UNIZIK Journal of Agricultural and Biosystems Engineering
The UNIZIK Journal of Agricultural and Biosystems Engineering (UJABE) is an online, open-access, peer-reviewed and indexed journal publication of the Department of Agricultural and Bioresources Engineering (ABE), Nnamdi Azikiwe University, Awka, Anambra State, Nigeria. UJABE provides a platform for the publication of high-quality original research/technical papers across all areas of agricultural and biosystems engineering and related subjects. It is published in 6 issues annually. 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, emerging technologies, 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.
UNIZIK JOURNAL OF AGRICULTURAL AND BIOSYSTEMS ENGINEERING
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THE CHARACTERIZATION OF WATER LILY BRIQUETTES WITH BANANA PEEL BINDER
The study assessed the interaction of binder proportion with burning characteristics of banana peel blended water Lily fuel briquettes. For this study, a constant mass (30g) of water lily powder was used across all mixtures, while a varying mass of banana peel, i.e. (0%, 20%, 40%, 60%, and 80% of the 30g mass of water lily was correspondingly used for the respective mixtures). The resultant homogenous feedstock, hydrated with 200ml of hot water, was compacted in a steel cylindrical die with 14.21 cm as height and 2.14 cm as diameter, applying pressure of5 MPa, and observing a hold time of 20 minutes. The briquettes were then expelled for additional research. Fixed carbon ranged from 16.68 % to 25.38 %, volatile matter from 50.5 % to 56.8%, Ash from 15.4 % to 18.2% and calorific value from 24751kJ/kg to 25737 kJ/kg. These calorific value range recommend this briquette variants, suitable for small scale heating application, in line with solid fuel standard (DIN 51731:1996-10), which stipulate among other requirements, 17000 kJ/kg as the threshold minimum calorific value for solid fuels. Based on the experimental results, it was observed that the binder increment in the feedstock composition, lengthened the briquettes' igniting period, but decreased their burning rate.
DEVELOPMENT AND PERFORMANCE EVALUATION OF A MOTORIZED TWO-ROW IRISH POTATO PLANTER FOR IMPROVED PRODUCTIVITY IN SMALLHOLDER FARMING SYSTEMS
Irish potato (Solanum Tuberosum L.) is a globally important food and cash crop that contributes significantly to food security, income generation, and nutrition, particularly in developing economies. Despite its importance, Irish potato production in many regions remains constrained by labor-intensive traditional planting methods that result in poor seed placement, inconsistent planting depth, and reduced field efficiency. Agricultural mechanization of planting operations offers a viable pathway for improving productivity, uniformity, and timeliness of operations, especially for smallholder farmers. This study presents the design, development, and performance evaluation of a motorized Irish potato planter suitable for small- to medium-scale farming systems. The planter was developed using locally available materials and evaluated under field conditions such as tractor-tilled sandy-loam soil, flat topography, and different operating speeds of 1.8 kmh-1, 2.5 kmh-1, 3.0 kmh-1 for seed spacing accuracy, planting depth uniformity, field capacity, field efficiency, and seed damage. Performance results demonstrate significant improvements in planting uniformity of 307 ± 20 mm and operational efficiency of 83 % when compared with manual planting practices. The study demonstrated that the developed Irish potato planter performed satisfactorily under field conditions, achieving optimum performance at an operational speed of 2.5 km h⁻¹ with a metering efficiency of 95%. The findings further indicate that the adoption of the planter has significant potential to improve Irish potato production while providing a technically feasible and economically affordable planting option for smallholder farmers.
EFFECT OF ASHOKA (SARACA ASOCA) LEAVES BIOFERTILIZER ON THE PHYSICAL AND CHEMICAL PROPERTIES OF IRRIGATED SOIL
Managing soil sustainably in irrigated agriculture continues to be a significant difficulty because of soil deterioration, nutrient disproportions, and salinity resulting from overuse of synthetic fertilizers. This research assesses how Ashoka (Saraca asoca) leaf biofertilizer influences the physical and chemical characteristics of irrigated soils. A regulated greenhouse trial was performed employing a completely randomized design (CRD) and various dosing levels of Ashoka leaf powder. Soil specimens were examined prior to, throughout, and following the treatment. ANOVA-based statistical evaluation uncovered notable (p < 0.05) enhancements in soil attributes. The average organic carbon content was 2.19%, and available phosphorus rose markedly from 76.20 ppm to 257.78 ppm. Regression analysis demonstrated a robust positive correlation (R² = 0.96) between biofertilizer usage and soil fertility metrics. The findings verify that Ashoka leaf biofertilizer serves as an efficient, sustainable substitute for inorganic fertilizers in irrigated agriculture.
BIOREMEDIATION POTENTIAL OF ORGANIC POLLUTANTS IN A CRUDE OIL CONTAMINATED LOAMY SOIL IN NIGER DELTA REGION
This study investigated the instigation of organic pollutants in crude oil-contaminated loamy soils in Nigeria. The findings demonstrated that contamination alters soil physico-chemical properties, increases levels of toxic hydrocarbons, and reduces microbial diversity. While hydrocarbon-degrading microbes adapt and proliferate, the persistence of pollutants like PAHs and asphaltenes indicates a long-term ecological challenge. The results emphasize the urgent need for remediation measures and stricter environmental management in oil-producing regions.
HYDROLOGICAL MODELLING AND IDENTIFICATION OF EROSION-PRONE ZONES IN THE UPSTREAM CATCHMENT OF EDE DAM, NIGERIA USING SWAT
This study evaluates hydrological processes and identifies erosion-prone zones in the upstream catchment of Ede Dam, Osun State, Nigeria, using the Soil and Water Assessment Tool (SWAT). Spatial datasets, including Digital Elevation Model (DEM), land use, and soil maps, were integrated with long-term climatic data (1991–2021) obtained from the Nigerian Meteorological Agency. The watershed was delineated into 21 sub-basins and 36 Hydrologic Response Units (HRUs). Model calibration and validation showed satisfactory performance with coefficient of determination (R²) values of 0.70 for sediment yield and surface runoff, and 0.65 for streamflow. Peak streamflow (191.26 m³/s) and sediment yield (21.46 t/ha) were recorded in 2003 and 2006, respectively, while minimum values occurred in 2008. Sub-basins 3, 5, 11, 13, 14, and 15 were identified as erosion hotspots. The study demonstrates the effectiveness of SWAT integrated with geospatial data for hydrological modelling and sustainable watershed management.
POSTHARVEST FARM PRODUCE HANDLING IN NIGERIA AND ITS IMPLICATION
Poor handling of agricultural products in Nigeria leads to post-harvest losses that hamper food security, farmers' livelihoods and economic growth and development. This study evaluates the trends associated with post-harvest losses in crops (maize, cowpea, cassava and tomato) and livestock products (cattle, milk, layers and broilers) in Nigeria from 2022 to 2024. The information was collected from the National Agricultural Extension and Research Liaison Services (NAERLS) reports of the Annual Agricultural Performance Survey (APS). The data collected were subjected to chi-square and ANOVA analysis. The results obtained revealed that post-harvest losses are quite high varying from 15% to over 40%. Poor road networks, poor electricity supply, inadequate storage facilities, and security concerns are some of the leading factors responsible for the losses. Some improvements were recorded for cassava, cowpea, and tomato crops, especially with the decline in cassava losses at an estimated average rate of 5.5% per year. The economic evaluation indicated that these losses had a significant impact, as farmers earned more income of up to ₦105,000 per hectare in tomatoes and ₦85,800 in cassava each year. However, consistent insecurity, low adoption of modern technologies, high price of inputs and processing equipment hinders this impact. This study recommends that specific measures be taken to address the menace faced by each commodity (storage facilities and processing equipment). There is also the need for improving the rural infrastructure and establishing a system to record and monitor for post harvest loss in Nigeria.
WATER QUALITY MODELING USING ARTIFICIAL NEURAL NETWORK AT THE DEAD-END SECTIONS OF DRINKING WATER DISTRIBUTION SYSTEM
Despite efforts in treating water in water distribution systems, water borne disease outbreaks persist as a result of undergoing factors within the treatment tank, one of which is the water condition at the dead-end section. Existing models have addressed these problems in the mains and distribution, but that of dead end is still lagging. Therefore, this research seeks to address issue of water deterioration at the dead-end section of water distribution system of Abuja, Federal Capital territory of Nigeria. The Artificial Neural Network (ANN) model was deployed, for its ability to accurately model data of both short and long duration so as to establish dependability of the governing water quality parameters. The ANN models developed for training, testing, validation, and overall analysis indicated no significant variation between the predicted outputs and the original data values, demonstrating strong predictive capability and reliability. Among the different RANDIV distribution ratios examined, the 70:15:15 ratio produced better results for the Bayesian Regularization (BR), Levenberg-Marquardt (LM), and Scaled Conjugate Gradient (SCG) algorithms compared to the 80:10:10 and 60:20:20 ratios, with the BR algorithm showing superior overall performance. The ANN model equation, Output = 0.68(Target) + 0.02, showed close agreement between predicted and observed residual chlorine values, with only about 10 out of 259 data points exhibiting deviations up to 0.45%, while the majority differed by approximately 0.01%. The model achieved high reliability with R² values of 0.81 for training and between 0.62 and 0.75 for testing, validation, and overall datasets. Furthermore, the model-generated initial residual chlorine value of 0.02 mg/l complied with the USEPA recommended standard of less than 0.1 mg/l. The BR algorithm also demonstrated the best computational efficiency with a performance value of 0.0092 achieved within only 10 epochs, while LM and SCG required over 1000 epochs. The Nash-Sutcliffe Coefficient of Efficiency of 0.9236 (92.36%) further confirmed the accuracy and effectiveness of the developed model.EPANET simulations of the water distribution network revealed no significant chlorine loss around the dead-end sections, thereby maintaining acceptable residual chlorine concentrations and minimizing water quality deterioration. Simulations conducted over critical periods of 24 hours, 144 hours, and 240 hours demonstrated that the distribution system consistently maintained recommended chlorine residual levels under varying flow velocity, demand, and head conditions. Residual chlorine concentrations at selected dead-end nodes remained within safe operational limits, with a maximum value of 0.44 mg/l, which is below the recommended limit of 0.5 mg/l. The findings indicate that the distribution system is capable of preventing the growth and regrowth of disease-causing microorganisms while ensuring safe water quality throughout the network.
EFFECTS OF TEMPERATURE ON SOME SELECTED WOODS IN UMUAHIA, ABIA STATE
Wood has many helpful benefits, with high ratio of strength to weight and a remarkable record for durability and performance as a structural material, but the properties can be manipulated by the impact of environmental factors. Therefore, wood should be processed and stored adequately to uphold the value of the biomaterial. This work exposes the effects of temperature and relative humidity in the tropical environment of Umuahia on the storability of commonly available wood. Four of the most available wood samples, namely, Iroko, White Afara, Black Afara and Nauclea Diderrichi, were collected, fresh from the mill, and used for laboratory and field experiments to determine the moisture content and storage effects of wood as seen in conventional storage patterns adopted by regional timber dealers. The results showed that Nauclea Diderrichi wood has highest percentage of water absorption in the field by 7.94%, followed by Iroko with 5.93%, and Black Afara with 5.36%, while the lowest was White Afara with 4.63%. The level of absorption or percentage moisture contents in ascending order resulted to Iroko, White Afara, Black Afara and Nauclea Diderrichi was 2.81, 2.82. 2.88 and 3.5% respectively. The environmental factors, mainly, variation in temperature and relative humidity at different season, has effect on the length, width, thickness, volumes and moisture content of the wood samples as seen from the outcomes of the research.
PERFORMANCE EVALUATION OF AN IMPROVED CASSAVA PELLETING MACHINE
Pelleting is an important postharvest process that prepares agricultural products in cylindrical shaped forms for better storage, export and in the production of animal feed. The current high cost of feed has necessitated the crucial need to develop an efficient pelleting machine that will assist farmers to formulate their own feed for local consumption and export. The performance evaluation of an improved cassava pelletizer with mixing and conditioning section was evaluated at the operational speed of 250 rpm. The machine was powered by a 3.730 kW (5 h.p) electric gear motor and it comprises of hopper, barrel, mixer, screw conveyor, electric steam boiler, compression / extrusion plates, cutter, supporting frame and a power transmission unit. The extruding plate has die openings of 4 mm to produce the recommended cassava pellet size suitable for export. The average moisture content of the dewatered cassava mash used for the evaluation was 25 %. Also, the steam boiler used for the conditioning produced saturated steam at a temperature of about 103 oC. The result of the machine performance test indicates that the machine has average throughput capacity and efficiency of 151.74 kg/hr and 94.48 % respectively. The average diameter and length of the cassava pellet produced was 3.96 and 9.76 mm, respectively. The machine can be further optimized for cottage industry applications.
CRYOGENIC TREATMENT STRATEGIES AND ITS INFLUENCE ON THE MECHANICAL PROPERTIES OF STRUCTURAL STEEL GRADES
Cryogenic treatment (CT) is the post-treatment process applied after conventional heat treatment process in steel. It is a process of using materials (structural steel grades) at a very low temperature. It involves subjecting materials to an extreme low temperature. When structural steels are subjected to cryogenic treatment, it will improve the mechanical and physical properties of the steel. The noticeable enhancements observed in materials subjected to cryogenic treatment are increased thermal conductivity, increased in dimensional stability, toughness, increased in wear resistance, fatigue resistance, increased in hardness, reduce residual stress. The cryogenic treatment temperature at which hardened material is further cooled may range from -80℃ to -196℃. Cryogenic treatment helps in converting retained austenite to martensite and also refining of grain structure of structural steels. The aim of this paper is to carry out a review of cryogenic strategies and its influence on mechanical properties of structural steel grades. The review paper discussed cryogenic treatment procedure, comparison of various mechanical properties as well as influence of cryogenic treatment on structural steel grades.
EFFECTS OF FEED FORMULATIONS ON THE CHARACTERISTICS OF WATER TREATMENT RESIDUALS FROM FISH POND EFFLUENTS
Feed formulations play a significant role in determining the characteristics of water treatment residuals (WTRs) generated from fish pond effluents. Fish Pond Effluents can provide insights into the nature of the residue present, the objective of this study was to investigate the effects of different feed formulations on the nutrient content and pH of fish pond effluents. Two different feed formulations were used in the study: a low-protein feed and a high-protein feed. The Fish Pond Effluents were collected from fish ponds that were fed each of the two feed formulations. The nutrient content and pH of the fish were then analyzed. The results of the study showed that the feed formulation had a significant effect on the nutrient content and pH of the Fish Pond Effluents. The effluents from fish ponds that were fed the high-protein feed had a higher nutrient content and pH than the WTRs from fish ponds that were fed the low-protein feed. The findings of this study suggest that feed formulations can be used to manipulate the Fish Pond Effluents.
EVALUATION OF SOME PHYSICAL AND COMBUSTION PROPERTIES OF BIOMASS BRIQUETTES PRODUCED FROM DIFFERENT AGRICULTURAL WASTE MATERIALS AND THEIR BLENDS
This study evaluated some physical and combustion properties of briquettes produced from rice offal, sawdust, groundnut shell, and their blends to determine their suitability for clean energy and the benefits of blending. Biomass materials underwent size reduction, sieving (1 mm), moisture adjustment (8%), cassava starch binding (8%), uniform mixing, moulding, hydraulic compaction, and sun dried. Briquette quality was assessed using density, moisture content, ash content, calorific value, compressive strength, and burning rate. Results showed that rice offal briquettes had the highest ash content (22.73%) and lowest calorific value (14.15 MJ/kg), while groundnut shell briquettes recorded the highest energy value (18.89 MJ/kg) with moderate ash (5.23%). Sawdust briquettes exhibited the lowest ash content (2.40%) but the weakest compressive strength (0.06 N/mm²). Blending improved performance significantly: the ternary blend achieved the highest compressive strength (0.88 N/mm²) and stable density (0.58 g/cm³), while the groundnut shell–sawdust blend showed high calorific value (17.82 MJ/kg) and efficient combustion making it best for clean energy performance. ANOVA and Duncan Multiple Range Test (DMRT) indicated significant effects of feedstock on most parameters. The study demonstrates that agricultural residues can be converted into high quality briquettes, with blending enhancing overall fuel performance for sustainable energy applications.
EVALUATING THE COMPARATIVE THERMAL SENSITIVITY OF MORPHOLOGICAL PARAMETERS IN CUCUMBER (Cucumis sativus l.) UNDER GRADED NITROGEN AND PHOSPHORUS STRESS
Thermal infrared (TIR) imaging is a proven non-invasive technique for detecting abiotic stress in crops through canopy temperature variations; however, limited quantitative evidence exists on which morphological parameter exhibits the strongest thermal response. This study addressed this gap by evaluating four traits: leaf area, plant height, stem diameter, and number of leaves, in greenhouse-grown cucumber under graded nitrogen-phosphorus (N-P) stress over 44 days. A Randomized Complete Block Design (RCBD) with four blocks (A, B, C, D) and four treatments was used: T1 (120N/40P mg/kg), T2 (80N/30P), T3 (40N/20P), and T4 (0N/10P), with 12 replicates per treatment. Canopy temperature was measured using a calibrated UTi120s/FLIR thermal camera and processed in MATLAB, alongside periodic morphological measurements. Results showed that leaf area had the highest thermal sensitivity (F = 24.68, p < 0.001, R² = 0.5025), followed by stem diameter (F = 21.76, R² = 0.5890), number of leaves (F = 18.54, R² = 0.6697), and plant height (F = 15.82, R² = 0.6784). Maximum canopy temperature differences reached 7.1°C between T4 and T1. Tukey HSD analysis revealed that leaf area and stem diameter achieved significant discrimination in 5 of 6 treatment comparisons, including adjacent stress levels. These results establish leaf area as the primary determinant of thermal response, supporting its prioritization in precision nutrient monitoring systems.
PERFORMANCE EVALUATION OF A PALM KERNEL CRACKER WITH INTEGRATED SEPARATING UNIT
Nigeria as a country has not met the demand for palm kernel oil production because of the constraint involved in the processing operation especially, cracking and separation of shell from the nut. In this study, a palm kernel cracker (PKC) with a separating unit was developed. The separating unit consisted of three chambers where separation takes place: the first chamber removes the particles attached to the kernel and the shell, the second and central chamber removes the broken kernel and shell while the final chamber separates the cracked and uncracked kernel in a discharge chute by means of an attached blower. The developed PKC was tested using tenera and dura varieties of palm kernel. Performance indices for evaluation were cracking efficiency, throughput capacity and percentage losses using three moisture contents (A: 7.0 - 9.0; B: 10.0 - 12.0 and C: 14.0 - 16.0% d.b.) and four speeds of operation (1600, 2200, 2400 and 2600 rpm). The results showed that the highest cracking efficiency and output capacity for tenera were 87.3% and 51 kg/h respectively at 10 - 12% (d.b.) moisture content and speed of 2200 rpm while the highest cracking efficiency and output capacity for dura were 78.8% and 45 kg/h respectively at 10-12% (d.b.) moisture content and speed of 2200 rpm. The highest percentage loss (18%) obtained for tenera was at (14 - 16% d.b.) moisture content with an operating speed of 2400 rpm, while dura variety was 21% at same moisture content and operating speed. It could be concluded that the optimal performances of the PKC was at moisture content level 10 - 12% (d.b.) and operating speed of 2200 rpm for the two varieties of palm kernel tested.
COMPARATIVE PERFORMANCE ASSESSMENT OF SELECTED INFILTRATION MODELS FOR HYDROLOGICAL MODELING IN OWERRI IMO STATE, NIGERIA
Infiltration plays a critical role in hydrological modeling and irrigation system design, especially in regions with varying soil conditions and water management challenges. This study examines and evaluates the performance of three widely used infiltration models; Horton, Philip, and Green-Ampt using field data collected from Owerri North and Owerri West in Imo State, Nigeria. Soil analysis included particle size distribution, specific gravity, and moisture content. Infiltration rates were measured using a double-ring infiltrometer. Statistical tools such as coefficient of determination (R2), root mean square error (RMSE), and T-test were employed for model evaluation. Results indicated that the Green-Ampt Model offered the best predictive performance at both Orji and Ihiagwa, with closer agreement to measured infiltration rates, followed by the Philip model. Horton’s model consistently over-predicted infiltration. The research emphasizes the importance of site-specific model selection in hydrological modelling for improved water resource management.
COMPARATIVE EVALUATION OF CHICKEN AND TURKEY MANURE ON SOIL HYDRAULIC PROPERTIES IN SANDY LOAM SOIL
This study described the response of soil hydraulic parameters to chicken and turkey manure. A soil-manure mix ratio of 5:1 was used for the experiment. Samples were labelled CMM for chicken manure and TMM for turkey manure. A third sample without manure was labelled control. All soil samples were kept under a controlled environment for 12 weeks. Soil samples were collected and analyzed at intervals of 4 weeks for bulk density, saturated hydraulic conductivity (Ksat), water retention capacity (WHC), and total organic carbon (TOC). Soil textural properties and manure nutrient composition were also analyzed. Standard methods were used for all analyses. Results show that the soil is of loamy sand textural classification and that both amendment materials improved bulk density significantly <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>p</m:r><m:r><0.001)</m:r></m:oMath><![endif]--> <span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; position: relative; top: 4.0pt; mso-text-raise: -4.0pt; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> relative to the control. The mean bulk densities (CMM – 1.25 g/cm3; TMM – 1.19 g/cm3) were found to be within the recommended values for loamy soils. Although the amendments changed WHC and Ksat values, the difference compared to the reference soil was not significant <!-- [if gte msEquation 12]><m:oMath><m:d><m:dPr><m:ctrlPr></m:ctrlPr></m:dPr><m:e><m:r>p</m:r><m:r>>0.05</m:r></m:e></m:d><m:r>. </m:r></m:oMath><![endif]--> <span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; position: relative; top: 4.0pt; mso-text-raise: -4.0pt; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> Mean values of bulk density, WHC (<!-- [if gte msEquation 12]><m:oMath><m:r><90%)</m:r></m:oMath><![endif]--> <span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; position: relative; top: 4.0pt; mso-text-raise: -4.0pt; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> , and Ksat (22.06 cm/day) of the amended soils indicate that both manures improve soil hydraulic and organic matter properties, and selection between the them will depend on availability.
EFFECTS OF TOPO POSITION ON PHYSICO-CHEMICAL PROPERTIES OF THE SOIL AT EZEAGU AREA OF ENUGU STATE, SOUTHEASTERN NIGERIA.
Topographic position is a key landscape control on soil redistribution and the spatial organization of soil physicochemical properties along hillslopes. This study examined the influence of topo-position (upper, middle, and bottom slopes) on selected soil physico-chemical properties in Olo, Ezeagu Local Government Area, Enugu State, Southeastern Nigeria. A stratified transect sampling design was applied across three representative topo positions. Transects extended from crest to foot slope and soil samples were collected at a uniform depth of 0 – 20 cm using a stainless steel, soil auger and core samplers at 20 m intervals. A total of 27 disturbed and undisturbed soil samples were collected at Nine sampling points on each topo position. The samples were subjected to laboratory analyses using standard procedures, and data were evaluated using Analysis of Variance and correlation analysis with spatial variability discussed using Coefficients of Variation (CV). Results showed systematic topo position controls on soil physico-chemical properties. Particle Size Distribution showed low variability (CV < 15%) with sand content decreasing downslope (24.70–20.40%) and clay content increasing (39.90–44.80%). Bulk Density and total porosity also exhibited low variability (CV < 2%), declining downslope from 1.35 to 1.31 g cm⁻³ and increasing from 48.93 to 50.52%, respectively reflecting relatively uniform soil structural conditions across the topo positions. Soil pH showed low variability (CV = 5.27%) and increased downslope from moderately to slightly acidic conditions (5.77–6.40). Organic Carbon displayed moderate variability (CV ≈ 21%), which was highest at the middle slope (1.09%), suggesting partial deposition and stabilization zones. In contrast, total nitrogen (CV = 51.70%) and Available Phosphorus (CV = 82.65%) exhibited high variability with pronounced downslope declines from 0.18% to 0.07% and from 11.20 to 2.80 mg kg⁻¹ respectively. This shows strong sensitivity of nutrient pools to slope-driven redistribution. Cation exchange capacity showed low variability (CV < 10%) and was highest at the middle slope (5.60 cmol kg⁻¹). These findings emphasize that topo-position exerts strong control over both physical redistribution and chemical differentiation along the hillslope.
PERFORMANCE EVALUATION OF ANAEROBIC CO-DIGESTION OF PIG DUNG AND POULTRY DROPPINGS FOR BIOGAS PRODUCTION IN A BATCH DIGESTION SYSTEM
The rapid expansion of livestock production in Nigeria has led to the generation of large quantities of organic waste, presenting significant environmental and waste management challenges. Anaerobic co-digestion offers a sustainable approach for converting mixed livestock wastes into renewable biogas while simultaneously addressing waste disposal concerns. This study evaluated the biogas production performance of co-digested pig dung and poultry droppings at Vision Farm, Ogbeke Nike, Enugu State, Nigeria (6.52°N, 7.55°E). A batch anaerobic digestion experiment was conducted using a 3.5 m³ PVC biodigester. The digester was charged with 656.26 kg of mixed substrates diluted with 1968.75 L of water at a water to waste ratio of 3:1, with 75% of the digester volume occupied by slurry and the remaining 25% serving as gas headspace. Biogas production was monitored daily for 30 days using the water displacement method. Ambient temperature, slurry temperature, and slurry pH were recorded daily. Cumulative biogas production reached 6452.6 L with an average daily yield of 215.1 Ld⁻¹. Peak production of 571.5 L was recorded on day 14. Ambient temperature ranged from 30.5 - 37.0 °C, slurry temperature from 35.0 - 47.0 °C, and pH from 6.03 to 6.90, all consistent with favorable mesophilic conditions for methanogenic microbial activity. Flammable gas was confirmed from day 8, indicating active methane formation. These results demonstrate that anaerobic codigestion of pig and poultry wastes can effectively generate renewable energy for farm applications under tropical conditions.
PERFORMANCE EVALUATION OF A MOTORIZED COCOYAM CHIPPING MACHINE
The performance of a motorized cocoyam chipping machine developed at the National Root Crops Research Institute, Umudike was evaluated. The machine comprises of the following major parts namely, the main frame, housing, chipping plate and the power transmission unit. Two varieties of cocoyam tubers from Colocasia esculenta species, NCe 001 (coco India) with average geometric mean diameter (3.20 cm), sphericity (0.81), weight (98.05 g), moisture content (48.97 %) and NCe 002 (ede ofe green) with the average geometric mean diameter (3.42 cm), sphericity (0.76), weight (87.14 g), moisture content (52.06 %) were used for the evaluation. The machine was evaluated using 5 kg of cocoyam tubers for capacity and efficiency at five varying speeds of 300, 325, 350, 375 and 400 rpm. The results obtained showed that the capacity of the machine increases with the speed, while the efficiency increases with speed up to 375 rpm, but beyond that level, it drops. The highest capacity of 195.04 kg/hr was obtained at speed of 400 rpm, but 92 % efficiency was obtained at 375 rpm. Evaluation of the effect of feed rates and chute clearance on the capacity of the chipper was also carried out using Analysis of Variance (ANOVA) in 3 x 5 factorial with three levels of feeding chute clearance (0.07, 0.09 and 0.12 m) and five levels of feed rate (2.5, 2.8, 3.0, 3.2 and 3.5 kg/min) in a Randomized Complete Block Design (RCBD). The results of the statistical analysis showed that both the feed rate from 2.5 to 3.5 kg/min and the chute clearance from 0.07 to 0.12 m had a highly significant effect at 1% level on the capacity of the chipper
BIOREMEDIATION OF TOTAL MONOCYCLIC AROMATIC HYDROCARBONS IN OIL-BASED DRILL CUTTINGS USING POWDERED
Oil-based drill cuttings (OBDCs) contain high concentrations of toxic total monocyclic aromatic hydrocarbons (TMAHs), making them among the most hazardous wastes produced during petroleum exploration. This study evaluated the potential of powdered Eichhornia crassipes as a natural organic amendment for enhancing the bioremediation of TMAHs in OBDCs. A completely randomized design (CRD) with five treatment levels was adopted, consisting of a control (0 g) and four amendment levels (30 g, 50 g, 70 g, and 90 g) of dried water hyacinth powder mixed with 1000 g of loamy soil and 500 g of contaminated drill cuttings. Total heterotrophic bacteria (THB), soil pH, and TMAH concentrations were monitored throughout a 50-day aerobic remediation period. Results showed a significant increase in microbial activity in the amended treatments, with THB counts of (3.95 × 10³ cfu/g) reaching their peak on Day 30. The highest reduction in TMAH concentration (96.36%) occurred in the 90 g treatment, while the control recorded only 30.48% reduction. The amendment also helped maintain a favourable soil pH for microbial activity. Statistical analysis indicated that amendment dosage and remediation period significantly affected remediation efficiency (p < 0.05). These findings demonstrate that Eichhornia crassipes can serve as a cost-effective and environmentally sustainable amendment for remediating hydrocarbon-contaminated soils.
INFLUENCE OF COARSE AGGREGATE SHAPES ON THE WORKABILITY AND STRENGTH OF CONCRETE
This study investigated the effect of coarse aggregate shape on the compressive strength and density of concrete. Five aggregate types—angular, elongated, smooth-rounded, flaky, and a control mix—were used to cast 60 concrete cubes using a 1:3:6 mix ratio and a water-cement ratio of 0.5. The cubes were cured for 7, 14, 21, and 28 days, after which their average compressive strength and density were determined. The results showed that compressive strength for all aggregate types increased with curing age. The control aggregate produced the highest strength values, reaching 26.01 N/mm² at 28 days, followed by angular and flaky aggregates, which achieved 18.28 N/mm² and 18.16 N/mm², respectively. Elongated and smooth rounded aggregates yielded lower 28-day strengths of 16.36 N/mm² and 16.98 N/mm². Density measurements also varied with aggregate shape and curing time, ranging from approximately 2099 kg/m³ to 2432 kg/m³. The study concludes that aggregate shape significantly influences concrete properties, with angular and control aggregates providing superior compressive strength compared to other shapes.
TRANSPORTATION CHALLENGES IN POSTHARVEST HANDLING: IMPLICATIONS FOR QUALITY, SAFETY, AND LOSSES OF AGRICULTURAL PRODUCTS IN DEVELOPING NATIONS
This study examines the impacts of transportation on post-harvest quality of agricultural products, particularly focusing on the effect of poor transport systems on products’ deterioration and economic losses. A systematic review of related literature on the subject was utilized in this work. Evidence from the scholarly materials points to the fact that freshness, safety, and marketability of agricultural products are all impacted by transportation, which is an essential link between producing locations, storage facilities, and marketplaces. Conversely, in Nigeria, transportation-related problems in agricultural production include poor road networks, insufficient logistics organization, inadequate cold-chain facilities, and lack of handling facilities. These had resulted in substantial post-harvest losses, especially for perishable farm products like fruits, roots, vegetables, fish and animal products. These elements lower the nutritional and aesthetic value of produce by causing biochemical deterioration, microbial infection, and mechanical damage. The study also revealed that enhancing packaging systems, temperature control, and transportation infrastructure are important ways to reduce losses. Ultimately, the research concludes that well-organized and sustainable transportation structures are essential to improving agricultural products’ nutritional quality, storability, and profitability for economic growth and food security.
DESIGN, FABRICATION AND PERFORMANCE EVALUATION OF A GROUNDNUT CAKE EXTRUDER WITH VARIABLE DIE GEOMETRY
Groundnut cake (kulikuli) is a protein-rich snack widely consumed in Nigeria, but its traditional production methods are labor-intensive, unhygienic and unsuitable for large-scale processing. This study presents the design, fabrication and performance evaluation of a locally developed groundnut cake extruder equipped with variable die geometry. A single-screw extruder was designed and fabricated using locally available materials and fitted with three interchangeable die shapes: circular, square and inverted (which is a die whose opening is shaped in a reversed orientation influencing the shape and physical properties of the extruded groundnut cake). A randomized experimental design was employed to evaluate the effects of screw speed (7 rpm, 9 rpm and 11 rpm), moisture content (5.04%, 7.04% and 10.65%) and die shape on extrusion performance and product quality. Statistical analysis was carried out using Response Surface Methodology (RSM) and Analysis of Variance (ANOVA). Results indicated that screw speed, moisture content and die shape significantly influenced extrusion capacity, bulk density, expansion ratio and specific length of the extrudates (P < 0.05). Model adequacy and predictive capability were confirmed using coefficients of determination (R² ≥ 0.60), adjusted and predicted R², adequate precision ratios and error analysis parameters. The extruder recorded an average extrusion capacity of 12.30 kg/h with high extruding and cutting efficiencies. Optimum performance was achieved at a screw speed of 9 rpm, moisture content of 7.04%, and circular die shape, which produced groundnut cake with relatively low bulk density, improved expansion ratio, uniform shape and stable extrusion flow. The results demonstrate that the designed and fabricated machine is suitable for hygienic, efficient and small-to-medium scale production of groundnut cake.
MODELING OF RAINFALL-RUNOFF RELATIONSHIP IN ABIA AND IMO STATE, NIGERIA
Rainfall–runoff relationships play a critical role in hydrological analysis, flood prediction, erosion control, and water resources management, particularly in humid tropical environments such as Nigeria. This study evaluated the relationship between rainfall and runoff in Abia and Imo states, southeastern Nigeria, using long-term hydro-meteorological data spanning 25 years (1984–2009). Rainfall and associated climatological variables were analyzed, and runoff was estimated using two modelling approaches: linear regression analysis and fuzzy logic modelling. Monthly rainfall exhibited a distinct seasonal pattern, with peak values occurring between June and September, corresponding to higher runoff generation. Model performance assessment revealed that both approaches adequately simulated runoff responses; however, the fuzzy logic model demonstrated superior predictive capability with a lower average relative error of 13.40%, compared to 21.07% obtained from the regression model. The results confirm rainfall as the dominant factor influencing runoff generation in the study area and highlight the effectiveness of fuzzy logic techniques in capturing nonlinearity and uncertainty inherent in hydrological systems. The developed models provide a reliable framework for runoff prediction and can support erosion control planning, flood mitigation, and sustainable water resource management in southeastern Nigeria.
KINETIC EVALUATION OF THE EPOXIDATION OF LUFFA CYLINDRICA M. SEED OIL UTILIZING LUFFA FIBRE CATALYST
The catalytic valorization of biomass offers a sustainable route for bio-epoxide production. Conventional epoxides produced with non-renewable catalysts pose environmental risks, exhibit poor biodegradability, and incur high production costs. However, Luffa cylindrica fibres have not been explored as precursors for heterogeneous epoxidation catalysts, and the epoxidation of luffa seed oil under catalytic kinetic regimes remains under-investigated. In this study, luffa fibre was sulfonated and converted into a heterogeneous nanocatalyst for the epoxidation of oleic-rich luffa seed oil (LSO). Catalyst activation increased the BET surface area from 294.28 to 353.29 m² g⁻¹ and expanded pore size from 2.69 to 3.13 nm, enhancing reactant diffusion and active site accessibility. Scanning Electron Microscopy (SEM) revealed nano-scale spherical agglomerates, while XRD confirmed crystallite formation (~45 nm) and improved lattice ordering. Fourier Transform Infra-Red (FT-IR) analysis verified the presence of acidic functional groups, and TGA demonstrated thermal stability up to ~420°C. Epoxidation achieved a maximum oxirane value of 5.21 mol at 65°C. Kinetic analysis showed pseudo-first-order behavior with rate constants of 0.0392–0.222 h⁻¹ between 328–338 K, while thermodynamic parameters (Ea = 14.44 kJ mol⁻¹; ΔH = 14.44 kJ mol⁻¹; ΔS = −21.75 cal mol⁻¹ K⁻¹) indicate an endothermic and ordered transition state.
A COMPARATIVE STUDY ON CRUDE OIL DEGRADATION DYNAMICS IN SALTWATER AND FRESHWATER UNDER BATCH REACTOR CONDITIONS
The fate of crude oil in stagnant aquatic systems was investigated through laboratory experiments supported by mathematical modeling. Two cylindrical batch reactors of equal capacity were filled with 1.5 m³ of freshwater and saltwater, and each system was contaminated with 250 cm³ of crude oil. Six control valves were installed at uniform depth intervals for sequential sampling over a 42-day period at 7-day intervals. Physicochemical parameters, Total Bacterial Counts (TBC), and Total Petroleum Hydrocarbon (TPH) concentrations were assessed. Modeling of hydrocarbon dispersion and degradation was performed using a developed Dispersion–Degradation Model incorporating both first-order biodegradation kinetics and Monod parameters. TBC increased progressively in both systems, with a slow microbial response in saltwater until day 26, followed by exponential growth in both water types between days 35 and 40. First-order kinetic degradation rates (kd) were 0.0034 day⁻¹ in freshwater and 0.00213 day⁻¹ in saltwater, showing greater microbial degradation in freshwater. Monod-based model predictions deviated significantly from measured TPH data, while first-order kinetics closely correlated with experimental values. Findings suggest that crude oil breakdown is more efficient in freshwater due to reduced microbial inhibition relative to salinity effects. The study provides essential information for decision-making on remediation technologies in freshwater versus marine spill sites.
EFFECT OF SODIUM CHLORIDE CONCENTRATION ON THE SHORT-TERM PRESERVATION OF COW, GOAT, AND SOY MILK
storage was investigated. Fresh milk samples were pasteurized at 72 oC and NaCl at concentrations of 0.004, 0.008, 0.012, and 0.016 g/ml were added at three replicates, then stored for five days under controlled conditions. Parameters evaluated included boiling point elevation, pH, viscosity, and electrical conductivity. Boiling point elevation increased progressively with NaCl concentration, reaching maximum values of approximately 19°C in Cow milk, 17.4°C in Goat milk, and 14.4°C in Soy milk at the highest concentration by Day 5, indicating enhanced thermal stability. pH trend was dependent on the milk type that is dairy and plant milk. Cow and Goat milk exhibited increasing pH during storage, whereas Soy milk showed acidification. Statistical analysis showed that NaCl had no significant effect on pH (p > 0.05), suggesting that storage time and intrinsic milk composition were dominant factors. Viscosity increased in all milk types over time, but higher NaCl concentrations significantly moderated viscosity development in Soy and Goat milk (p < 0.05), whereas Cow milk viscosity was less affected. Electrical conductivity increased remarkably with NaCl concentration (p < 0.001), reflecting enhanced ionic content, with Soy milk exhibiting the highest values. These results demonstrate that sodium chloride modifies thermal stability, flow behavior, and ionic characteristics of both dairy and plant-based milk systems. The study highlights NaCl’s effectiveness as a preservative while emphasizing the need for optimized concentrations to maintain quality and minimize adverse effects on the properties studied.
INFLUENCE OF HYDROPHOBIC FLUID (PALM OIL) VARIETIES ON HYGROSCOPIC POTENTIALS OF FOUR VARIETIES OF CASSAVA GARRI AT VARYING STORAGE TEMPERATURES
This study examined the effects of palm oil varieties (Dura and Pisfera) and their quantities (15 ml, 30 ml, and 45 ml) on the hygroscopic properties of four garri varieties (Poundable, Gamechanger, TMS 1632, and TME 419) at temperatures of 35°C, 45°C, and 55°C. Moisture absorption was assessed by placing 5 g samples of each garri in water baths set at the specified temperatures. The weight of each sample was measured at 30-minute intervals until three consecutive measurements indicated equilibrium. Results revealed that palm oil significantly (p<0.05) reduced moisture absorption across all samples, with Dura oil generally providing a more effective moisture barrier than Pisfera. At 45 ml, Dura oil caused a slight increase (11.63%) in moisture uptake, suggesting saturation, while Pisfera stabilized, indicating different chemical interactions. TME 419 exhibited the lowest (1.8%) moisture absorption, demonstrating superior resistance, whereas TMS 1632 absorbed the most moisture. Elevated temperatures increased moisture uptake, especially in control samples without oil. Kinetic parameters (absorption rate constant, K1 and absorption capacity, K2) varied with temperature and variety, reflecting changes in diffusion rates. The K1 for Pisfera oil decreased from 19.67358 at 35°C to 7.388 at 55°C, while Dura oil decreased from 17.41483 to 10.866 over the same temperature range; conversely, K2 for Pisfera increased from 0.058013 to 0.096799, whereas Dura’s capacity decreased from 0.112241 to 0.058681 with rising temperature. Activation energy analyses showed Dura oil created a more resistant barrier, with values of 1.21 J/mol (TMS 1632), -0.5595 J/mol (TME 419), -0.4489 J/mol (Poundable), and 1.45 J/mol (Gamechanger). The findings suggest that palm oil improves garri’s moisture resistance, with Dura oil being more effective, especially at lower quantities, informing optimal storage practices in humid environments.