School of Science and Technology
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Welcome to School of Sciences and Technology collection.This collection contains Journal articles published by faculty affiliated to the school.
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Item THE CONTAMINATING EFFECTS OF COFFEE PROCESSING HONEY WATER, CASE OF OTHAYA COFFEE SOCIETY, NYERI COUNTY, KENYA(International Journal of Agriculture and Environmental Research, 2024-05) Mutua, Paul Mbua; Muchiri, John Munderu; Mugambi, MworiaKenya's economic growth heavily relies on agriculture, with coffee production being a key subsector. Coffee processing consumes significant surface water, generating coffee honey water as a by-product, which contaminates downstream water sources and affects local communities. This study aimed to assess the contaminating effects of coffee honey water on surface waters, determine contaminant levels, evaluate pollutant impacts, and analyze socio-economic effects on the population. A mixed research design was employed; involving four experimental blocks with three treatments per block, utilizing a total squares randomized design with four replicates to minimize variability. Twelve surface water samples were collected from upstream, interception, and downstream points, along with four untreated coffee honey water samples from lagoons. The physicochemical properties of these 16 samples were analyzed. Additionally, descriptive statistics from closed and open-ended questionnaires involving 79 respondents from the Othaya Coffee Society Management and 30 local households were analyzed. Findings indicated negative impacts on local communities due to water pollution from coffee processing, with high acidity, organic matter, nutrients, and suspended solids degrading water quality. The study concluded that effluents from wet coffee processing did not meet WHO standards for treated effluent discharge. Recommendations included ensuring treatment of coffee effluents before discharge, implementing proper wastewater treatment facilities in coffee industries, and enforcing regulations by authorities like NEMA. Further research is recommended to explore the effects of coffee pulp on water contamination and the impact of city planning policies on wastewater management in industrial areas such as Othaya town.Item Fundamental Concepts Underlying Strutural Activities of Selected Trees’ Roots on the Performance of the Adjacent Native Grass Pastures(International Journal of All Research Education and Scientific Methods, 2022-10) Mwangi, Gichuki P.; Muchiri, John; Mugambi, MworiaTree root growth structure is a major pathway of enhancing uptake of water and minerals salts to the soil. The main objective of the study was to evaluate the fundamental concept underlying structural activities of selected trees’ roots on the performance of the adjacent native grass pastures. The study evaluated the effect of tree stand from a distance of 1, 10, 20,30,40,50 and 60m. A vertical removal of top soil up to 60cm was done. Using vertical soil profile exposed after removal of soil, a small grid cell measures 5x5cm was used to mark the area where roots were exposed. A small knife was used to remove the surrounding soil. The exposed roots were counted inside the area marked by the grid cell. The number of intersection roots of diameters (fine roots between 0.1-1mm,medium roots 1mm-1cm and large diameter roots over 1cm) were manually counted. To the obtain the above ground grass biomass, a radial circle sampling method was used with a radius of 1m all around the marked points in the direction of 0°, 45°, 90°, 135°, 180°, 225°, 270° and 315°. A quadrat 0.25m2 was laid on each direction and grass samples were collected inside the quadrat. Each marked points (1, 10, 20, 30, 40, 50 and 60m); a serrated knife was used to harvest the grasses that grow the area surrounded by the quadrat. The harvested grass samples were put carefully in labelled bag that included quadrat number and the area collected. The results of the study show that tree root growth morphology influences resource supply to the adjacent native grass pastures. The findings is thought to provide valuable information to National Environmental Management Authority (NEMA), community leaders, extension officers, farmers and NGOsItem Effects of over story Tree Litter Quality on Nutrient Release Pattern to the Understory Native Grass Species(World Journal of Innovative Research, 2022-10) Mwangi, Gichuki P.; Mugambi, Mworia; Muchiri, JohnTree litter falls is a major pathway of enhancing nutrients cycling to the understory grass vegetation. The main objective of the study was to evaluate the effects of over-story tree litter quality on nutrient release pattern to the under-story native grass species. A composite sample of freshly fallen leaves was collected. Leaf samples were homogenously mixed and put in nylon litter bags of 2mm mesh size and 25g weight. Each 7 marked points (1, 10, 20, 30, 40, 50 and 60m) had 3 samples litter bag weighing 25g. A total of 84 litter bags were collected from the adjacent pastures which include 21 litter bags from Eucalyptus, 21 litter bags from Acacia, 21 litter bags from Cypress and 21 samples litter bags from the control. They were taken to the laboratory for litter analysis and later reburied back to the points where they were collected. They were first retrieved from the points they were buried at the end of dry season and later at the end of wet season. Data was summarized using excel package and then analyzed using Statistical Package for Social Sciences (SPSS) for window version 22. All the hypotheses was tested at α=0.05. The results of the study show that tree litter quality influences resource supply to the understory native grass pastures. The findings is thought to provide valuable information to National Environmental Management Authority (NEMA), community leaders, Kenya Forestry Services (KFS), opinion leaders, extension officers, farmers and NGOs.Item Effect of Phosphorus Application on Yield of Sweet Potatoes in Embu West Sub-County, Kenya(African Journal of Agriculture and Food Science, 2022-10) Wanja, Mugai Tabitha; Mugambi, Mworia; Koome, MartinSweet potato is a crop that plays a great role in food security in Kenya since it is a drought resistant crop, takes a short time to mature and is highly flexible. The main economic activity in Embu West Sub County is agriculture, which is the economic pillar of Embu County with most farmers there being small scale farmers and depending on this sector for their livelihood. Phosphorus as a plant nutrient is a key component of several chemical compounds necessary for metabolic activities, flowering, and root development; hence, it is essential for proper plants growth including sweet potatoes. This study purposed to evaluate how P application affects yield of three sweet potato varieties in Embu West Sub County. The sweet potato varieties used were SPK004 (V1), Kenspot 3 (V2) and Kenspot 4 (V3). The P fertilizer levels used were 0 kg/ha (P1), 25 kg/ha (P2), 50 kg/ha (P3), and 75 kg/ha (P4). Data on two specific yield parameters was collected at harvest; the collected data was summarized using excel. Analysis of variance of the data was done using SPSS version 23, at α=0.05. For treatment means that were significantly different, LSD as Post hoc test was used to separate them. The study showed significant yield potential difference in the yield parameters among the three sweet potato varieties with Kenspot 4 being the highest producer of both total and marketable tubers yield. The study showed that the amount of P applied significantly affected yield of sweet potatoes with a P level of 50 kg/ha producing significantly higher yields.Item Chemical composition of Moringa oleifera Lam. and Moringa stenopetala Bac. leaves from Kenya(International Journal of Plant Research, 2020) Nathaniel, Ebenezer Udofia; Onyancha, Jared Misonge; Mugambi, Mworia; Ncene, William; Moriasi, Gervason ApiriThe species of Moringa are native to India and Africa. However, they are cultivated in Tropical and sub-tropical countries mainly for nutrition and health products. In Kenya, most research has been done on M. oleifera and little on M. stenopetala. The paucity of consistent information of comprehensive chemical composition of the two species is generally observed. The purpose of this study was to find out the phytochemical and nutritive elements in M. oleifera and M. stenopetala collected from Kilifi and Isiolo counties in Kenya respectively. Standard chemical evaluation methods were used to establish qualitative and quantitative chemical composition of the two species in this study. Qualitative screening revealed alkaloids, cardiac glycosides, flavonoids, phenolics, phytosterols, saponins, tannins, coumarins, terpenoids, carbohydrates, proteins, lipids and vitamins. Proximate chemical composition revealed significant difference in composition of carbohydrates, flavonoids, phenols, alkaloids, saponins ash and crude fibre between M. oleifera and M. stenopetala leaf powder at p ≤ 0.05. However, there were no remarkable differences in the composition of crude lipids, crude proteins and moisture content in the leaf powders of M. oleifera and M. stenopetala. The study revealed essential and non-essential amino acids and no significant differences in composition at p ≤ 0.05 between the leaf powders of M. oleifera and M. stenopetala. Remarkable differences in composition of Thiamine (Vitamin B1) between M. oleifera and M. stenopetala were also noted (p < 0.05). However, there were no difference in composition vitamins (B6, B9, A and C) between the leaf powder of M. oleifera and M. stenopetala at (p < 0.05). Finally, the composition differences of calcium and potassium were significant between M. oleifera and M. stenopetala leaf powders at (p < 0.05), while there were no outstanding differences in the composition of copper, manganese, iron, zinc, magnesium and potassium between M. oleifera and M. stenopetala leaf powders.Item Growth Performance of Broilers Fed on Processed Acacia Tortilis Seed Meal as a Replacement of Soya Bean Meal(International Journal of professional Practice (IJPP), 2021) Ikiamba, Lawrence M.; Ncene, William; Mugambi, MworiaChicken is a major source of protein to humans and a regular income earner to the farmer. Acacia tortilis seeds meal is a key diet in poultry farming. This study sought to determine the growth performance of broiler chicken fed on processed Acacia tortilis seed meal as a replacement of soya bean meal. The study employed a Completely Randomized Design (CRD), and aimed at achieving the following specific Objectives: to determine the growth performance of broilers fed on processed Acacia Tortilis seed meal as a substitute of Soya bean meal; to determine carcass characteristics of broilers fed on processed Acacia Tortilis seed meal as a substitute of Soya bean meal; and to determine the economic benefit when broilers are fed on diets containing processed Acacia Tortilis seed meal as a substitute of Soya bean meal. The study adopted an experimental methodology. The broiler chicks were randomly assigned to six treatments, with three (3) replication (five birds per cubicle). The replacement feed levels; T0Control 0% acacia + 100% soybean, T1-20% acacia + 80% soybean, T2- 40% acacia + 60% soybean T3- 60% acacia+ 40% soybean, T4 - 80% acacia + 20% soybean and T5 - 100% acacia+0% soybean in a deep litter rearing system. Ninety-day old broiler chicks of mixed sex were experimented. The chicks were fed on broiler starter for 7 days and on experimental diet from day 8-35. The feed and water was provided ad libitum. Data collected was summarized and organized in excel. SPSS software was used to carry out Analysis of Variance (ANOVA), using the predictive analysis software version 20. The initial body weight was not significant (p > 0.05). The Final weight gain, Daily weight gain, Body weight Change was significant and biomass harvested was significant (p < 0.05), where T1 was the highest, followed by T2, T0, T3, T4 and T5 in that order. Voluntary feed intake was not significant (p > 0.05), showing that this ration was palatable and acceptable by the birds. Feed conversion ratio (FCR), T1 was the lowest and was significant (p < 0.05) and T5 was the highest. The higher the FCR the lesser desirable the feed is. It is recommended that Acacia tortilis seed meal of up to 40% can be included in chicken diet as a substitute of Soybean meal but optimally at 20%.