Journal Articles

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Journal Articles (Soil Science)

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Open Access
Compaction 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
Open Access
Hydromorphism - 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.
Open Access
Mermis 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.
Open Access
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.
Open Access
Phosphatase Enzymes in Soils: Nature and Location of the Enzymes and Phosphorus Immobilization and Mineralization
(Faculty of Agriculture, University of Ife, 1980) Adebayo, Adewale
The 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.
Open Access
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.
Open Access
Response 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.
Open Access
Root 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.
Open Access
Slope-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.
Open Access
Tillage, 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.

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