Department of Soil Science
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- ItemOpen AccessSoils, Civilisations and the March of Time(Obafemi Awolowo University Press, 1978-01-09) Ashaye, T. I.Most of the efforts of man to understand how the earth was formed and the nature of it have only yielded the following: first, there was a molten mass called "magma". This magma cooled leading to barren landscapes of mountains, deserts and steaming lava fields. The earliest forms of life were very primitive. Land plants appeared on the earth surface 400 million years ago and mammals 250 million years ago. Homo sapiens emerged within the last million years. On arrival man began to domesticate animals and till the ground in order to cultivate food crops. The soil referred to in this lecture can therefore not be different in definition from what Homo sapiens worked upon but the period of his activities and the impact of these activities on human culture and progress can only be extracted from recorded history. This period is more likely to be much shorter than one million years.
- ItemOpen AccessTillage, seed bed configuration and mulching: effects on soil physical properties, and responses of cassava, cowpea and maize(Faculty of Agriculture, University of Ife, 1979) Aina, P. O.The influence of tillage, and 2 seed bed configurations on soil physical properties and responses of cassava (Manihot esculenta), cowpea (Vignia unguiculata L. Walpa), and maize (Zea mays L.) was studied for two cropping seasons in 1978 under mulch and no-mulch conditions. The study was conducted on an Alfisol at the Ife (Nigeria) University teaching and Research Farm. Tillage reduced soil bulk density at planting (1.43 g/cc) by 23%. Six weeks after seeding, the bulk density of ridges and mounds had increased by 24% compared to 3.5% increase for no-tillage plots under bare conditions. Mulching reduced soil compaction of tilled plots by 50% while compaction was negligible on the mulched no-tillage plots. Soil moisture reserve, 3 weeks after planting was higher by 5 and 8 percent (of cumulative rainfall) respectively for no-tillage and ridged plots compared to mounds under unmulched conditions. In the same correspondent order soil temperature was respectively, lower by 3oC and 1oC than in mounds during the period. Mulch effect on soil moisture and temperature was more significant with no-tillage compared to ridges and mounds. Yield of cassava was reduced by only 13% when grown with no-tillage plus mulch, compared to 40% with no-tillage without mulch. There was no significant effect of tillage on cowpea yield. Yield results reflected differences in soil moisture and temperature regimes which influenced seedling germination, stand and subsequent plant development.
- ItemOpen AccessMermis sp. [Nematoda: Mermithidae] as a Parasite of Zonocerus variegatus linnaeus [Orthoptera: Pyrgo morphidae](Faculty of Agriculture, University of Ife, 1979) Matanmi, Babajide A.Mermis sp. (Nematoda: Mermithidae) was consistently encountered in dissected specimens of Zonocerus variegatus (Linnaeus) collected at random from the field in the Ile-Ife area of Nigeria. In this study, parasitization at different locations ranged between 0 to 7.58%. Although this parasite may constitute an important factor in the mortality of Z. variegatus, it does not appear to be efficient as a potential biological control tool.
- ItemOpen AccessRoot growth and nutrient flux of cowpea under field condition(Faculty of Agriculture, University of Ife, 1979) ADEPETU, J. A.Field studies were conducted on an Egbeda soil series (Oxic Paleustalf) to determine the root length, root surface area and the nutrient flux into cowpea root at five days intervals of growth from 5 to 50 days after emergence. In companion study, a solution culture study was conducted in the greenhouse to determine if information from greenhouse investigations are valid indices of field situations regarding the characteristic changes in root growth with age of cowpea. A speculation was made from the result of the field study concerning the best time of P and K fertilizer application for greatest yield. To test the validity of this speculation a study was set up on the field whereby cowpea dry pod weights produced from applying the fertilizer 10, 20. 30, 40 arid 50 days after emergence were determined. Cowpea root length increased exponentially with plant age between 5 and 50 days after emergence, even though the relationship tend to be linear at the very young growth stages. The extent of agreement between root growth on the field and in the greenhouse suggests that solution culture research results could be applied to field conditions. Nutrient flux was greatest when the plant was 5 days old, decreased rapidly with age of the plant to about 28 days old, remained constant for the next few days, then increased agilin and stayed relatively high between 40 and 50 days. Dry pod yield obtained by fertilizing cowpea with P and K of 40 days old was significantly greater (P4 0.5) than yields from 20.30 and 50 days application dates, but not significantly superior (P> 0.5) to yield from applying fertilizer at 10 days. It is concluded that availability of P and K to cowpea root in the soil is critical to optimum pod yield at the early vegetative growth stage (about 10 days after emergence) and during the early flowering stage, but apparently more critical at the early flowering than the young growth stage.
- ItemOpen AccessA 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.
- ItemOpen AccessPhosphatase Enzymes in Soils: Nature and Location of the Enzymes and Phosphorus Immobilization and Mineralization(Faculty of Agriculture, University of Ife, 1980) Adebayo, AdewaleThe nature and location of phosphatase enzymes produced by soil microorganisms under different cropping and ecological conditions were evaluated by incubating the supernatant of a 1:10 soil-distilled water suspension for 40 weeks in microbial P- surplus and P- deficient conditions.. At .various time intervals, the cell-free, cell-bound, total dissolved P, dissolved inorganic P and turbidity of the cultures were determined. Results indicated that most of the phosphatase enzymes existed in a cell-bound rather than cell-free state irrespective of the P status of the medium during the first 8 weeks of incubation. Total phosphatase activity showed little tendency to decline with continued incubation However, in all the systems the rate and extent of organic P mineralization varied but was not related to phosphatise activity. Phosphatase activity was also not related to the living biomass in these cultures.
- ItemOpen AccessMicronutrient 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.
- ItemOpen AccessResponse of Two Lowland Rice Varieties to N, P and a Combination of Other Nutrients in a Flooded Soil(Faculty of Agriculture, University of Ife, 1984) Obi, A. O.; Adepetu, J. A.A 4x3x2x2 factorial experiment was conducted to evaluate the effects of N, P and a combination of some other nutrients on grain yields of two rice varieties under hydromorphic soil conditions, in the &forest of southern Nigeria. The low yielding variety (IR-20) responded better to fertilizer application than the higher yielding variety (OM). The best rates of N and P application to both rice varieties in this flooded soil were 60kg N/ha and 25kg N P/ha. Yield response to a combination of l00kg K, 40kg Mg, 5kg Cu, 2kg Zn and 2kg Fe per ha was significant during both years of cropping. Yield response to NP, and the combined application of the other nutrients were greater during the second than the first year of cropping.
- ItemOpen AccessLand Evaluation under Different Environmental and Geological Conditions in Southern Nigeria.(Obafemi Awolowo University, 1985) Aiboni, Victoria; Ashaye, T. I.Soils of Ibadan and Remo were evaluated for the cultivation of yam and cassava. The soils in farmers' plots in both sites were characterized by their morphological, physical, chemical and mineralogical properties. The slope, climatic and other land surface features limiting the cultivation of yam and cassava were also identified. Actual and potential land productivity indices were developed based on the soil, slope and climatic characteristics limiting the cultivation of yam and cassava at both sites. Ibadan site is underlain by Precambrian basement complex rocks whilst Remo site overlies cretaceous sedimentary rocks. Twelve soil series were identified in Ibadan site and nine in Remo site. Forty-five plots under yam and cassava were selected in Ibadan site and sixty-nine in Remo site to cover the various soil series. The farm, management level was assessed with questionnaire and direct observation of individual farm land. Parameters considered in the land productivity index are soil depth, drainage, soil texture, surface stoniness, slope, annual rainfall, primary nutrients, organic matter, base saturation, mineral reserve and nature of clay mineral. Productivity index was developed with appropriate ranges in percentage to reflect individual factor. Soil fertility and potential productivity indices were also developed. Land productivity index range from 3.77 to 60.91 and 19.82 to 48.27 for Ibadan and Remo, respectively. Cassava yield ranged from 6.30 to 11.50t/ha and 5.23 to 7.26t/ha for Ibadan and Remo, respectively. Yam yield ranged from 3.75 to 6.00t/ha and 6.20 to 8.00t/ha in Ibadan and Remo, respectively. The wide range of indices recorded for Ibadan soils is a reflection of the complexity of the parent material. Correlation coefficients between calculated and measured yield are r = 0.81 and 0.77 for yam and cassava in Ibadan site and r = -0.95 and -0.22 for yam and cassava in Remo site. The poor correlation of yields in Remo site may be due to the greater response of these soils to management. Chi-squared analysis indicates the independence between measured and calculated yield in both sites.
- ItemOpen AccessHydromorphism - Its Definition and Correlation between Three Major Classification Systems with Reference to West Africa(Faculty of Agriculture, University of Ife, 1985) Okusami, T. A.Hydromorphic soils may be defined simply as any wetland soil that will not support crops (or plants), with aerobic edaphic requirements, during the peak of the groundwater recharge. The influence of the water-table is largely controlled by the texture of the profile. This is of significance because the capillary fringe of any water-table may be as saturated as those horizons under the water-table, and this tends to increase the height of the groundwater. A depth of 100 cm. to a saturated zone is suggested as the depth below which a pedon ceases to become aquic or show features associated with hydromorphism that could limit the environment to anaerobic crops. For a general landuse purpose, a probable depth of 150 cm. is suggested as the depth beyond which a pedon ceases to become hydromorphic. Because hydromorphism does not preclude those soil forming processes peculiar to the well-drained upland soils, classification as outlined in Soil Taxonomy (USDA) could be appropriate for the classification of hydromorphic soils. The aquic prefix points to the influence of the water regime on the pedogenesis and properties of the soils concerned. Attempt at correlating the three systems, viz. USDA, FAO - UNESCO and French was made.
- ItemOpen AccessSlope-soil Relationships on an Aberrant Toposequence in Ife Area of South Western Nigeria: Variabilities in Soil Properties(Faculty of Agriculture, University of Ife, 1985) Okusami, T. A.; Oyediran, G. O.Soils located on the upper-slope segment of a toposequence were studied to observe their properties and evaluate thc slope-soil variabilities thereof. In addition, the soils were classified. This toposequence has no middle-slope soils that normally occupy physiographic units between those soils formed in upper slope in-situ materials and Gambari series (Smyth and Montgomery, 1962). The soils studied occupy summit but crestal position (FBI), the lower crestal position (FB2), and the physiographically slightly sloping lower upper-slope segment (FB3, FB4 and FB6) of the landscape. They are located on 2%, 5%, 3%, 2.5% and 3% slopes respectively. All the soils belong to Iwo series with the greatest soil morphological variabilities expressed in the BC, and in C horizons. : Typically, the surface horizons (0-30cm) range from dark yellowish brown (10 YR 314 or 414 to dark brown (7.5 YR 518). A typical B horizon is strong brown (7.5 YR 518) with a depth range of 35-95cm. Soil physical and chemical properties mostly show statistically insignificant differences between soils located on different physiographic/slope positions. However, there are significant differences in chroma between FB3, FB4 profiles and others. Significant differences exist between some of the soil profiles for their silt content. Soils are mostly in the strongly acid to extremely acid range. Exchangeable Mg is the least variable (C.V. of 9.1%) of the exchangeable cations. These soils are classified as Paleustults in the USDA system with an equivalent of Ferric Acrisols and Ferric Lixisols in the FAO-Unesco system.
- ItemOpen AccessCompaction and Moisture Suction Effects on Soil Strength and Crop Emergence(Faculty of Agriculture, University of Ife, 1985) Aina, P. O.; Fapohunda, H. O.; Idowu, J.Laboratory studies were conducted to determine the effects of four levels of soil compaction and five moisture suctions on the relationship between penetrometer soil strength and emergence of maize and cowpea seedlings for five contrasting soils of Western Nigeria. Compaction (bulk density) and moisture suction accounted for 75-- 88% of observed variation in soil strength and affected seedling emergence at specified soil strengths. The effect of compaction or moisture suction on the relation of seedling emergence to soil strength depended on 5oil and crop species. The rate of cowpea seedling emergence, which was about two-thirds that of maize, was more adversely affected by compaction than by high moisture suction. Cowpea emergence ceased when soil strengths exceeded 8 kg/cm2 in the clay loam or 10 kg/cm2 in the sandy clay loam and sandy loams, while corresponding values for maize were 14 kg/cm2 for the clay loam and 18 kg/cm2 for the other soils
- ItemOpen AccessSoil Test and Nitrogen, Phosphorus and Potassium Requirement of Maize in Southwestern Nigeria.(Obafemi Awolowo University, 1985) Adebusuyi, Benson Adekunle; Aduayi, E.A.; Sobulo, R.A.Soil testing as a fertilizer advisory service to farmers is not common in Nigeria. Method of sample treatment and time of sampling in relation to fertilizer treatment need to be properly established. In order to shorten the time required for analysis, a multi-element extractant has to be developed to cover more than one element at a shaking time. This study was undertaken to evaluate suitable and rapid methods for a soil testing programme. Simultaneous extraction of P and K at a shaking time of 5 minutes was carried out. Bray II was recommended for the simultaneous extraction of P and K. The field trial was conducted at five locations viz: Ikenne, Akure, Agbede, Ilorin and Ilora. Available nitrogen, NO3-N was the best index of N availability in soil for short period of four weeks but the poorest under continuous cropping. Soil N critical levels were established with deficient values of 20 ppm NO3-N, 0.05% total N and 0.7% carbon while the critical values were 30 ppm NO3-N, 0.11% total. N and 1.26% carbon. Field correlation and calibration studies was used to establish soil critical P and K. Maize responded to N fertilizer at Ilorin, a savanna zone up to 150 Kg N/ha but lower response to N was observed in forest zone. The critical soil P levels at about 90% relative yield in the field and glasshouse were 9.5 and 12 ppm P while the corresponding deficient levels at 50% relative yield were 6 and 7.5 ppm P respectively. The critical soil K by Bray I, Bray II and NH4 0AC in the field study was higher than greenhouse value with a range of 0.33 - 0.38 me K/100g. The critical N, P and K concentration in maize leaf. The tissue at four and eight weeks stage were compared. The relationship between the tissue content at four weeks and relative yield was better than at eight weeks while the critical values were 3.2%, 0.4% and 3.9% N, P and K at four weeks respectively and 2.80%, 0.29% and 2.50% N, P and K for eight weeks respectively.
- ItemOpen AccessMaking 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?
- ItemOpen AccessNitrogen 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.
- ItemOpen AccessSoil and Nigerian Food Security(Obafemi Awolowo University Press, 1997-10-14) Adepetu, J. A.Soil is the most important factor in agricultural production: its function as the medium for plant growth underscores this importance. At any location suitable for plant growth, the yield of crops, even varieties with the most high yielding potentials, depend on soil quality and soil management practices applied to cultivating the crop. For this reason, we must regard soil as our resource base for a, sustainable future. Among natural resources, soils are exceedingly responsive to human influence. With careful management we can improve their properties and productive potentials. But much more easily, soils can be destroyed and rendered less productive by misuse and thoughtless development.
- ItemOpen AccessEffect of Cowpea Mosaic Virus on Nodulation and Nitrogen Fixation in Cultivars of Cowpea Vigna Unguiculata (L.) Walp(2015-05-19) Samuel, Chinedum JohnsonThis study was carried out to assess the effects of Cowpea Mosaic Virus (CMV) infection on agronomic parameters, nodulation and N2 fixation in four cultivars of cowpea namely IFOB, Ife Brown, Obwell Standard and BPQ/C with and without Starter N application in the greenhouse. This was with the aim of screening for which Cowpea variety is naturally resistant to the Cowpea Mosaic Virus. The first experiment was set up using a Randomized Complete Block Design (RCBD) on treatments consisting of four cultivars of cowpea in two sets: (a) disease free and (b) infected with CMV, each replicated four times. The second experiment involved the assessment of the effect of Starter nitrogen (N) on nodulation and nitrogen fixation in cultivars of cowpea inoculated with CMV. The layout was also set up using RCBD and the treatment consisted of four cultivars of cowpea also in two sets: (a) inoculated with CMV plus Starter N and (b) the second set uninoculated without Starter N each replicated three times. Analysis of variance (ANOVA) was used to analyze the treatment effects. Means of the treatment effects were also compared using Duncans New Multiple Range Test (DNMRT) at 0.05 level of significance. Results of the study showed that plant height, days to 50% flowering, shoot, root and nodule dry weight, number of nodules, total nitrogen content and total nitrogen fixed by inoculated Ife Brown, Obwell Standard and BPQ/C were significantly reduced (P<0.05) with or without Starter N when compared with their corresponding uninoculated cultivars, except for IFOB which showed a high level of resistance to inoculation with CMV, with or without Starter N. This study also showed that there was no improvement in the performance of the infected cowpea cultivars in presence of Starter N. It was concluded that while Obwell Standard, BPQ/C and Ife Brown were susceptible to CMV with or without Starter nitrogen, IFOB was resistant.