Browsing by Author "Oti, Nnenna Nnannaya"

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    Cassava response to natural and simulated erosion on the ultisols of Owerri, Southeastern Nigeria
    (U. P., 2016) Oti, Nnenna Nnannaya
    The impact of erosion on soil productivity is soil, crop and environment specific. It is therefore important that erosion-soil-productivity relationships be established for each soil type and ecological zone. The results reported here are a part of an elaborate series of studies to quantify the relationship between natural and simulated erosion on the yield of major crops on the ultisols of Owerri, southeastern Nigeria. Two crops of cassava were grown between 1998 – 2000 on non-eroded (NE), slightly (S), moderately (M) and severely (Sv) eroded phases of ultisols within the Otamiri watershed of Owerri. Simultaneously, desurphased experiments with three levels of topsoil depth removals (2.5, 5.0, 7.5, cm) were conducted on the non- eroded reference plateau terrain. Natural erosion had no adverse effect on plant establishment and tuber numbers, but led to significant reductions of total dry matter, stem and storage root yields. For instance, the relative yield performance of fresh tubers in the 1998/1999 planting (40 WAP) was in the order 100:52:59:36 for NE:S:M:Sv and the corresponding yield values were 29.6, 15.4, 17.4 and 10.7 t/ha respectively. Desurphasing led to drastic reductions on all yield parameters and tuber yield declines of 91% were recorded when 7.5 cm of topsoil was removed. Linear functions of storage root yield decline per cm of topsoil eroded naturally was 1.74 t/ha, and 10.34 t/ha for mechanical topsoil removal. The best-fit indicators for predicting tuber yields were soil organic matter (SOM), aluminium saturation, (Ca + Mg)/ (Al + H) ratio, available water capacity (AWC), bulk density (BD) and A-horizon depth, accounting for 68.9 % of the variability in tuber yields. The simulation of erosion through mechanical topsoil removal exaggerated the impact of erosion on cassava yield by factor of 6, therefore the results from such experiments should be used with caution.
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    Cytotoxic investigation of crude oil impact on selected crops via pre-planting and post-planting treatments
    (University of Oradea Publishing House, 2023) Oti, Nnenna Nnannaya; Ogbulie, Toochukwu Ekwutosi; Nwachukwu, Augusta Anuli; Madubuike, Mercy Ngozi
    Oil spills destroy farmlands with detrimental impact on agricultural crops, thereby deteriorating the health of humans and other animals that consume the crops from the polluted regions. Assays for this study were conducted between two soil groups polluted with 100 mL crude oil (A-soil polluted before planting [PB] and B-soil polluted two weeks after planting [PA]) within a period of 28 days from their pollution time; at Federal University of Technology, Owerri, Nigeria. The impact of oil spill on three edible plants (Allium cepa, Telfairia occidentalis and Zea mays) were evaluated through plant growth measurement, total chlorophyll test done by spectrophotometry of leaf samples and histo-anatomical investigations. Results obtained at the end of the experiment showed a decrease in plant height, leaf area and leaf number for all the polluted plants compared with their controls. However, plants grown on group A soil experienced delayed emergence and retarded growth, but survived better than plants grown on group B soil. The photomicrographs revealed alterations and anomalies in leaf structures for both polluted groups as compared to their control samples. A notable decline in total chlorophyll contents occurred amongst the plants in group B when compared to plants in group A. Therefore, this study deduced an elevated cytotoxic effect of crude oil in all the polluted crop samples, except for mild anomalies observed in the leaves of T. occidentalis in group A (UPB); which also showed no physical sign of crude oil pollution based on the non-observance of leaf yellowing, deformity or defoliation.