Thesis Abstract

A study was carried out in the Rubber growing soils of Utagba-ogbe in Ndokwa-West Local Government Area of Delta State, Nigeria. The aim was to characterize the soil in respect of their morphological, physical and chemical properties. Six mapping units were mapped out, and 4 profile pits dug in each of them in order to characterize the soils. Soil samples were also collected from the soil profile horizons and analyzed for their particle size distribution and chemical properties. The chemical properties evaluated were the soil pH, organic matter, total nitrogen, available phosphorus, exchangeable bases, exchange acidity and cation exchange capacity. The morphological properties were also examined and described. These include soil colour, mottle, texture, structure, consistence and horizon boundary. Results of the study showed that the soils irrespective of pedons were deep, non-mottled with varied textures. The structure ranged angular blocky, to sub–angular blocky. The consistence ranged from friable, slight plastic to very plastic in the subsoil horizons. The boundary descriptions were clear, smooth, diffuse, and wavy boundary. The physical characteristics showed that the soils were sandy loam at the surface to sandy clay loam and clay loam in the sub-soil horizons. The soils were generally acidic 5.5 – 6.5, high in organic matter content, total nitrogen, but low to moderate in phosphorus, basic cations, CEC and base saturation. The results showed that the rubber growing soils were moderate in fertility. In order to sustain rubber production for a long time, regular fertilization and liming should be carried out to maintain rubber production in the soil.

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