households to assess the effect of agroforestry technology on the yield of maize in Sapoba forest reserve in Orhionmwon Local Government area of Edo State, Nigeria. We correct for endogeneity in adoption and employ instrumental variables analysis to investigate the effect of adoption of the technology on the yield of maize. Our analysis shows that the adoption of the technology had positive and significant effect on the yield of maize in the study area. This finding provides empirical evidence that the yield of maize among smallholder maize farmers can be raised through the use of agroforestry technology.