FACULTY OF AGRICULTURE
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Item Survey of biodegrading agents in logs and planks in selected sawmills and timber markets in Ibadan Oyo State(Forestry Association of Nigeria, 2015) Omole, A. O.; Adegeye, A. O.; Jemide, O.Biological deterioration of wood is one of the major challenges on wood utilization especially in tropical countries like Nigeria. This is because of the favourable weather condition for the bin-deteriorating agents to thrive. This study is therefore carried out to investigate the biodegrading agents of logs in sawmills and planks in plank markets in Ibadan, Nigeria. Data for the study were collected using checklist, and laboratory examination of collected samples from decayed logs and planks. The data obtained were subjected to descriptive statistics. The results of the laboratory examination revealed that a variety of fungi moulds, namely Aspergillus flavus Fredrick Link, Aspergillus niger VanTieghem, Botryodiplodia theobromae Pat, Trichodermalongi brachlatum Rifai, Penicillium oxalicum Currie and Thorn, Rhizopus stolonifer,(Ehrenb.ex Fr)., that are not host specific were encountered. Botryodiplodia theobromae Pat, was present in all the three sawmills and two timber markets while Aspergillus flavus Fredrick Link and Aspergillus niger VanTieghem, were present in only one sawmill (Moniya). The order Coleoptera and Isoptera were the two prominent insect pest groups identified. These were from seven families out of which five species of insects namely Termites, Beetles, Borers, Weevils and Carpenter ants were identified. The degree of molds growth on the surface of the wood is an indication that the conditions are favourable for wood decay to occur. It is therefore recommended that logs should be properly handled during log storage and processing in the mills by keeping the environment clean. Processed timbers should also be arranged in such a way that there will be free flow of air within stacked timber.Item Assessment of variation in the fiber characteristics of the wood of vitex doniana sweet and its suitability for paper production(2014-03) Ogunjobi, K. M.; Adetogun, A. C.; Omole, A. O.The study investigated the fibre characteristics and chemical composition of Vitex doniana towards determining its potentials for pulp and paper. Fibre dimensions are of great importance because of the strong correlation between it and the strength properties of wood and paper. Axial and radial examinations of fibre characteristics of naturally grown wood of Vitex doniana were investigated to determine its suitability for paper production. Wood slivers were prepared from slices, introduced into wash bottles containing equal volume (1:1) of glacial acetic acid and 30% hydrogen peroxide and investigated on a Rheichert Visopam microscope. Variations existed in the axial and radial direction of the wood. The mean values of fibre characteristics are: fibre length (1.48mm), fibre diameter (21.9μm), fibre lumen width (12.7μm) and fibre wall thickness of Vitex doniana was 4.9μ. The mean lignin, cellulose and extractive contents were 28.1%, 41.2% and 3.5% respectively. Based on the derived values: Slenderness ratio, flexibility coefficient and Runkel ratio, species of Vitex doniana were considered to be good paper making materials.Item Variations in the wood properties of Terminalia mantaly (H. Perrier) grown as municipal tree in a Nigerian university(Forest and Forest Products Society, 2014) Omole, A. O.; Moshood, A. J.A study was carried out b investigate wood properties of Terminalia mantaly (H. perrier), one of the municipal tree species in University of Ibadan, Ibadan. Materials for the study were obtained from four of the urban trees in the University campus. Test samples were collected at four different levels along the height and dial positions with the test specimen prepared in accordance with standard test procedures. Prepared samples were subjected to some physical and mechanical property tests. The selected physical properties were Moisture Content (MC), Specific Gravity (SG) and Volumetric Shrinkage (VS). The mechanical properties (Modulus of Rupture, MOR; Modulus of Elasticity, MOE and Impact bending, IB) were determined in accordance with the British Standard BS373 (1989), Data generated were subjected to statistical analysis. The overall mean SG, MC and VS for the species were 0.797, 39.82% and 46.52%, respectively while the mean MOR, MOE and IMB were 62.94N/mm2,5056N/mm2 and 404.81, respectively, It was evident that variations exist in both the radial directions and sampling heights for all the selected trees. Findings revealed that Terminalia mantaly is a strong wood with gaud quality, making it a potential material for load bearing and other construction work.Item Effect of shelling ratios on the sorption and flexural properties of cement bonded particleboard produced from mixed Nigerian hardwood species(Forest and Forest Products Society, 2014) Badejo, S. O.; Omole, A. O.; Fuwape, J. A.Panel layer characteristics, otherwise referred to as shelling ratio, relate to the proportional ratio between the thickness of the fine surface layer and flake core layer materials in a 3-layered particleboard. The experiment was carried out in order to determine the most favourable core-surface thickness ratio at which board properties are maximized. To achieve this, experimental cement-bonded particleboards were made using three sawdust surface/flake core layer thickness ratios d 1 : 2, 1 : 1 and 2 : 1. Each of the ratio was considered at two board density IeveIs of 1100 and 1200 kg/m3 and two cement/wood mixing ratio of 2.25 : 1.0 and 2.75: 1.0. The experimental arrangement is a three-factor factorial experiment which manifested in 12 treatment combinations. The experimental boards produced were subjected to modulus of rupture (MOR), modulus oSf elasticity (MOE), water absorption (WA), thickness swelling (TS) and linear expansion (LE) tests. Data collected were subjected to statistical analysis using ANOVA and multiple linear regressions. The mean Moduli of Rupture and Elasticity (MOR and MOE) obtained ranged from 4.23 to 11.92 N/mm2 and 1950 to 4140 N/mm2 respectively. Water absorption (WA) and thickness swelling (TS) ranged from 24.75 to 10.58% (WA) a d 0.41 to 4.01% (TS). It noted that the mean values of MOR and MOE obtained at the sawdust surface layer/flake core layer thickness ratio of 1 : 2 were significantly superior at 5% level of probability to those obtained at the thickness ratio levels of 1 : 1 and 21.1. On the other hand however, the mean values of WA and TS obtained at the sawdust surface layer/flake core layer thickness ratio of 2 : 1 were significantly superior at 5% level of probability to those obtained at thickness ratio levels of 1 : 2 and 1 : 1. of sawdust to flake contents of board. The highest strength and stiffness values obtained at the thickness ratio level of 1 : 2 of sawdust surface layer flake core layer notwithstanding, the thickness ratio level of 2 :1, which implies cement-bonded particleboard production at increased sawdust content and decreased flake content, was selected applied as a the optimum. This being so, in view of the fact that the overriding objective of the study was to 6 mm thick cement-bonded particleboards which could be resistant to moisture and adequate for house ceiling.Item Sorption and bending properties of wood cement panels produced from mixed Nigerian hardwoods at varying water/cement ratios(2013-07) Badejo, S.O.; Omole, A. O.The study was carried out to investigate the influence of water/cement ratio on the moisture response and mechanical properties of wood cement panels fabricated with mixed hardwood species. The experimental boards so produced were subjected to modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), thickness swelling (TS) and linear expansion (LE) tests. Data collected were subjected to statistical analysis using ANOVA and multiple linear regressions MOR and MOE ranged from 4.94 N/mm2 to 11.63 N/mm2 and 2340 N/mm2 to 4880 N/mm2 respectively. Strength (MOR) and stiffness (MOE) of the boards increased as water/cement ratio was raised from 0.50 to 0.60. With these ranges, more dimensionally stable cement-bonded particleboards were obtained. As water/cement ratio was however raked from 0.60 to 0.65, weaker and inferior boards were produced. The results of the multiple regression analysis showed that water/cement ratio (WCR), cement/wood mixing ratio (MR) and board density (BD) were positively correlated with MOR and MOE. Water absorption (WA), thickness swelling (TS) tests ranged from 16.27 to 48.82% and 0.49 to 2.30% respectively, Statistical analysis of the results showed that the process variables WCR, BD and MR were significant at 1% level of probability on WA and TS. Moiture uptake and swelling of .the panel decreased as water/cement ratio was raised from 0.50 to 0.60. Inferior panels were produced when water/cement ratio was increase beyond 0.60. Therefore 0.60 was considered uptimum level for board fabrication in this study.Item Seasonal variation in litter fall an age series gmelinaarborea plantation in a Nigerian rainforest(2013-01) Ogunyebi, A. L.; Omole, A. O.; Bada, S. O.Monthly variation in litterfall of Gmelinaarborea stands aged 28, 29, and 30 years were studied for 13 months in 2005 - 2006 with litter traps in three 20m x 20m plots randomly selected in Gmelinaarborea stands in Shasha Forest Reserve (SFR),Osun State, Nigeria. Monthly collections of litter fractions per stands were sorted into leaves, twigs, reproductive structures and others. Litters according to fractions per stand per month were oven dried at 80°C for 48 hours. Samples were created for chemical analysis. Data collected were analyzed using descriptive statistics and inferential at 0.05 level of significance. Litterfall (especially leaf fall) occurred throughout the period of collection (13 months) in the stands (S). The peak of total litter fall was recorded in October 2005 in S1(18.2%) while peaks were recorded in September of same year in S2 (11.21%)and S3 (13.67%). The analysis of variance to determine interaction effect between fall of the litter fractions and age of the stands did not show any significant differences. Leaves constituted the bulk of litter fall across the three stands. The percentage of leaf litter to the total litter per hectare in stand ages 28, 29 and 30 years were 41.32, 34.19 and 24.48% respectively, while the contribution of unidentified litter thrash was highly insignificant.Item Investigation of pulping potentials of jatropha curcas(2013-10) Ogunjobi, K. M.; Adetogun, A. C.; Soetan, D. O.; Omole, A. O.; Olorunfemi, O.; Odebiyi, J. B.The study investigated the pulping potentials of Jathropha curcas, Samples of sawdust, shaving and splinters were taken at three sampling heights (20%, 50% and 90%) and macerated using glacial acetic acid (CH3COOH) and hydrogen peroxide (H2O2) in ratio 1:1. Result of fibre characteristics showed that mean fibre length ranged from 0.216mm at top 0.243mm at middle and 0.244mm at the base. Mean fibre diameter of sawdust (0.01053mm) was highest followed by 0.01028mm for splint and shaving had 0.01002mm. Highest lumen width was recorded at top. Both sampling height and within sample exhibited. Runkel ratio of less than 1 while Flexibility coefficient compared favourably with other species. This study showed that Jatropha stem can be used as an alternative in pulp and paper industry taking advantage of its appreciable short fibre length and Runkel ratio of less than 1.Item Relationship between mechanical properties of vitex doniana, a lesser known species and implications for utilization(2013) Ogunjobi, K. M.; Adetogun, A. C.; Omole, A. O.; Owoeye, S. O.; Odebiyi, J. B.Relationship between the mechanical properties of Vitex doniana, a lesser known wood species was investigated towards determining its potentials for utilization. Four trees obtained from the free area of Olokemeji Forest Reserve, Ogun State, Nigeria were sampled at butt (50cm above the ground) and at 10%, 30%, 50%, 70% and 90% of merchantable height (MH) The samples were also partitioned into corewood, middlewood and outerwood. Impact Bending (IMB), Modulus of Rupture (MOR), Modulus of Elasticity (MOE) and Maximum Compressive Strength Parallel to Grain (MCS//) were determined. Relationship between the mechanical properties was determined using regression equation. Results showed that Mean IMB, MOR, MOE and MCSS// were 0.69m, 85.4 N/mm2, 6380N/mm2 and 40.8N/mm2 respectively. The best relationship existed between IMB and MCS// (R2 = 0.75) followed by between MOR and MOE (R2 =0.71) while the least relationship (R2 = 0.43) existed between MOR and MCS//.Item Influence of flake thickness on flexural and moisture properties of wood cement panels fabricated from mixed furnish of eight hardwood species(Faculty of Agric and Forestry, University of Ibadan, 2012) Badejo, S. O.; Omole, A. O.The study was undertaken to investigate the influences of flake thickness on physical and mechanical properties of wood cement panel produce from mixed hardwoods species. The properties investigated are modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), thickness swelling (TS) and linear expansion (LE) of the experimental cement-bonded particleboards. Both the moduli MOR and MOE of specimens were calculated as specified in the ASTM Standard No D-1037 of 1978. MOR and MOE ranged from 6.04N/mm2 to 11.96 N/mm2 and 3110N/mm2 to 5060 N/mm2, respectively. Flake thickness had a significant effect on MOR and MOE at the 5% and 1% level of significance, respectively. Both cement/wood ratio and board density had a significant effect on MOR at the 1% level. Flake thickness was negatively and linearly correlated with MOR and MOE: On the other hand, cement/wood mixing ratio and board density were positively and linearly correlated with MOR and MOE. WA and TS tests for the study ranged from 34.60 to 44.04% and 0.57 to 1.61%, respectively. Analyses show that flake thickness, cement/wood mixing ratio, and board density had significant effects on WA and TS at the 1% level of significance. Results showed that WA and TS of the experimental panels increased as the thickness size of the particles increased from 0.250 to 0500mm.Two-way or three way significant interactions were not found to be significant between and among the three production variables applied in the experiment. The thinner the flakes used in board production, the stronger; stiffer and more dimensionally stable the cement-bonded particleboards.Item Effectiveness of bioengineering methods of water erosion control in Tarka valley versant , Niger Republic(Ecological Society of Nigeria, 2012) Omole, A. O.; Oumarou, A.Erosion problem is recognized as a serious threat to human beings, forestry and agricultural activities in the rural areas of Niger Republic. The effectiveness of three Bio-engineering methods of water erosion control in the degraded land of two villages in Bouza local government area, of the Niger Republic was assessed. These two villages are highly susceptible to water erosion. The three methods of erosion control used were wall of stone, Trench and Demi-Lune. Trees and herbaceous plants were then introduced to the reclaimed land to green up the environment. After generation, data collected include rate of soil cover by herbaceous vegetation, inventory of woody and herbaceous vegetation, stand density and the survival rate of planted trees. Result showed high biomass production and great density of herbaceous species of different families with the highest species frequency being Gramineae. The total biomass production for the two sites was estimated at about 413.15 and 461.12 tons for Babarangua and Kougouptache respectively. Statistical analysis showed that the site has no significant influence on biomass production while the technique adopted exhibit significant influence on production at the same level of probability. The wall of stone technique gave the best result in herbaceous production while the trench and Demi-lune technique ensure good rate of tree survival for the planted trees. The three methods were effective in erosion control in two sites.