Department of Soil Science

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Department of Soil Science

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Browsing Department of Soil Science by Author "Aduayi, E. A."

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    Making the Soil Nutritious to Plants
    (Obafemi Awolowo University Press, 1985-12-10) Aduayi, E. A.
    Plants are able to live without MAN, but MAN cannot live without plants. If, therefore, MAN has to survive on earth, he has to ensure that the medium in which plants grow, namely the soil, is kept nutritionally balanced. It is on this premise that my lecture will be based. And taking cognizance of the expected heterogeneity of my audience, I will try not to be too technical. With this in view, I shall attempt to develop the topic by posing the questions: What is a soil? And how does the soil acquire its fertility status for the nourishment of plants?
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    Micronutrient Concentration of Okra (Hibiscus esculentus) Leaves and Fruits as Influenced by Nitrogen Fertilization
    (Faculty of Agriculture, University of Ife, 1981) Aduayi, E. A.
    The influence of nitrogen fertilization on leaf and fruit micronutrient composition of okra plants, was studied in field trials from 1975 to 1977. Leaf-Fe was higher at the vegetative stage than at the flowering and fruiting stages of growth. Its concentration decreased steadily at the vegetative stage as nitrogen rates increased, but the converse occurred at the flowering and fruiting stages. Similar effects were noticed in leaf-Mn. The highest Mn, Cu and Zn accumulations in the leaves were observed at fruiting. Leaf-Cu was low at all stages of growth relative to other micronutrients. Fruit-Fe and Mn were generally low compared to the leaf concentration, while fruit-Cu and Zn were almost as high as the leaf concentration.
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    Nitrogen Nutrition of White Yam (Dioscorea rotundata Poir) Grown in Two Selected Locations of Southwestern Nigeria.
    (Obafemi Awolowo University, 1987) Okpon, Stephen Nelson; Aduayi, E. A.
    Soil physical and chemical evaluation was carried out in five selected locations of southern Nigeria viz: Ile-Ife in Oyo State, Ado Ekiti in undo State, Asaba in Bendel State, Abakaliki in Anambra State and Ogoja in Cross River State that are known to support the production of white yam (Dioscorea rotundata Poir). Of these five locations, Ile-Ife and Ogoja were selected for field experiments. Four rates of nitrogen (0, 40, 80 and 120 kg N/ha) as ammonium sulphate [(NH4)2SO4)] were applied to yams grown on ridges for three seasons. Soil physical and chemical investigations revealed that the inherent fertility of the soils which the farmers rely on for yams yield cannot provide sustained productivity. Ammonium sulphate fertilizer at 120 kg N/ha proved adequate for sustaining increased tuber yield of yams at Ile-Ife and Ogoja locations. The fact that the yams were collected in Ile-Ife and planted in Ile-Ife (forest zone) and Ogoja (Savanna zone) did not have any adverse effect on tuber yield and tuber quality in terms of crude protein, starch and glucose contents. These nutrient classes increased proportionately as the N- level increased. High accumulation of mineral nutrients in both the yam flour and the peels were observed for yams grown at Ile-Ife and Ogoja locations. Chemical analysis of the yam flour indicates that with judicious use of N- fertilizer, the nutritional value of the yam flour and peels could be substantially increased in the white yam. It was observed that increasing level of (NH412SO4 resulted in reduction in soil p11 from 6.7 to 5.3 and P from 11.6 to 4.5 ppm in Ogoja whereas it was less felt in Ife. Soil pH was reduced from 6.4 to 6.1 and P from 12.6 to 6.5 ppm in Ife. Statistical analysis showed N- from ammonium sulphate fertilizer highly correlated with yield, protein, starch and glucose.
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    A Preliminary Survey of the Fertility Status of Soils in Ondo State under Traditional Cultivation
    (Faculty of Agriculture, University of Ife, 1979) Adepetu, J. A.; Adebayo, A. A.; Aduayi, E. A.; Alofe, C. O.
    Surface and subsoil samples, as well as maize leaf samples were collected from local fields at about ten kilometers intervals along the major and minor highways across Ondo state in 1977. The samples were subsequently processed and analysed for various components in the laboratory. The surface 0-15cm soil samples showed a mean of 23; 7pp NO3 -N, 13.6ppm avail. P, 119.4ppm exch. K, 1168 ppm exch. Ca, 98.2 ppm exch. Mg, and Na-EDTA-extractable trace elements in the amount 131.9, 9.0, 319 and 1.3ppm of Fe. Zn, Mn, and Cu respectively. About 93% of the samples had a pH value between 5 and 7, while the soils had a mean 0.M content of 1.9% and C.E.C. of 11.4 meq/100g soil. About 77% of samples had a base saturation exceeding 50%. The values of these parameters generally decline down the soil profile to the 90cm depth studied. From the frequency distribution of various amounts of nutrients in the soil and plant tissue samples, it was concluded that N, P and Cu were generally deficient in the soils, while Ca. Mg, Fe. Mn, and Zn appeared adequate for optimum crop growth. However, it was difficult to make a definite statement, one way or the other, about K because of the seemingly contradictory conclusions that could be drawn from evaluating the soil and plant tissue data, which evaluations were based on what are generally believed to be the critical levels of K in soil 3nd maize plant for optimum crop yield. A further study to determine the internal and external critical nutrient requirements of crops in these soils is considered a priority.