Journal of Agricultural Engineering and Technology (JAET)
The main aim of the Journal of Agricultural Engineering and Technology (JAET) is to provide a medium for dissemination of high quality Technical and Scientific information emanating from research on Engineering for Agriculture. This, it is hoped will encourage researchers in the area to continue to develop cutting edge technologies for solving the numerous engineering problems facing agriculture in the third world in particular and the world in general. The Journal publishes original research papers, review articles, technical notes and book reviews in Agricultural Engineering and related subjects. Key areas covered by the journal are: Agricultural Power and Machinery; Agricultural Process Engineering; Food Engineering; Post-Harvest Engineering; Soil and Water Engineering; Environmental Engineering; Agricultural Structures and Environmental Control; Waste Management; Aquacultural Engineering; Animal Production Engineering and the Emerging Technology Areas of Information and Communications Technology (ICT) Applications, Computer Based Simulation, Instrumentation and Process Control, CAD/CAM Systems, Biotechnology, Biological Engineering, Biosystems Engineering, Bioresources Engineering, Nanotechnology and Renewable Energy. The journal also considers relevant manuscripts from related disciplines such as other fields of Engineering, Food Science and Technology, Physical Sciences, Agriculture and Environmental Sciences. The Journal is published by the Nigerian Institution of Agricultural Engineers (NIAE), A Division of Nigerian Society of Engineers (NSE). The Editorial Board and NIAE wish to make it clear that statements or views expressed in papers published in this journal are those of the authors and no responsibility is assumed for the accuracy of such statements or views. In the interest of factual recording, occasional reference to manufacturers, trade names and proprietary products may be inevitable. No endorsement of a named product is intended nor is any criticism implied of similar products that are not mentioned. Submission of an article for publication implies that it has not been previously published and is not being considered for publication elsewhere. The Journal’s peer review policy demands that at least two reviewers give positive recommendations before the paper is accepted for publication. Prospective authors are advised to consult the Guide for Authors which is available in each volume of the Journal.
The consequence of dam failure could be catastrophic depending on the magnitude of the failure and downstream properties. The overall objective was to estimate the dam break outflow hydrograph, route the dam break hydrograph through the downstream valley and floodplain and then estimate the inundation levels. It is therefore required to carry out dam break analysis that will help in devising appropriate management strategies and mitigate the impact effect of such disaster. The dam break analysis of the University of Ilorin dam was studied with HEC-RAS model in conjunction with Geographic Information System (GIS) and HEC-GeoRAS. HEC-GeoRAS was used to extract geometric information from a digital terrain model and then imported into HEC-RAS. The Steady and unsteady flow simulation of the dam break event was performed using HEC-RAS and results were mapped using GIS. The result showed that area immediately after the bridge (about 456.66-607.40 m downstream from the inline structure) and the tail end of the river reach (about 1.3 to1.6 km downstream from the inline structure) will experience greater impact of the flood for the maximum water surface profile from flood inundation. The largest flow area covered between the dam and the bridge is 1,873.8
PREDICTION OF TOMATOES FRESHNESS USING INFRARED THERMOGRAPHY
The importance and benefits of Infrared thermography has been extended beyond industrial applications and now found more usefulness in different areas of agriculture, especially in predicting the quality of harvested produce. In Africa, Tomatoes consumption is very high as most African delicacies are incomplete or cannot be processed without the use of tomatoes. However, the authenticity in terms of quality and safety of the highly consumed tomatoes is subject to doubt. This problem is compounded by lack of fast and appropriate technologies to predict quality of agricultural produce. Fresh samples of Roma VF tomatoes (150 samples) seen to be free from any physical defects were acquired from three different vegetable markets in Ile-Ife, Nigeria to compare the level of freshness of the tomatoes available for consumption. The thermograms of the samples were taken using a FLIR T200 Infrared Camera. The thermograms were captured on the day the tomatoes were purchased (1) and thereafter every 24 hours for 5 consecutive days under a standard room temperature storage-condition. Thermograms were analyzed with a quick-report FLIR software. The result of the analysis at day 1 shows that 80% of the tomato samples had anomalies with a mean minimum temperature of 30 ºC and classified not as fresh as physically justified. The defected samples deteriorated faster than the remaining 20% without any noticeable anomaly that were classified fresh with a mean minimum temperature of 32.2 ºC. The fresh tomatoes were observed to have an extended shelf life and therefore recommended for consumption until after five days of storage when their mean temperature dropped below 31ºC. This study showed that infrared thermography is appropriate for tomatoes quality assessment as against visual inspection. Thermography is thereby presented as suitable in building a fast online system for predicting deterioration rate in tomatoes and other perishable food produce.
MODELLING THE EFFECT OF SOIL COMPACTION ON THE GROWTH OF MAIZE AND COWPEA IN HUMID TROPICS
During agricultural operations such as bush clearing, soil preparation, planting, and crop harvesting the soil is subjected to high compaction stresses. However, the magnitude of stress-induced on the soil by agricultural machines and its impact on plant growth is seldom studied, especially in the humid tropics. Firstly, this study performed laboratory experiments to investigate the growth response of Zea mays and Phaseolus vulgaris planted on loam-clay and loamy sand soils compacted at different levels, and secondly, numerical simulation was performed using PLAXIS 2D (soil modelling software) to determine the stress propagation in the soil due to vehicular loading. The soils were compacted at the following levels: 0 (control), 5, 10 and 15 blows using the modified standard proctor hammer (4.54 kg). Following soil compaction, there was up to 70% reduction in the permeability of the loam-clay soil from 6.89 ×10−5 cm s-1 (control) to 2.01 ×10−6 cm s-1 (15 blows). The plant height, biomass and root density all reduced due to soil compaction. There was a significant difference between the root weight due to the different compaction levels and soil type (p-values < 0.001). Generally, on both the loamy clay and loamy sand soils there were apparent signs of compaction stresses on the leaves of the Zea mays and Phaseolus vulgaris, making the plant leaves pale in colour and pancake-like. The result from the numerical simulation show that the stress distribution in the soil due to vehicular loads increases with increase in the void ratio of the soil. There was a higher concentration of the effective stress at the midpoint (i.e., directly under the wheel) of the tyres compared to the stresses in between the axles; with a maximum of 107.53 kPa, 101.67 kPa, 87.49 kPa, 79.19 kPa, 72.31 kPa for 0.1, 0.3, 0.5, 0.7 and 0.9 soil void ratios, respectively for the front axle. Rear tyres transmit more stress to the soil compared to the front tyres. It is concluded that soil compaction changes soil structure by increasing bulk density, penetration resistance and decreasing the total porosity of the soil, with negative consequences to crop growth and development.
MODELING AND OPTIMIZATION OF PROCESS CONDITIONS AND SOME NUTRITIONAL QUALITIES OF DRIED TOMATO USING RESPONSE SURFACE METHODOLOGY
Tomato fruits are seasonal and highly perishable due to high moisture content, thereby making the preservation difficult. Drying is one of the ways to preserve the nutritive qualities of the product. In this research, optimum temperature and time necessary for drying tomatoes using a response surface approach were studied. Central Composite Rotatable Design (2 × 5) was adopted. Drying temperatures and time selected were 50, 55, 60, 65 and 70oC; 16, 17, 18, 19 and 20 hr, respectively. The protein, fat, ash, carbohydrate and fibre contents as well as the calorific values of the dried tomatoes were determined. Four different models were used to analyze the nutritional qualities of the dried tomatoes and the models were fitted to the experimental data using Design Expert Software. Data analyses were done using multiple linear regression at p = 0.05. Predicted optimum conditions were validated using experimental values. It was observed that drying temperature and time affected the nutritional qualities of the samples. Protein content ranged from 0.70-6.48%, fat content ranged from 2.50-9.50, ash content ranged from 9-17%, carbohydrate content ranged from 68.12-81.22, fibre content ranged from 0.50-1.50 and the calorific value ranged from 348.50-397.00 kCal. The predicted optimal values were 5.68% protein content, 7.62% fat content, 15.47% ash content, 72.61% carbohydrate content, 0.92 fibre content and 370.30 kCal calorific value at drying temperature of 55oC and drying time of 17 hrs with a desirability of 0.56. Under these optimal conditions, the experimental values were 5.36% of protein content, 7.50% fat content, 15.00% ash content, 71.14% carbohydrate content, 1.00% fibre content and 333.50 kCal calorific value. The deviations between experimental and predicted values were low and statistically insignificant which implies that the various models selected could actually predict the nutritional qualities of the dried tomatoes.
SOME PHYSICAL PROPERTIES OF DRIED TYMPANOTOSUS FUSCATUS AND PACHYMELANIA AURITA PERIWINKLE MEAT
Periwinkle serves as food mostly among people in coastal areas in Nigeria, making it an essential ingredient in preparing various delicacies. The processing of periwinkle has been through traditional methods by using a knife and needle to extract the meat from its shell. Traditional periwinkle processing is tedious, hazardous, time-consuming, unwholesome, and uneconomical. This study determines the effect of drying methods (cabinet and oven drying) on the physical properties of periwinkle types. The intention is to help solve the challenges of machine designing, processing, handling, and storing periwinkle. The periwinkle meat samples were dried using the cabinet and oven drying methods. The drying of the two varieties of periwinkle meat samples (Tympanotosus fuscatus and Pachymelania aurita) was at about 105ºC for 3 hours in an electric oven dryer. The ambient temperature during oven drying was 31ºC, and the ambient relative humidity of 57%. While using the cabinet dryer, the temperature was at about 60ºC for 10 hours, with ambient temperature and relative humidity at 33.3ºC and 61%, respectively. Some dried periwinkles were selected from the samples to determine the geometrical and gravimetric properties of the two periwinkle varieties. The ANOVA results showed a significant difference (p<0.05) in the physical properties of the varieties between the fresh sample, oven-dried, and cabinet-dried samples. Hence, oven and cabinet drying methods are recommended for appropriate drying of the periwinkle meat before storage. The determined physical properties from the study can be used as input parameters for designing efficient processing equipment for periwinkle meat.
DEVELOPMENT AND PERFORMANCE EVALUATION OF COCOA-BEANS ACTIVE SOLAR CABINET DRYER PRIMED WITH SOLAR CELLS
Farmers in the rural areas commonly preserve biomaterials by open sun drying. However, this method is associated with problems mostly long drying period, low quality dried products, large drying area. Active direct mode solar cabinet dryer primed with solar cells was developed and tested with cocoa-beans. The cocoa bean samples were dried both in the solar dryer and in open sun drying at layer thickness of 40 mm. Purposive sampling technics and simple descriptive statistics were adopted in identifying the drying layer thickness farmers’ normally dry cocoa beans. Heat generation from the dryer was limited to solar energy availability. Solar radiation, ambient relative humidity, wind speed and temperature were common environmental conditions, the drying samples were exposed to. The solar dryer raised the drying temperature from average ambient air temperature of 31.8 0C to average drying air temperature of 43.5°C. Result showed that 200 % drying time was saved when compared with open sun drying method. The analysis also, revealed that the drying efficiency of the solar active dryer was 55% while that of open sun drying was 18%. The drying rate of cocoa-beans samples dried in the solar dryer and open sun drying was 1.4x10-4 kg/s and 4.5 x 10-5 kg/s respectively. In conclusion, samples dried with solar dryer showed a remarkable appearance, whereas, samples dried in open sun did not have appealing feature as it grew molds.
PERFORMANCE EVALUATION OF A MULTI-LAYER SOLAR TENT DRYER USING SHEA NUT
Solar dryers are developed to improve food safety and efficiency of solar drying at minimal cost. The application of any new design of solar dryer to crop drying requires adequate performance evaluation to guarantee food hygiene and cost effectiveness of the application. A newly developed multi-layer solar tent dryer by Nigerian Stored Products Research Institute was evaluated using shea nut. The evaluation was aimed at bringing out the effect of different layers on quality of shea nut and kernel as well as drying parameters. The parameters considered for the evaluation were; drying rate, cracking efficiency, percentage kernel breakage, moisture content, proximate compositions, microbial loads and sensory assessment. The obtained data were subjected to statistical analysis using SPSS 20.0 version. New Duncan’s Multiple Range Test was adopted to separate the means (P < 0.05). The results showed that the drying operation took 19 days to reduce the moisture content of boiled nut dried in the solar tent dryer from 72.1 ± 0.2 %db to 12.90 ± 1.60, 15.26 ± 2.36 and 15.76 ± 1.12 %db on layer 1 (top trays), layer 2 (middle trays) and layer 3 (bottom trays) respectively, while the control sample (sun drying) was reduced to 13.80 ± 1.50 %db. The average temperature recorded on layers 1, 2 and 3 were 47.0 ± 6.4, 38.4 ± 5.6 and 32.6 ± 2.6 °C respectively, while the control had 30.5 ± 2.1 °C. The highest drying rate of 0.90 kg/day was recorded for nut dried on layer 1 while layers 2 and 3, and control recorded 0.76, 0.73 and 0.74 kg/day respectively. The cracking efficiencies of nuts dried on layers 1 to 3 were 98.9, 99.0, 97.9% respectively, while control was 94.7%. Percentage kernel breakage of 5.68, 2.72, 2.28 and 1.73% were recorded in samples dried on layers 1 to 3 and control respectively. The proximate compositions of the dried shea kernel were not negatively impacted by the drying operation. The layer 3 recorded the highest microbial loads and was significantly different from others (P < 0.05). Therefore, the solar tent dryer could be used for drying of shea nut and kernel without quality loss in the product, but the loading should be limited to two layers for efficient quality maintenance.
DRYING CHARACTERISTICS OF INDIGENOUS GINGER RHIZOMES UNDER CABINET DRYER: AN EXPERIMENTAL STUDY
The seasonal production of indigenous ginger rhizomes as well as its rising consumption due to the medicinal and nutritional values as necessitated a need to study the drying characteristics of the product. Processing ginger into dried form helps to cut down on post harvest losses that generally occur during storage and increase the product shelf life. Drying of ginger can also increase supply, improve seasonal food choice, generate income and decrease excessive dependence on imported processed ginger. Both experimental and analytical studies of thin layer process of drying are essential for performance evaluation and improvement of drying systems. The experimental study objective is to evaluate the drying characteristics of two varieties of ginger rhizomes (Umudike ginger I and II - UG I and II) under blanched and unblanched and various treatment configurations (whole-peeled, whole-unpeeled, split-peeled, split-unpeeled) using cabinet dryer at temperature of 50oC. The highest drying rate for blanched samples was observed for split-peeled, followed by split-unpeeled, whole-peeled and whole-unpeeled. Even though blanching increases the drying rate, no significant difference between the blanching periods for the two varieties under study. The result suggests that the UG I and UG II ginger varieties exhibit same drying characteristics under similar drying conditions. In addition, the study further suggests that the general objective concerning experimental and analytical studies of thin-layer drying of ginger rhizomes for cabinet drying of the two ginger varieties were met.
EFFECT OF SOME MACHINE PARAMETERS ON FLOATABILITY AND WATER STABILITY OF FISH FEED PELLETS
Fish feeds are mostly pelletized to enable solidification of the feeds. High percentage of the floating and good water stability have become great issues of fish feed produced from a locally developed fish-feed pelletizer. The current study focuses on the effect of barrel length (140, 280, and 420 mm) and die sizes (4, 5, and 6 mm) on the floatability and water stability of pellets produced from a locally developed pelletizer. Data were collected and analyzed by using a 32×3 factorial experiment in design expert (10.01 version) at P≤0.5. Results show that pellet floatability at the 140 mm barrel length and die size of 4, 5, and 6 mm ranged from 98.0% to 98.5%, while the corresponding values obtained at 280 mm barrel length ranged from 98.0% to 98.3%, and at the 420 mm barrel length with the same die size, the pellet floatability ranged from 98.0% to 98.5%. Also, water stability at 140 mm barrel length and die size of 4, 5, and 6 mm ranged from 85.0% to 85.3%, while the corresponding values obtained at 280 mm barrel length ranged from 84.9% to 85.2%, and at the 420 mm barrel length with the same die size, the pellet floatability ranged from 85.0% to 85.1%. There was a significant effect of barrel length and die size on the water stability of the pellets produced at p ≤ 0.05. The developed fish-feed pelletizer gave a good pellet in terms of its floatability and water stability at the barrel length of 280mm and die size of 5mm, and can be used for local production of fish pellets.
ESTABLISHMENT OF A FUNCTIONAL RELATIONSHIP FOR ACHA HARVESTER MATERIAL CAPACITY AND ENERGY REQUIREMENT BASED ON MACHINE OPERATING PARAMETERS USING REGRESSION MODELLING APPROACH
Harvesting acha (Digitaria exillis), a nutritious staple food crop produced in many parts of West Africa, is still being carried out manually because an appropriate harvester is not yet available. Present cereal harvesters cannot be used to harvest acha because of its unique grain characteristics. Several parameters have been reported to influence the performance of grain harvesters, but the most fundamental are the operating speed (V), knife speed (S) and reel index (I). An attempt was made in developing a harvester that could be applied to acha harvesting. It would be essential to be able to predict the performance of the harvester for the purpose of planning, budgeting, and possible adaptation of its parameters to existing cereal crop harvesters to harvesting acha. In this study, a functional relationship between the fundamental operating parameters of the harvester and its material capacity (Cmat) and energy requirement (E) was derived. A study of the operation of the machine was made and 33 factorial experiment design was used to collect harvesting data. Quantities varied were Operating speed (V)(1,3,5 km/h), Knife speed (S)(300,400, and 500 rpm) and Reel index(I)(1,1.25 and 1.5). Quantities measured were amount of grain gathered and energy consumed. Regression analysis was performed on the data collected while Analysis of Variance (ANOVA) was used to determine the significance of the relationships. Results obtained showed that the relationships were quadratic polynomials with R2, R2a, SE, F-statistic and p-value of 0.94, 0.88, 2.47, 14,49 and 0.0000209 respectively for Cmat and 0.73, 0.60, 0.86, 5.93 and 0.0008454 respectively for E. The equations were therefore, considered good for predicting the performance of the harvester.
ASSEMBLY AND EVALUATION OF AN INSTRUMENTATION SYSTEM OF A CASSAVA PLANTER
Accuracy in measuring parameters is key in research and development of farm machinery. It is required in order to provide reliable data for farm machinery industries to mass produce efficient machines for agricultural production. Accurate measurement of draught is important for determining power requirement of a cassava planter and selecting appropriate tractor as well as choosing the forward speed to operate the planter. It is also necessary to know the number of stakes cassava planter plants per time. Therefore, an instrumentation system was assembled for simultaneous measurement of draught and the number of stakes planted per time. The system consists of a 5-ton load cell, a load cell amplifier, opto-coupler module, micro-controller, LCD display, SD-card shield and the connection cable. The system was installed between the tractor and the cassava planter with the aid of a bracket which serves as a linkage between the planter and the draw-bar of the tractor. An experiment was carried out on a tilled (flat) sandy clay loam soil to determine the effect of tractor forward speed on draught and number of stakes planted per time. In the experiment, five forward speeds of 1.5, 1.8, 2.1, 2.3 and 2.6 km/h were used at soil depth of 100 mm. The results showed an exponential relationship between forward speed and draught in which draught ranging between 24.91 and 744.44 N increased with an increase in forward speed. Planting rate varying between 30 and 42 stakes per minute were recorded at forward speed ranging between 1.5 and 2.6 km/h. Conclusively, the instrumentation system was tested and found suitable for the measurement and recording tasks it was developed for with good correlation between forward speed and draught as well as the number of stakes planted per time.
A REVIEW OF THE APPLICATIONS OF ARTIFICIAL INTELLIGENCE IN AGRICULTURE: PROSPECTS AND CHALLENGES IN NIGERIA
The agriculture sector faces numerous challenges including disease and pest infestation, insufficient available water, inadequate drainage, declining labour availability and knowledge gap between farmers and technology, leading to low outputs. More and more farmers are starting to adopt new techniques to boost productivity and increase revenue. This paper reviews the applications of artificial intelligence (AI) to agriculture and explores ways that the Nigerian farmers can benefit from this technology. AI-powered solutions have been applied in areas such as farm, crops and animal monitoring, diseases and pest detection, intelligent farm chemicals application, automatic weeding, aerial survey and mapping, smart irrigation, intelligent produce grading and sorting, among others. These will not only enable farmers to do more with less, but will also improve quality. Obstacles of inadequate technology infrastructure such as broadband internet access, and paucity of a workforce with the right skills exist in Nigeria, but with continuous efforts currently being made, they will be overcome. It is concluded that the application of AI holds great promise for improved productivity and better utilisation of resources.
DETERMINATION OF EFFICACY OF NSPRIDUST® AS MAIZE PROTECTANT IN SILO
The use of conventional silos for grain storage involves application of synthetic pesticides that produce harmful residue after use. This study was aimed at investigating the efficacy of NSPRIDUST® as a protectant for maize stored in silo with respect to insect control and quality maintenance. Maize treated with NSPRIDUST® in ratio 1:1000 (NSPRIDUST®: Maize) by mass was stored in 2 experimental silos of 500 kg loaded to 80% of its capacity. The NSPRIDUST® was applied to the maize using NSPRIDUST® applicator. Another set of 2 experimental silos were loaded with untreated maize to capacity to create hermetic condition (control). Five hundred (500) newly emerged unsexed adults of Sitophilus zeamais (primary insect pest of stored maize) were introduced into each silo in batches of one hundred (100) insects to ensure proper distribution of the as the grains were loaded. The maize was stored for 12 months and samples were drawn from the silos monthly to determine insect count, germinability and moisture content, while microbial loads and proximate composition were determined before and after the storage using standard laboratory methods. The result shows that the NSPRIDUST® treated maize had no live insect and suppressed F1 generation throughout the storage period depicting a 100% insect mortality, while insect mortality in the control were 75, 83.33 and 100% for the first, second and subsequent sampling months respectively. The effects of NSPRIDUST® on the live insect count, F1 emergence and moisture content of maize grains were statistically significant (p < 0.05). NSPRIDUST® caused reduction in bacteria load and fungal count by 80 and 73% respectively, and both were within the acceptable limit (<0.3 x 103 cfu/g). It is an effective protectant for maize in silo storage as it maintained grain quality and suppressed proliferation of microbial loads during the storage. Therefore, the application of NSPRIDUST® as a grain protectant could be extended to silo storage of grain.
ASSESSMENT OF THE ADSORBENT CAPACITY OF SAWDUST BRIQUETTE IN TREATING CRUDE OIL CONTAMINATED WATER
In crude oil catchment areas of oil-producing countries, oil spillage is a serious environmental challenge. As a result, fertile agricultural lands get polluted and degraded, the morbidity of aquatic animals is rampant, and water is rendered unfit for drinking and general household usage. This work offers a solution to this environmental menace by utilizing sawdust briquettes as filter media in filter columns to purify crude oil-contaminated water. Subjecting both the oil-polluted water and treated water to total petroleum hydrocarbon (TPH) test and water quality test, the study investigated the effectiveness of using the filter columns and the suitability of using the treated water for irrigation purposes. From the results, the adsorption capacity was in the range of 2.86 and 4.01 g/g. It was established that the filter was very effective in treating oil-polluted water as the TPH concentration sharply reduced to about 96.1% from 32960 mg/L in the oil-polluted water to 1284 mg/L in the treated water. However, the reduced TPH, was above the EU EPA standard TPH level required for river and basin waters. The physicochemical properties for the treated water as compared with the oil-polluted water showed drastic ECw increase (172.13 ± 0.06 to 708.00 ± 114.59 μS/cm, depicting slight salinity), increased TDS (114.24 ± 0.01 to 479.33 ± 44.99 mg/L), reduced pH but very strongly acidic (6.50 ± 0.00 to 4.37 ± 0.06), reduced turbidity (8.96 ± 0.02 to 5.88 ± 0.24 NTU), increased alkalinity but below optimum (13.12 ± 0.01 to 21.59 ± 0.76 mg/L), and reduced colour (55.18 ± 0.03 to 15.10 ± 0.56 Hz). For the heavy metals, only Copper (Cu), Chromium (Cr) and Iron (Fe) were within the standard limit of irrigation waters while Cadmium (Cd) and Manganese (Mn) were not. It was, therefore, concluded that though it is evident that the use of sawdust briquette as a filter is effective at reducing TPH in crude oil-contaminated water, the treated water is altogether not suitable for irrigation purposes. Therefore, it was recommended that the sawdust filter be upgraded to attain TPH level standard limit.
TECHNOLOGICAL CAPABILITY OF SMALL-SCALE OIL PALM FRUIT PROCESSORS IN THE PRODUCTION OF SPECIAL PALM OIL IN NIGERIA
This study assessed the technological capabilities of oil palm fruit processors in Akwa Ibom, Edo, Imo, Kogi, Ondo, and Osun States, Nigeria. This is with the view to ascertaining the availability of appropriate technologies for production of special palm oil (SPO). Relevant data were collected from 307 respondents, who were selected by multistage sampling procedure. Appropriate descriptive statistics (frequency of observations, percentages and statistical significance) were used to summarise the data and deduce inferences. Many of the respondents were between 50 and 59 years age group (27.0%) and between 40 and 49 years of age (25.4%), which indicates that a significant number of the processors were adults. Majority (87.4%) of the mills were owned by single private actors. Many of the respondents (63.93%) did not know about SPO production. The most and least available equipment were vertical digester and centrifuge which were found amongst 62.5 and 0.98% of the processors, respectively. Availability of stripper (p < 0.05), sterilizer (p < 0.05), digester-screw press (p < 0.05), centrifuge (p < 0.05), and decanter (p < 0.05) were associated with highest educational attainment of processors. The paper concluded that technological capability of SPO processors was very low; hence the need for interventions that would increase respondents’ awareness about appropriate technologies for SPO production. This promises great boost in obtainable income and job generation for key actors in the oil palm value chain.
IMPACT OF MAGNETIZED WATER ON COMPRESSIVE STRENGTH AND DURABILITY OF SANDCRETE BLOCK
Cases of collapse of buildings is common in Nigeria due to failure of materials used for the construction and poor design. Sandcrete block is commonly used for the construction of buildings in the country but the sandcrete blocks are normally fragile which demands ways to improve the strength of the sandcrete block. Magnetized water is water that has passed through a magnetic field which enhances proper hydration when it is used for producing sandcrete block and it has the ability to improve the strength of the block. The magnetic water treatment unit was fabricated using a broken permanent magnet from speaker with magnetic flux of 997 Gauss and neodymium magnet rated 1.3 T (1.3 x 104 G), a hose of 25.4 mm diameter, 25.4 mm diameter pipe, 50 litres storage bucket and water control tap. The magnetic treatment unit is 900 mm long with 450 mm hose surrounded by a broken magnet from speaker and a 450 mm long pipe surrounded by 12 pieces ofneodymium magnet. The magnetized water was treated for 11 s (T1), 33 s (T2) and 55 s (T3) but the control was non-magnetized water (T0). Dangote Portland cement and sand sieved through 4.75 mm were mixed (batching) and the ratio of cement to sand was 1 : 6 by weight and optimum moisture content used for producing the block was 9%. The solid sandcrete block (230 x 100 x 100 mm) was produced using a manually operated moulding block machine. The blocks with 3 replicate for each treatment were cured for 7, 14 and 28 days. After curing for 28 days, the force at peak, compressive strength were determined using Universal Testing Machine of capacity 300 kN (model FT300CT by Testometric Company Limited, United Kingdom). After curing for 28 days, the compressive strength for T0, T1, T2 and T3 were 2.358, 4.742, 3.406 and 4.903 N/mm2, respectively. The compressive strength for T1, T2 and T3 increased by 7.97 - 18.24, 17 - 39.51 and 44.44 - 107.93% after curing for 7, 14 and 28 days, respectively when compared to T0. Young’s modulus for T1, T2 and T3 increased by 41.74 – 74.48, 14.33 – 39.01 and 43.28 – 79.02% after curing for 7, 14 and 28 days, respectively. The magnetized water increased the compressive strength of the sandcrete block and is recommended for producing sandcrete blocks in the country.
INFLUENCE OF TILLAGE, NUTRIENT AND WEED MANAGEMENT ON CHEMICAL PROPERTIES OF SANDY-LOAM SOIL AND YIELD OF SOYBEAN
Adoption of crop management practices that are directed at achieving a self-sustaining system for soil protection is critical to sustainable crop productions. The influence of four tillage depths (T1 = Disc plough and disc harrow at 25 cm depth, T2 = Disc plough at 20 cm depth, T3 = Double tillage pass of disc harrow (DDH) at 15 cm depth, T4 =Single pass of disc harrow at 10 cm depth),three nutrient applications (N1 = No nutrient application (Control),N2= Farm Yard Manure (FYM) at 0.5 ton/hectare (applied during tillage operation) + 50 kg/hectare of Superphosphate applied 4 weeks after sowing, N3 = FYM at 1 ton/hectare (applied during tillage operation) + 75 kg/hectare of Superphosphate applied 4 Weeks After Planting) and four levels of weed management (W1 = No weeding as control, W2 = 3 litres of pre-emergence at planting + Post-emergence (Fusillade forte) at 2.5 litres (0.14 kg/ha) of post emergence at 3WAP,W3 = 3 litres of pre-emergence + 3 litres (0.17kg/ha) of post emergence at 5WAP,W4= 3 litres of pre-emergence + 4 litres (0.23 kg/ha)of post emergence at 7WAP were used for the production soybean in 2018 and 2019 planting seasons. The results showed that tillage systems between 10-15 cm depth of cut favour availability and retention of soil nutrients within the tap root of soybean as in the case of T3 (DDH at 15 cm) that recorded the highest mean values of Soil Organic Matter (SOM) (1.77), Soil Organic Carbon (SOC) (1.40), total N (0.41%), available P of 4.82 ppm and exchangeable K of 0.22 C mol/Kg. In terms of nutrient application, N3 had the highest SOM (1.90), Mg2+ (1.99), Ca2+ (1.28), Total N (0.41), available P (4.48) and exchangeable K (1.32) during harvesting time. T3 (DDH at 15 cm) had the highest mean values of pod/plant (74.78), 1000 seed weight (134.83g) and highest mean value of grain yield of 2.43 tons/ha, however, it was not significantly different from yield 0f 2.35 tons/ha obtained in T1 (Disc plough and disc harrow at 25 cm depth).Weed management practices did not significantly influence soil chemical properties soil pH, soil organic matter, soil organic carbon, Magnesium, Nitrogen and others chemical properties analysed for the soil were uniformly distributed among the treatment at p≤0.05. It is important that soybean farmers adopt management practices that are directed at achieving a self-sustaining system of the soil. Hence, tillage depth at 15 cm and minimum application of compost poultry manure are recommended for a sustainable soybean production.
DETERMINATION OF CROP AND MACHINE PARAMETERS RELEVANT TO THE HARVESTING AND POSTHARVEST HANDLING OF ACHA
Acha (Digitaria species) is a cereal crop produced predominantly in Nigeria. Harvesting acha is still being done by traditional methods. Existing regular combines cannot be applied to acha harvesting due to its unique grain characteristics. Appropriate harvesters suited to the characteristics of acha seed are not available. The aim of this study was to determine some crop and machine Parameters (CMPs) relevant to acha harvesting. Machine parameters were determined from the known empirical equations for effective material capacity while standard laboratory investigations were conducted to determine crop parameter (Angle of Repose, Particle Density, Particle Size, Coefficient of Uniformity and Fineness Modulus). Results obtained showed that operating speed (V) (1, 3, 5 km/h), knife speed (S) (300, 400, 500 rpm) and reel index (I) (1.0, 1.25, 1.5) were critical parameters in the design of an acha harvester. Angle of repose, particle density, particle size, coefficient of uniformity and fineness modulus of acha were found to be 32.5°, 0.584 g/cm3, 0.60 mm, 1.62 and 1.22 respectively. Not considering these parameters in the design of acha harvesting and handling machines results in heavy grain losses. It is therefore recommended that information from this work be adopted in the design of acha handling machines.
COPPER REMOVAL USING OCHROBACTRUM SPECIE ISOLATED FROM CONTAMINATED WASTEWATER
Bacterial and metal removal have received considerable attention recently, due to the potential use of microorganisms for treatment of contaminated wastewater. Removal and recovery of heavy metal ions from polluted wastewaters has appeared to be the potential alternative method for conventional treatment of contaminated wastewater. The purpose of the present work was to study the removal capacity of toxic metal from contaminated wastewater by using ochrobactrum sp. isolated from contaminated wastewater using different pH and temperature. Bacteria species have a high surface area to volume ratio, due to their small size and thus, they can offer a large contact interface that would interact with metals ion. The results indicated that bacterial isolate Ochrobactrum sp. is a suitable biosorbent for the removal of Cu (II) ion from metal polluted wastewater and might be applicable to the development of possibly cheap biosorbent for removing and recovering copper from effluents.
PHYSICOCHEMICAL PROPERTIES OF BIODIESEL BLENDS DERIVED FROM MAHOGANY (KHAYA SENEGALENSIS) SEED OIL FOR USE AS ALTERNATIVE FUEL
Plants from different regions produce oils with characteristics that vary by wide margins and depend more on the regions in which the plants are grown than the species from which the oils are derived, most probably as a result of the environmental conditions to which they are exposed. This study aims at producing biodiesel by transesterification of Khaya Senegalensis seed oil (KSO) and the determination of physicochemical properties of the biodiesel blends, compared with ASTM D6751 and EN14214 standards. Properties analyzed include: density, viscosity at 250C, iodine value, saponification value, cloud point, pour point, flash point, acid value, free fatty acid, higher heating value and sulphur content. The transesterification reactions were maintained at the optimum process conditions of methanol/oil ratio 6:1, at 70˚C for 60 minutes at 0.84% (w/v) of catalyst concentration. A biodiesel yield of 89.50% was obtained. The results for density (844 – 837 kg/m3), kinematic viscosity (4.44 – 4.07 mm2/s), iodine value (92 - 127 mgI2/100g), saponification value (11.22 – 36.47 Mg/KOHg), cloud points (9 - 14 ᶱC), pour points (11 - 19 oC), flash points (110 - 190 oC), acid value (0.21 – 0.78 Mg/KOHg) and the sulphur contents (2.15 – 2.86 mg/kg) of the biodiesel blends (B10, B20, B30, B40, B50 and B100) conformed with both the ASTM D6751and EN14214 standard, with higher heating value of the blends slightly above both standards. It was concluded that with the high yield and quality properties of the biodiesel blends, the potential of using KSO biodiesel blends as an alternative fuel on a diesel engine.
INVESTIGATING THE EFFECT OF BLADE CUTTING ANGLES OF A MANUAL HOE ON OPERATOR’S HEART RATE DURING WEEDING OPERATIONS
The present findings focus on the assessment of manual hoe blade cutting angles on operator heart rate during weeding operation. Three hoe blades were developed with different blade cutting blade angles (65o, 75o, and 85o) using AutoCAD software and analyzed by 3D modeling. Heart rate (bpm) was measured using a polar heart rate monitor and recorded at rest, during the entire period of work and recovery thereafter for a period of 5 mins. Soil bulk density and moisture content (db) were determined using a standard method from literature. Randomized Complete Block Design (RCBD) was employed to evaluate the effect of hoe blade cutting angle, soil moisture content, soil bulk density and the operator’s height on the heart rate of the operator during weeding operations. Three levels of cutting angles (65o, 75o and 85o), bulk density (1.2, 1.3 and 1.5 g/cm3), moisture content (13, 15 and 18 %) and two different operator’s heights (1.56 and 1.65 m) making a 3 x 3 x 3 x 2 factorial experiment design and analyzed using ANOVA and Tukey’s Studentized Test mean comparison. Results obtained show that mean heart rate increases with an increase in soil moisture content, soil bulk density and operator’s height respectively, but decreases with hoe blade cutting angle. The optimum heart rate of 84.24, 80.35, 72.01 and 74.61 bpm were obtained at 85o blade cutting angle, 15% soil moisture, 1.2 kg/m3 bulk density and 1.56m operator’s height respectively. It was, however, recommended that a study on manual hoe be carried out to ascertain its effects on the weeding index, performance index and cost of operation.
DETERMINATION OF SOME PHYSICAL PROPERTIES OF CANARIUM SCHWEINFURTHII ENGL NUTS FROM NIGERIA
Physical properties of three varieties of Canarium schweinfurthii nuts (Canarium schweinfurthii short (CSHTS), Canarium schweinfurthii long (CSHTL) and Canarium schweinfurthii large (CSHTLRG)) were studied at three different moisture contents (10.20%, 17.23% and 25.06%) wet basis. The values of physical parameters studied were obtained experimentally and analyzed using ANOVA at 5% alpha level. The results showed that the principal dimensions of large nuts ranged from 32.29 - 32.91 mm (major diameter), 16.07 - 16.55 mm (intermediate diameter) and 15.69 - 16.26 mm (minor diameter). The values of sphericity, mass and density of large nuts also ranged from 0.62 – 0.63, 4.32 - 4.90 g and 1.27–1.21 g/cm3 respectively. The long nuts had 36.75 - 37.36 mm (major diameter), 13.67 - 13.19 mm (intermediate diameter) and 13.18 - 12.89 mm (minor diameter). The sphericity ranged from 0.50 – 0.51, mass from 2.79 - 3.14 g and density from 1.14 – 1.07 gcm-3. The major diameter of the short nuts ranged from 23.26 - 23.87 mm, intermediate diameter from 10.93 - 11.24 mm and minor diameter from 10.76 - 11.04 mm. The values of sphericity ranged from 0.60 – 0.62, mass from 1.21 - 1.43 g and density from 1.14 – 1.06 gcm-3. The nuts are oblong shaped with surface areas of 336.7 mm2, 301.55 mm2 and 164.28 mm2 for large, long and short varieties respectively. Moisture content had no effect on the geometric dimensions but significantly (5%) affected mass, density and surfaces area. The porosity of all the nut varieties studied decreased as moisture level increased and the density values were higher than one, hence cannot be separated by floating. Rubber surface had the highest coefficient of friction than the other material surfaces studied. All physical parameters investigated had good relationship (high R2 values) with moisture content. These results are essential in design and development of machines and equipment for processing and handling this product.
THIN LAYER DRYING OF SOME SELECTED VEGETABLES IN A FORCED CONVECTION SOLAR DRYER WITH ENERGY BACKUP SYSTEM FOR CONTINUOUS DRYING OPERATION
Vegetables (tomato, pepper and ginger) are high moisture agricultural products that normally begin to undergo deterioration immediately after harvest. Heavy losses of the products usually occur as a result. Farmers employ open air sun drying to control the losses and this has the disadvantages of exposing the products to rain and dust contamination, insect and rodent attack and poor quality outputs. Most of the solar dryers already developed have the inability to continue the drying process during off sunshine hours of the day. If drying process has not come to completion prior to sunset, the operation has to be broken to commence again when the sun rises the next day. During the break in drying, normally at night, certain biochemical reactions can occur and lead to the commencement of material deterioration. The novel continuous drying solar dryer was developed to address the above problem, and it was used to determine the drying characteristics of tomato, pepper and ginger in the temperature and relative humidity ranges of 17 - 60 oC and 10 - 76%, respectively. Each product was dried in thin layer and moisture loss was monitored with time. Fourteen popular thin layer-drying models were tested using the data obtained. Results showed that tomato, pepper and ginger dried from 95 to 6.3%, 88 to 18.2% and 84 to 19.8% moisture contents in 15, 16 and 12 hours, respectively. The products dried mainly in falling rate phase. The values of effective diffusivity for tomato, pepper and ginger in the dryer were 2.1885×10-9 , 2.3101×10-9 and 2.4317×10-9m2/s respectively. Aghbashlo et al. model with randomized residual plots, lowest RMSE and highest R2 was the best model for predicting the drying behavior of tomato, pepper and ginger in the dryer.
PERFORMANCE EVALUATION OF GYPSUM BLOCK, TENSIOMETER AND MOISTURE SENSOR FOR SOIL MOISTURE CONTENT DETERMINATION
Measurement of soil moisture has become very critical in irrigation water management studies especially in Africa. This research investigated the response of Tensiometer, Gypsum blocks and Sensor to changes in soil moisture and their appropriateness for irrigation scheduling on farms. Gypsum block was fabricated using a mould containing 15 cubicles of size (5x 4 x 2.5) cm in a wooden box frame, tensiometer irrometer – model SR was used to measure soil moisture tension. Arduino 1.8.7 board connected to two probes was used to build the soil moisture sensor. The three soil measuring devices were installed, calibrated and validated using the gravimetric method as the standard. The response of each moisture testing device was carried out using a t-test at a 5% significance level. The results revealed that the value of bulk density, field capacity, PH and electrical conductivity of the soil obtained were 1.463g/cm3, 20%, 5.50 and 0.034dS/m, respectively. The soil was sandy loam with percentage contents with sand, silt and clay in the soil were 69.8%, 19.4% and 10.8%, respectively. The mean difference between the Gravimetric method, compared to gypsum, Tensiometer and Sensor, was 6.30, 3.95 and 3.02, respectively. It could be concluded that the Sensor used with the Adruino board measures moisture content more accurately than Gypsum and Tensiometer.
WATER MANAGEMENT OF TOMATO CROP ROOT ZONE USING AQUACROP
Water content at the root zone remains the major source of water to the plants which can be determined using various methods such as oven-dry or gravimetric; neutron moisture meter (NMM); electromagnetic sensors(capacitance sensors); conventional time domain reflectometry; tensiometers and other several new technologies which include FAO aquacrop. The objective of this paper is to study the response of crop growth to water contents at root zone and soil profile with a view to eliminating crop failure due to water stress. The research location was at Epe in Lagos state, Nigeria, and climatic data required include rainfall (mm), radiation (MJ/M2), maximum and minimum temperature (oC), wind speed (m/sec), mean relative humidity (%) and Carbon Oxide concentration from 1982 to 2018 daily obtained from the archive of National Aeronautics and Space Administration. Aquacrop used was of version 6.1 FAO and crop chosen was tomato and simulation was run from 9th November 2017 to 26th February 2018 under drip irrigation. The results show that maximum water contents in entire soil profile, effective root zone, saturation, field capacity, leaf expansion, stomatal closure, canopy senescence, and permanent wilting point of loamy sand were 330.3, 300.0, 500, 300, 264.8, 195.9, 156.8 and 100 mm respectively. Achieving effective irrigation water management entails a cursory look at water contents in effective root zone since it is only major source of water to plants. Hence, the study contributes among others to the body of knowledge by aiding better understanding of plant- soil- water relationship and providing mitigation information against climate induced drought.
PYROLYSIS CHARACTERISTICS AND KINETICS OF OIL PALM BIOMASS: A PATHWAY TO PRODUCING ENGINEERED BIOCHAR
Biochar produced from oil palm biomass has been demonstrated to be effectively utilized in energy, soil amendment, wastewater treatment, catalyst and composting applications. However, the industrial development of biochar plants for specific biomass requires an adequate description of the pyrolysis process of the feedstock. Knowledge of biomass devolatilization characteristics and kinetics may describe the pyrolysis process adequately, which would be needed for the proper industrial process design and optimization. Therefore, in this review, the thermal degradation characteristics and pyrolysis kinetics of oil palm biomass residues are discussed to reveal important influential factors and pyrolysis reaction mechanisms. The findings from the literature indicate that the main devolatilization temperature range and the overall reactivity are 352 to 380 °C and 0.360 mg min-1 °C-1 for kernel shell, 336 to 360 °C and 0.270 mg min-1 °C-1 for mesocarp fiber, and 329 to 356 °C and 0.530 mg min-1 °C-1 for empty fruit bunch. The kinetic parameters for the consecutive reactions model suggest that the ease to commence pyrolysis reaction was in the following order: frond < kernel shell < mesocarp fiber < empty fruit bunch. The percentage biochar yield for the residues was higher than 23 wt.% under slow pyrolysis conditions and the tendency of obtaining high biochar yield followed this order: kernel shell > mesocarp fiber > empty fruit bunch > trunk > frond. The tendency for high biochar yield could be attributed to the proportion of lignin content which slowly decomposes over a wide temperature range. The treatment temperatures of 400, 500, and 600 °C are adequate to carbonize the oil palm biomass residues for producing biochars suitable for use as biofuels, activated carbon, and reducing agent, respectively.
QUANTITY, QUALITY AND STORAGE OF HARVESTED RAINWATER FOR POULTRY PRODUCTION IN NORTHERN AKWA IBOM STATE, NIGERIA
Adequate water supply is a growing constraint for poultry producers because they are not served by government piped water network and individuals must make alternative arrangements for their water needs. Adequate water supply is a growing constraint for poultry producers. Roof-harvested rainwater of adequate quantity and acceptable quality provides alternative supply of water but needs storage during non- rain periods. This study investigates the adequacy of harvested rainwater, quantity and storage requirements as well as quality assessment for small and medium scale layer chicken production in Akwa Ibom State. The research design for the study is basically survey design and experimental design. The instruments used for investigation are questionnaire survey, face to face interview and observation. Experimentation was done in the laboratory to investigate physical, chemical and microbiological samples of rain water from the households in Akinima community. Monthly rainfall, water use, housing characteristics and average roof catchment areas data were input to the mass curve principle and used to predict the maximum storage for the production scales. The dimensionless graph principle was then employed to scale down the maximum storage to the required storage. Average demand in all the LGAs in the study was less than 50% and 42% of supply for 500 and 1000 chicken population respectively. Water quality index assessment of the rainwater based on WHO standards showed excellent quality ranging between 0.876 – 38.453 in all the LGA’s. These findings establish that rainwater can be harnessed for poultry production in the study area. The study can be extrapolated to other areas.
EVALUATION AND MODELING OF ENERGY INPUT AND FIELD EFFICIENCY OF PLOUGH ON LOAMY SAND SOIL IN ABIA STATE, NIGERIA
A research was conducted to evaluate and model the energy intake rate and field efficiency of plough on loamy sand soil in Abia State, Nigeria to assist farmers in the area scrutinize and select appropriate ploughing implement for efficacious and increased production. The tractor model of MF430E and capacity of 55.2 kw made by Massey Ferguson Company and a disc plough with operating units of 3 bottom discs was used for the study. The operational speed and depth of cut were adopted as factors for the study of the energy intake and field efficiency of the plough. Results revealed that the highest fuel intake of 31.25 lha-1 was recorded when the plough was operated at the depth of 30 cm for the different speeds and that the highest field efficiency of 80.0% was recorded at the cutting depth of 30 cm and speed of 5 kmh-1 while the least efficiency of 68.1% was achieved at speed of 9 kmh-1 and depth of 10cm. A quadratic model was statistically significant (P ˂ 0.05) for the prediction of field efficiency with coefficient of determination, R2 of 0.9767 while a linear model was significant (P < 0.05) for the evaluation of energy requirements of the disc plough with coefficient of determination, R2 of 0.6500, which indicated good correlations between the variables. The optimum field efficiency and the desirability of 77.50% and 1.00 were respectively achieved at optimum speed of 7 kmh-1 and ploughing depth of 30 cm. While the optimum fuel consumption rate and the desirability of 20.51 lha-1 and 1.00 were respectively gotten at optimal operational speed of 6.7 kmh-1 and ploughing depth of 18.56cm. Finally, results of simulation revealed that the fuel consumption rate and field efficiency obtained from the generated models fall within the experimental range. Farmers can therefore, evaluate and chose the implements using the developed model as a guide.
DETERMINATIONS OF SOME TYPHA MINERAL COMPOSITION AND ORGANIC LOADING RATE FOR ANAEROBIC DIGESTIONS
Choice of good substrate and organic loading rate in anaerobic digestion of biomass for biogas generation was among the critical factors needed to achieve a stable biogas system. This study determined some nutrient compositions require by anaerobic microorganism for biogas production from typha biomass and evaluate biogas production at different organic loading rates under laboratory condition. The nutrients compositions from typha plants were determined from standard laboratory procedures while the organic loading rate a single factor experiment was design in completely randomized design (CRD) at four level of organic loading rate: 0.2, 0.4, 0.6, and 0.8 g/100 ml and hydraulic retention time of 34 days. The experiments were repeated three times for four weeks. The results were analysed using statistical analysis Software (SAS). The digesters were feed after 4 - 5 days intervals and the system operated at mesophilic temperature (38 – 39 oC). The system has a total volume of 125 ml with a working volume of 105ml. Volume of biogas produced from each unit of the digester was measured using a glass syringe while the methane was measured with the used of sodium hydroxide solution. The study established that the plant has a nitrogen content of 0.34 - 1.58%, while organic carbon had 52.42 - 55.78%. Calcium concentration found to be 0.69 -1.36 % and phosphorous, magnesium, potassium, and sodium obtained to be: 0.03 - 0.29, 0.07 - 0.23, 0.73 - 3.13 and 0.13 - 1.21%, respectively. Similarly, iron was within the range of 196 - 707 ppm while manganese 261 - 752 ppm. The zinc range was 7 - 26 ppm while copper 2 - 9 ppm. Neutral detergent fiber (NDF) varies from 59 - 75%. Acid detergent fiber (ADF) ranged 34 - 60%, while lignin concentrations range 12 - 21%. High carbon to nitrogen ratio obtained with the range from 34 – 162/1. Ash content was 5.05 - 10.74%. For the gas generation, 0.6 g produced the highest cumulative volume of gas while 0.4 g with the highest methane yields. However, 0.2 g has the highest efficacy with the gas yield of 366 ml/ g volatile solid (VS). It is advantageous to operate with 0.2g due to higher volatile solid.
DESIGN, CONSTRUCTION AND PERFORMANCE EVALUATION OF A PORTABLE SWEET POTATO SLICER
This study focused on the design, construction and performance evaluation of a portable motorized sweet potato slicer. The components of the slicer include a feeding trough, frame, slicing disc, collection tray and power transmission unit. The machine was powered by a 1 hp electric motor. A 3 x 2 factorial experiment in a Randomized Complete Block Design (RCBD) was used to investigate the effects of operational speeds (312, 406 and 501 rpm) and tuber diameters (25-50 and 51-70 mm) on the performance of the machine in terms of slicing efficiency and machine capacity. The performance evaluation of the slicer was carried out in triplicates and ANOVA was used in evaluating the results. The results from the study showed that variations in operational speed had significant effect (p≤0.05) on slicing efficiency and machine capacity while effect of tuber size was only significant (p ≤ 0.05) on capacity and not significant on the slicing efficiency. The slicing efficiency of the slicer increased from 74.4% to 94.1% and 76.0% to 96.4% for 25-50 mm and 51-70 mm tuber diameters respectively as the operational speed decreased from 501 to 312 rpm. The optimum rotational speed of the slicer obtained was 312 rpm at an average efficiency of 94.5% and capacity of 128.46 kg/h. The thickness of the slices produced from the slicer ranged from 2-4 mm. The machine helped to reduce drudgery associated with manual slicing of sweet potato.