Soils Of Southwestern Nigeria Research Articles

Investigating the competency of some selected soft computing techniques for modeling of lateritic soil strength based on index properties

This study aims to assess the capability of some soft computing techniques including ANN, M5P and RF to accurately predict the strength of selected lateritic soils in southwestern Nigeria from index properties including specific gravity, linear shrinkage, liquid limit, plasticity index, fine sand content, and fines content. To achieve this goal, the experimental dataset obtained from the laboratory analysis of three hundred soil samples taken from thirty different lateritic deposits within southwestern Nigeria was divided into model and gaging dataset. The model dataset contains two hundred and forty data points, which were divided into 70% for training and 15% each for testing and validation of the proposed models. The gaging dataset contains sixty data points, which were used to validate the proposed models against prominent existing models in the literature. The models performances were evaluated using various statistical estimators. Based on the statistical estimators, the proposed models outperformed the existing models in the literature and provided satisfactory performances, thus, they are validated. The obtained R2 values using the ANN model are 0.9967, 0.9963, 0.9989, and 0.9852 for training, testing, validation, and gaging dataset, respectively; the R2 values obtained for M5P model are 0.6676, 0.5501, 0.636 and 0.6727; and the R2 values for RF model are 0.8346, 0.6380, 0.7564, and 0.7901. This implies that ANN provided the most reliable model for the prediction of the soil strength. Thus, ANN is strongly recommended for prediction of lateritic soil strength.

Evaluation of phytochemicals and amino acid profiles of four vegetables grown on a glyphosate contaminated soil in Southwestern Nigeria

Abstract Green vegetables are examples of staple plants eating in Nigeria, and are assumed to be a well-off basis of phytochemicals and amino acids that are useful for the management and prevention of infections. However, in the farming of these vegetables, glyphosate-based herbicides (GBH (round up™)) are used as control against pests invasions which has cause reasons to be concern about their effects on the phyto-constituents present in these vegetables. In this study, we evaluated the phytochemicals constituents and amino acid profile of the leaves of Telfairia occidentalis Hook F, Amaranthus viridis Linn, Celosia argentea Linn and Cnidoscolus aconitifolius (Mill.) I. M. Johnst popular edible vegetables in Southwestern Nigeria. The vegetables seeds of these plants mentioned above were acquired from Institute of Agricultural Research and Training (IAR&T) Ibadan. And on a land designed and previously treated with a GBH (round up™) the seeds were planted and allowed to grow. A destructive method of leaves after maturation was achieved by out rightly plucking them out and air-drying under shade. Phytochemical assessments were done on milled plant samples to determine the presence of ten phyto-constituents. Centrifugation of powdered samples (2 g each) with acetonitrile at 1000 rotations per minute’s (rpm) was used to extract amino acids. Thereafter the extracts were individually spotted on a thin layer chromatography (TLC) plate and developed using the mobile phase consisting of methanol: acetic acid: water in ratio 7:2:1 v/v. The visualization for the presence of amino acids was completed by spraying the developed chromatographic plates with 0.5% ninhydrin in 2-propanol solution and observed in both day light and under the ultraviolet lamp and the retention factor (R f ).calculated for the different spots developed to determine the type of amino acids present. The assessment of phytochemicals from the four vegetables reveals the presence of alkaloids, tannins and steroids in all samples while anthraquinone glycosides, terpenoids and cardiac glycosides were absent and other phytochemicals varying in them. Ssaponins was found absent in Telfairia occidentalis and flavonoids in Cnidoscolus aconitifolius respectively. The observation of the TLC plates in daylight shows that the vegetables likely contained primary, secondary and proline amino acids while the calculation of the R f values of the TLC spots observed under an ultraviolet (UV) light indicated that amino acids found in the vegetables were methionine, tyrosine, leucine, isoleucine. However, phenylalanine was found only in Celosia argentea. The study evaluated phytochemicals and amino acids parameters in four leafy vegetables grown on contaminated glyphosate based herbicide soil and assessments shows that their medicinal properties were not altered with the minimal exposure to contaminant.

Assessment of sesquioxides status of some uplands soils in humid southwest Nigeria

Assessment of some sesquioxides in the upland soils in southwestern Nigeria was undertaken to evaluate their degree of weathering under humid tropical conditions. Samples were taken from genetic horizons of eight soil profile pits sited at different physiographic positions along two toposequences in southwestern Nigeria. The samples were analyzed for gravel content, particle size distribution, bulk density, pH, organic carbon, total nitrogen, available P, exchangeable bases, crystalline and amorphous forms of Fe and Al, using standard procedures. Sand fraction ranged from 31–76% (54.49±11.34), silt from 3–19% (10.21±3.61) and clay from 10–55% (35.3±9.7). Bulk density increased with profile depth, ranging between 1.12 and 1.64g cm-3 (1.39±0.13). The pH was low (4.2–6.1; 5.0±0.55), organic carbon content ranged from 0.75–15.99g kg-1 (5.79±3.49) with higher values in the surface horizons. Total nitrogen content ranged from low to medium (0.13–2.75g kg-1; 1.16±0.49) while available phosphorus ranged from 0.49–11.63mg kg-1 (4.30±3.57) across the horizons. Crystalline forms of Fe (Fed) and Al (Ald) ranged from 10.26–39.82g kg-1 and 0.41–1.80g kg-1, respectively while the amorphous forms (Feo and Alo) ranged from 0.41–2.60g kg-1 and 0.83–1.64g kg-1, respectively. The crystalline forms of Fed and Ald were more dominant over the amorphous forms of Feo and Alo. The argillic (Bt) horizons of pedons had significant accumulation of clay particles and free iron. The weathering indices of clay and free iron accumulation in argillic (Bt) horizons of the pedons indicated that the soils of the study area were well-drained, deeply weathered and intensely leached with few weatherable minerals available for plant uptake.

Dispersion of Trace Elements as Consequence of insitu Weathering in granite-derived Tropical Soils in Southwestern Nigeria

Trace elements composition of granite and tropical soils formed by in-situ weathering over the basement complex of Ikere-Ekiti, Ado-Ekiti and Igbrara-Odo areas of SW Nigeria is evaluated and reported. The granitoids exhibit chemical features such as is common to other granite bodies across the basement areas. The soil profiles typically have four different horizons with contrasting physical characteristics. Analytical result from ICP-MS technique revealed compositional variation along vertical direction within depth of the profiles. Trace element as average for the granite reveals low Tm (0.5 ppm), Eu (2.1 ppm), Co (5.1 ppm), Sc (7.2 ppm), Hf (7.6 ppm), Sm (12.6 ppm), and Th (30.5 ppm) values, while La (110 ppm), Ce (216 ppm), Cr (235.5 ppm), and Ba (963 ppm) show enrichments. All the soils have Sm, Eu, Th, Hf and Co contents below 10 ppm; Sc, La and Ce values fall between 10-100 ppm, while Cr and Ba contents fall between 200-1500 ppm. Variation between trace contents in granite and the derived soils as revealed along depths of the profile indicates greater mobility of Th, Sc and Ba during chemical weathering while Eu and Tm are least mobile. Pronounced compositional variation occur at relatively shallow (0-1m) depth in near surface area all the profiles.

Influence of soil texture and compost on the early growth and nutrient uptake of Moringa oleifera Lam

Influence of soil texture and compost on the early growth and nutrient uptake of Moringa oleifera Lam

Influence of tillage on soil physical properties and three varieties of sesame (Sesamum indicum L.) in Ogbomoso, southwestern Nigeria

Influence of tillage on soil physical properties and three varieties of sesame (Sesamum indicum L.) in Ogbomoso, southwestern Nigeria

Response of two cultivars of cucumber to compost and NPK fertilizers on two soils of southwestern Nigeria

Response of two cultivars of cucumber to compost and NPK fertilizers on two soils of southwestern Nigeria

Distribution of Zinc in Selected Benchmark Soils of South Western Nigeria

The Understanding of the different fractions of Zinc in soils is important to effectively manage fertilizer resources due to the low availability of Zinc in the native soil worldwide. Bioavailability, uptake of Zinc by plant and its fractions depend largely on the soil parent material, the type of chemical transformation the soil has been expose to over times and some anthropogenic intervention. This study examined five different Zn pools.The distribution of Zn in soil fractions was determined for seven selected soils of South Western Nigeria. A sequential batch extraction which had been modified was used to identify Zn fractions and were separated into: the extractable zinc (Ex-Zn), zinc associated with the carbonate (CO3-Zn), the organically bound zinc (Org-Zn), sesquioxide (Ox-Zn) and residual (Res-Zn) in each soil. Total Zn was estimated as a sum of all the pools.Result showed that Zinc fractions in the soils were in this order: extractible pool (3.8%) < organic pool (13.6%) < carbonate pool (14.8%) < sesquioxide pool (22.8%) < residual pool (45.1%). The residual pool amounts for almost half of the zinc that made up the total zinc in the soil. The distribution of zinc into these pools were determined by selected physical and chemical properties of the soil; the pH, organic carbon, clay, CEC, and phosphorus. However, soil phosphorus and pH had the highest influence on the zinc in the experimental soils. The stable fraction that dominated the soil was evident in the low extractable Zn fractions in the soil. Which is an indication of the inherently low levels of the bioavailability of Zn in the selected soils used in this study.

Status of Integrated Soil Fertility Management (ISFM) in Southwestern Nigeria

The soils of South western Nigeria are rapidly degrading due to nutrient mining, soil loss, inappropriate land use, low inherent soil fertility coupled with adverse effects of climate change. These have resulted to persistent low yields and farmers’ poverty. The current farming systems have failed to improve continuous decline in crop production. There is need for integrated approach that involves mineral fertilizer, organic resources, and improved crop varieties with sound agronomic practices if the region will be able to feed its population of over 35 million people. Integrated Soil Fertility Management (ISFM) is an all-encompassing resource management technique that embraces the use of good planting materials, with appropriate organic and/or inorganic fertilizer application or their integrated use. It also entails adapting the various combinations of the ISFM components to local conditions which by implication means site specific management. There is lack of coordinated information about the components of ISFM being used in SWN and most stakeholders have not appreciated the importance of integrated approach. This paper is therefore put forward to review the status of Integrated Soil Fertility Management in South western Nigeria in order to identify knowledge gap for sustainable crop production in the region.

Cadmium adsorption as influenced by poultry manure addition in soils of South-Western Nigeria

ABSTRACTSoil contamination with heavy metals is of great concern worldwide because of its negative effects on human health and environment. The objective of this study was to evaluate the influence of poultry manure on cadmium (Cd) adsorption characteristics in soils from ten different land uses and to determine the effects of Cd adsorption on soil properties. Laboratory experiments were carried out using Cd concentrations ranging from 0 to 160 mg Cd L−1 and poultry manure rates ranging from 0 to 8% w/w basis. Results showed that all the soils exhibited varying capacity to adsorb Cd with values ranging from 28.78 to 130.2 mgkg−1; 126.2 to 153.5 mgkg−1 and 126.2 to 156.1 mgkg−1 for 0%, 4% and 8% poultry manure at 160 mgkg−1 initial Cd concentrations, respectively. Lowest Cd adsorbed (28.78 mgkg−1) was recorded in samples from 6 months fallow and highest (156.1 mgkg−1) from vegetable field. On the average, capacity to adsorb Cd was 72.1%, 99.7% and 95.3% with 0%, 4% and 8% applied poultry manure, respectively. Organic carbon, CEC, pH were significantly correlated with Cd adsorption. Poultry manure use will increase Cd adsorption and decrease Cd in the environment.

The Effect of Poultry Manure and P Fertilizer on Some Phosphorus Fractions in Some Soils of Southwestern Nigeria: An Incubation Study

ABSTRACTAn incubation experiment was conducted in the laboratory for 10 weeks to study the changes in some phosphorus (P) fractions in two soil series. Poultry manure was applied at 0, 5, 10, 15, and 20 t ha−1 solely and in combination with single superphosphate (SSP) at 0, 15, 30, 45, and 60 kg P ha−1. Significant increases in all the P fractions were observed to the 6th week of incubation (WAI). Sole application of poultry manure was, however, effective in reducing P occlusion in the two soil series used. An increase in Fe–P which was the largest extractable inorganic P was observed with the application of 10 t ha−1 of poultry manure and 30 kg P ha−1 of SSP in the Iwo series and combination of 20 t ha−1 of poultry manure and 45 kg P ha−1 of SSP in the Alagba series.

Potassium Fixing Capacities of Some Selected Soils in South Western Nigeria

Potassium Fixing Capacities of Some Selected Soils in South Western Nigeria

Magnesium Adsorption in Selected Cocoa Growing Soils Within Southwestern Nigeria

Magnesium is one of the vital nutrients required by Theobroma cacao L. for optimum growth and yield. Several authors have reported the deficiency of magnesium in Nigerian cocoa plantations and ended up recommending the application of magnesium fertilizer based on agronomic soil test. Application of fertilizer without considering the potential of each soil to retain certain proportion of the applied fertilizer will lead to reduced available Mg in the soil solution. The study was carried out to evaluate the sorption capacity of selected cocoa growing soils in southwestern Nigeria. Soil samples were equilibrated with 20, 40, 60, 80 and 100 mg Mg L. Result showed that, Freundlich equation best described the adsorption of magnesium onto the soil surfaces. Adsorption of magnesium was highest in Owena soil. Hence, more magnesium fertilizer will be required by Owena soil compared with Ekiti, Ibadan, Ile-Ife and Bodo soils to produce equal amount of available magnesium ions in soil the solution.

Assessment of Dithionite and Oxalate Extractable Iron and Aluminium Oxides on a Landscape on Basement Complex Soil in South-Western Nigeria

The study investigats the morphological, physical and chemical characteristic of a toposequence on basement complex in Ejioku area, south-western Nigeria on latitude 07°28.675'N; and longitude 004°07.219'E; 180 m above sea level at the upper slope. It terminates at the valley bottom on latitude 07°28.756'N; and longitude 004°07.229'E; 175 m above sea level. The topography of the site is moderately slope (not greater than 10%). The aim is to examine the two forms of sesquioxides (crystalline-dithionite extractible Fe & Al and amorphous-oxalate Fe & Al) and their distribution on the toposequence. The crystalline form of Fe oxide dominates all the positions and ranges from 7.2 g/kg at the valley bottom to 444.3 g/kg at the crest compared to the amorphous forms that range from 2.7 g/kg to 10.9 g/kg. The crystalline and amorphous aluminium oxide contents of the soils are low (2.9 g/kg - 43.3 g/kg and 1.3 g/kg - 8.7 g/kg respectively). There is significant negative relationship between Fed and Fed/Feo (r =-0.15; P n = 16). There is also a correlation between Feo and Ald (r = 0.63; P n = 16), FeO and FeO/Fed (r = 0.44; P n = 16), signifying a high level of weathering. The relatively high amount of Fed virtually at all the horizons indicates that the crystalline and less active forms of the oxides exist more on the landscape and may be responsible for the non-availability of some nutrient like phosphorus that may be sorbed to their crystals lattice. All forms of Al in the soils are low especially, the oxalate extractable forms, when compare with the dithionite extractable forms. However, there is a significant correlation between Ald and Feo/Fed (r = 0.57; P

Activity of β-Amylase in Some Fungi Strains Isolated from Forest Soil in South-Western Nigeria

Aims: The aim of this study was to isolate fungi species from Omo natural forest soil in Ogun State of Nigeria and study the amylases from the fungi species which are digestive enzymes that hydrolyze glycosidic bonds in starch to glucose, maltose, maltotriose and dextrin; and in particular determine the activities of β-amylase from the forest soil. Study Design: Nine different species of fungi were isolated from the Omo natural forest reserve soil (Gonatobotrrys simplex, Aspergillus niger, Spiromyces minutus, Aspergillus flavus, Articulospora inflata, Botrytis cenera, Penicillium italicum, Aspergillus fumigatus and Aspergillus flavus). Four species of the fungi (Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus and Penicillum italicum) exhibited amylolytic activities maximally were obtained and screened for the production of beta-amylase (1,4-α-D-glucan maltohydrolase) for five days in liquid medium using 2% starch as carbon source. All the strains of fungi produced β-amylase optimally within the first 24 hours with progressive decreased production as the days gone by. Place and Duration of Study: Department of Biochemistry, Federal University of Technology, Akure, Ondo State, Nigeria, between February 2010 and March 2011. Methodology: We isolated many fungi species from forest reserve soil, four species Original Research Article British Biotechnology Journal, 4(1): 1-9, 2014 2 (Aspergillus flavus, Aspergillus niger, Aspergillus fumigantus and Penicillum itallicum) were identified and assayed for β-amylase activity. Results: All the organisms produced β-amylase activity favorably at 40oC; all were observed to be thermally stable at between 30oC and 40oC with optimal pH in alkaline medium between pH 7.00 and 9.00. Conclusion: The results obtained in this study however showed that all the fungi strains are promising sources of β-amylase for potential applications in food and pharmaceutical industries and for biotechnological and industrial applications.

Heavy metals concentration levels in selected arable agricultural soils in South Western Nigeria

The application of micronutrient supplements such as fertilizer, animal manure and sewage sludge in bid to enhance soil productivity and crop yield, poses the risk of heavy metals elevation and nutrients depletion in arable lands. Arable soils were collected from farmlands in use for the cultivation of food produce in selected farming communities in South Western Nigeria. The soils were air-dried, sieved to give <2 mm grain size and digested according to standard methods. The concentrations of Lead (Pb), Cadmium (Cd), Zinc (Zn) and Copper (Cu) were measured using flame atomic absorption spectrophotometer (FAAS). The concentration of Zn ranged from 12.98 to 38.94 µg/g, and was the highest amongst the measured heavy metals. This was followed by Cu, 6.17 to 20.87 µg/g and then Pb, 0.79 to 8.35 µg/g, while the concentration of Cd, 0.26 to 5.75 µg/g was the least. Geo-statistical analysis on the concentrations of the measured heavy metals revealed a significant (p < 0.05) spatial correlation (γ) with the soil pH and organic carbon (OC) (Pb, γ = 0.74; Cd, γ = 0.67; Zn γ = 0.57; Cu, γ = 0.52) and (Cd, γ = 0.79; Zn γ = 0.59; Cu γ = 0.51), respectively. The OC levels predispose soils to the retention of soil heavy metals and micro/macro-nutrients depending on the nature of OC-metal interaction. The concentrations of the heavy metals were below the European Economic Community (EEC) maximum allowable concentrations (MACs) in agricultural soils, except for Cd. About 56% of the farmland soils contained more than 3 mg/kg of Cd, while about 44% were within the 1 to 3 µg/g EEC MAC for Cd in agricultural soils. Although, the concentration levels of the measured heavy metals in the soils do not appear to be of serious concern, the study results provides evidence of gradual accumulation of Cd in farmlands Key words: Heavy metals, arable agriculture, farmland, micronutrient supplements, concentration.

Faunal population as parameter for soil fertility assessment: a case of soil microarthropod study in South-Western Nigeria

The fertility of most tropical soils depends on the level of its organic matter which serves as the reservoir for most plant nutrients and food for organisms in the topsoil. Soil fauna plays a major role in the transformation processes by which plant nutrients are released from soil organic matter. Most of the soils in south-western Nigeria are dominated by low activity kaolinitic clay, generally low in plant nutrient buffering capacity, and easily depleted. As biological property of the soil, faunal population have not been greatly related to the chemical properties and explored as parameter in assessing the fertility of the soil. Though soil microarthropod populations are comparatively lower in tropical soils, the few studies on this group of soil fauna has demonstrated their significant influence on the rates of nutrient turnover. Studies aimed at determining relationships between microarthropod taxa and soil fertility parameters in south-western Nigeria reveal their potential in management of soil for sustainable crop production. In a study involving soils from eight different land-use management, microarthropod population correlated with soil organic carbon, available P and exchangeable cations, and nutrient uptake depending on their taxa. Results also indicated that microarthropod activity could influence P sorption characteristics of the topsoil.

Potential of on-farm produced compost and organic amendments in soil fertility management for organic maize production in southwestern Nigeria

Soil fertility is central to organic crop production in the low activity soils of southwestern Nigeria. Studies on the use of organic amendments in the management of soil fertility and productivity have indicated the potential of organic practices in this region. In an experiment to study the effects of 5, 10 and 15 t ha−1 of composted pig manure on soil organic matter (SOM) and nutrient dynamics, compost was applied in 2005 and 2006 while land was left fallow in 2007. Parameters observed include aggregate stability, SOM fractions and N mineralization (laboratory and field incubation). Macroaggregate stability indices increased with compost rates. Distribution of SOM fractions, which accounted more for aggregate stability than total organic carbon with time, was better in compost-treated cultivated land compared to adjacent grassland. Nitrogen mineralization was highest with 10 t ha−1 of compost in both years. Soil chemical properties and nutrient uptake of maize after fallowing also showed that 10 t ha−1 of compost was most effective. Observations from another study involving green manure, compost, organo-mineral and mineral fertilizers have also demonstrated significant effects of organic amendments on soil fauna and other properties compared to mineral fertilizer even in the short run without yield compromise.

Evaluation of Soil/Material Interface Friction and Adhesion of Akure Sandy Clay Loam Soils in Southwestern Nigeria

There is the need to develop appropriate and efficient soil engaging tools and implements to optimize energy required to cultivate the land and enhance agricultural productivity and sustainability in Nigeria. Necessary design data which were hitherto scarce for Nigerian soils are therefore required to accomplish the task effectively. Laboratory investigations were carried out to evaluate angle of soil/material friction and coefficient of soil/ material friction necessary in the design of soil-engaging tools and implements. Facilities used in the investigation include soil-material friction device or sliding shear apparatus. Three types of soil investigated were sandy clay loam soils. The structural materials’ surfaces investigated were rubber (RUB), steel (SST), galvanized steel (GAS) and Teflon (TEF). Results show that the coefficient of soil/material friction increased with moisture content to a limit and thereafter decreased. For the materials tested the range was 0.13 - 0.85 in the three soil textures and can be described by polynomial equations for the purpose of prediction. Rubber had the highest coeffi cient of soil/ interface friction followed by smooth steel, galvanized steel, while Tefl on had the least in that order. Key words : Soil; Coeffi cient of friction; Materials; Soil/ tool interface; Adhesion; Models

The physical properties of some soil profiles and management of an erosion prone soil in southwestern Nigeria

Infiltration, ease of root penetration, retention of plant nutrient, availability of water within crop rooting zone and soil proneness to erosion are all intimately connected with the physical properties of the soil. A study was conducted within the Teaching and Research Farm of University of Ibadan, Western Nigeria to investigate the physical properties of an erosion prone soil. Three profiles were dug along a 60 m toposequence and core samples collected at depth of 0 - 7 cm, 8 - 15 cm 15 - 45 cm, 45 - 75 cm and 75 - 105 cm. The textures of the subsoil were; sandy clay, sandy clay loam or sand. This light texture indicates that the soil is highly susceptible to degradation by human and animal agents. Clay content increased down the profile whereas fine sand fraction distribution was uniform along the toposequence. The soil bulk densities values ranged from 1.65 - 1.83 g cm-3. Total porosity values where low (< 40 %) indicating that the soil is ‘unsatisfactory’ for crop production. The soil hydraulic conductivity class was the “very slow” type except at the upper slope which was moderate. This “very slow” conductivity nature of the soil could cause water deficit in crop rooting zone and build up runoff with little rainfall or irrigation. This implies the soil is susceptible to erosion. Variability of bulk density was low (CV < 15 %), whereas that of gravel, clay fractions and hydraulic conductivity were consistently high (CV > 35 %). Coarse and fine sand fraction were consistently moderately variable (CV = 15 - 35 %). Minimum tillage will offer great advantage when combined with surface mulch. Strip cropping, use of fertilizer of organic origin and cover crops will improve organic matter of the soil, soil stable aggregates, soil porosity and infiltration. Uniform soil management along this toposequence should be avoided.Key words: Binders, processing, water stability.