Department of Environmental Studies

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Influence of Variation in Biophysical Factors On Tree Species Structure and Composition in Kapseret Forest, Uasin Gishu County, Kenya
(Chuka University, 2022) Kutuny, G.K.; Rithaa, J. N.; Mutuma, E.
Forests are important for survival and development of human and other fauna. However, they are under degradation due to changes in biophysical factors which affects tree species structure and composition. Understanding these variations and their influence on tree species structure and composition guides conservation of forest. This study aimed at assessing the influence of variation in biophysical factors on tree species structure and composition. Ecological survey was used whereby, tree species and soil samples were studied from 12 sample plots identified through stratified sampling techniques within Kapseret forest. Tree species were enumerated and recorded by species name and Diameter at Breast Height (DBH), those with ≥3m height and DBH > 9.5 cm were classified as trees, while those with ≤3m height and less than DBH ≤ 9.5cm were recorded as saplings. Tree species attributes assessed included: tree DBH and diversity, while biophysical variables measured were: soil organic carbon (SOC), soil texture, phosphorous and potassium. A total of 148 tree species were identified with 62.16% being saplings while 35.14% were mature trees. The CCA results indicated positive correlation between tree species diversity with variation in biophysical factors, the presence of gaps with high P levels were associated with majority of the saplings, however, the DBH class distribution did not indicate an inverse J-shape portraying high degradation. The tree species-biophysical factors should therefore be utilized with other environmental factors such as topography,light intensity,temperature and wind when planning and choosing species for rehabilitation and restoration of degraded landscapes.
Assessment of Benthic Macroinvertebrates as Bioindicators of Water Quality in River Naka, Chuka, Tharaka-Nithi, Kenya
(Chuka University, 2022) Chamia, L.K.; Kutuny, G.K.
Freshwater ecosystems worldwide have been progressively deteriorating leading to a decrease in aquatic biodiversity. Conventionally, evaluation of water quality uses single physical-chemical parameters which may be insufficient to fully assess the quality of freshwaters. This study used bio-indicators to assess water quality of River Naka in Tharaka-Nithi County, Kenya. Fluvial ecosystems support rich and diverse assemblages, making them vulnerable to possible alterations in the habitat. The study assessed the diversity and abundance of benthic macroinvertebrate communities and their use as bioindicators of water quality. Grab sampling was used to collect water samples, a kick sampler and D-frame aquatic net was used to collect 121 benthic macroinvertebrates from three selected sites and determined using EPT Index (Ephemeroptera, Plecoptera and Trichoptera group). The data obtained was used to determine the index of the sampling sites. Physico-chemical factors were analyzed in-situ (temperature, turbidity and pH) and in the laboratory(nitrates and phosphates). The highest EPT index values (28) at the upstream corresponded to good water quality, while the slightly low values (21) at the midstream indicated moderate water quality and the lowest values (15) recorded at the downstream showed fair water quality. The downstream water quality parameters exceeded World Health Organization limits, posing a health risk to water consumers. Continuous bio-assessment of rivers based on EPT biotic indicators should be conducted on a regular basis to establish a long-term profile of water quality state and ecological integrity of rivers.
Use of Magnetic Fields Reduces α-chaconine, α-solanine, and Total Glycoalkaloids in Stored Potatoes (Solanum tuberosum L.)
(Wiley Periodicals LLC., 2022) Irungu, F. G.; Tanga, C. M.; Ndiritu, F. G.; Mwaura, L.; Moyo, M.; Mahungu, S. M.
This work aimed to assess the suitability of magnetic fields (MF) to reduce glycoal- kaloids (GAs) in stored potatoes. The effects of the source of magnetic fields (direct current [DC] and alternating current [AC]), magnetic field intensity (1, 2, and 3 mT), and storage type (dark store—herein referred to as the control store and a commercial store with varying light intensity) on quantities of GAs were investigated. Subjecting tubers to increasing levels of MF intensities and placing them in the control store led to a significant (p < .05) decrease in α-chaconine and an increase in α-solanine. However, storage of potatoes in the commercial store after exposure to increasing MF intensities led to a significant (p < .05) decrease in α-solanine and an increase in α- chaconine. The use of AC MF with an intensity of 2 mT resulted in a significant (p < .05) reduction in α-chaconine, α-solanine, and TG. Novelty impact statement: Magnetic fields are an emerging non-thermal technology that has wide potential in food processing applications. The findings in the current work revealed that magnetic fields can be used to reduce quantities of toxic glycoal- kaloids in potatoes during storage, and thus improve their postharvest quality. The results offer practical insights on postharvest management of potatoes to ensure re- duction of losses and thus positively impact food and nutritional security.
Pesticides’ use and their management practices among farmers in Mutarakwa division of Bomet county, Kenya
(International Journal of Agriculture and Environmental Research, 2017-06) Njeru, Moses Kathuri
The demand for food has increased tremendously over the years as the population grows. To meet this high demand for food, intensified agriculture has been prioritised. However, the resulting high crops yields are threatened by incidences of pests and diseases either at growing stage or at storage. To counter the loss associated with pests and diseases, the development and intensified use of pesticides has become imperative. This paper examines pesticides management practices in Mutatarakwa division in Bomet County, Kenya.
Plasmid sequence dataset of multidrug-resistant Enterobacterales isolated from hospital effiuents and wastewater treatment plant
(Elsevier Inc., 2022-11-09) Mutuku, Christopher, Barbara Kutasy, Peter Urban, Szilvia Meleghd, Robert Herczeg, Zoltan Gazdaga, Eszter Viráge
We present plasmid sequences of 21 multidrug resistant isolates of Enterobacterales belonging to Escherichia coli (n=10), Klebsiella pneumoniae (n=9), Klebsiella oxytoca (n=1), and Citrobacter freundii (n=1). The isolates originated from effluent collected from hospital sewer pipes and from a wastewater treatment plant (WWTP) in a southwestern Hungarian city. Isolation was carried out using eosin methylene blue agar supplemented with ceftriaxone and the isolates were identified with MALDI-TOF MS. Screening for multidrug resistance was conducted by determining susceptibility to four chemical classes namely, beta-lactams, aminoglycoside, fluoroquinolone, and sulfonamide. Plasmid DNA was isolated by alkaline lysis method using the Monarch plasmid DNA miniprep kit from freshly grown pure colonies. Molecular typing and Illumina sequencing of plasmid DNA of multiresistant strains were performed. After the assembly of contigs, genes localized on plasmid sequences were determined and functionally annotated. These reconstructed plasmid sequences supplemented with gene functional annotations were deposited in the Mendeley data. Using these datasets different plasmid incompatibility groups were identified. These conjugative plasmids appear to play a key role in the transmission of multiple resistance genes in enteric bacteria via wastewater. The presented data may provide useful insight on the correlations between environmental antibiotic contamination and the development of bacterial resistance, which poses a serious public health threat.
Occurrence of antibiotics and bacterial resistance genes in wastewater: resistance mechanisms and antimicrobial resistance control approaches
(World Journal of Microbiology and Biotechnology, 2022-07-04) Mutuku, Christopher, Zoltan Gazdag, Szilvia Melegh
Antimicrobial pharmaceuticals are classifed as emergent micropollutants of concern, implying that even at low concentrations, long-term exposure to the environment can have signifcant eco-toxicological efects. There is a lack of a standardized regulatory framework governing the permissible antibiotic content for monitoring environmental water quality standards. Therefore, indiscriminate discharge of antimicrobials at potentially active concentrations into urban wastewater treatment facilities is rampant. Antimicrobials may exert selective pressure on bacteria, leading to resistance development and eventual health consequences. The emergence of clinically important multiple antibiotic-resistant bacteria in untreated hospital efuents and wastewater treatment plants (WWTPs) has been linked to the continuous exposure of bacteria to antimicrobials. The levels of environmental exposure to antibiotics and their correlation to the evolution and spread of resistant bacteria need to be elucidated to help in the formulation of mitigation measures. This review explores frequently detected antimicrobials in wastewater and gives a comprehensive coverage of bacterial resistance mechanisms to diferent antibiotic classes through the expression of a wide variety of antibiotic resistance genes either inherent and/or exchanged among bacteria or acquired from the reservoir of antibiotic resistance genes (ARGs) in wastewater systems. To complement the removal of antibiotics and ARGs from WWTPs, upscaling the implementation of prospective interventions such as vaccines, phage therapy, and natural compounds as alternatives to widespread antibiotic use provides a multifaceted approach to minimize the spread of antimicrobial resistance.
consumer behaviour among domestic tourists: a case study of travel agencies in Nairobi, Kenya
(chuka university, 2024-06-26) Kambaga Dunstan1 , Mongare Omare2 , Lawrence Muriuki
The Consumer Behaviors is a combination of acts, attitudes and decisions made concerning the buying and consuming of the tourism products and services offered to tourists in destination areas and its postbuying reactions. Consumer behavior plays a key role in marketing activities of tourist products especially in promoting and selling tourism products and services in tourist destinations. The purpose of this research study is to establish factors affecting consumer behavior among Domestic tourists in travel agents in Nairobi, Kenya. The specific objectives of the study were to determine the extent to which price, product and safety affects consumer behavior among Domestic tourists in travelling agents. The research adopted descriptive design. The target population was 306 (KATA,2019) employees involved in travelling agents and sample size of 75 employees were selected using Fisher, Laing & Stoeckel (1983) formula. The study used both systematic techniques and stratification methods from each stratum in sampling employees. Convenient method was used to select 35 travel agents out of 114 (KATA, 2019) in Nairobi (Appendix II). The study used both primary and secondary data which was collected by use of questionnaire survey. The analyzing of qualitative data was done by use of the format in the thematic content analysis, while, quantitative data was done by use of descriptive and inferential statistics through the use of statistical packages for social sciences (SPSS), Chi-square (χ2 ), ANOVA and descriptive tests were performed. The data were presented by use of graphs, pie charts and table. Employees were asked to respond to a set of statements on the Likert scale where 5=strongly agreed, 4= agreed 3= neutral, 2= disagree, 1= strongly disagree and they had enough knowledge about travel agents in order to understand and respond to the questions. Descriptive analysis was used to summarize data regarding product, price and safety and Consumer Behavior in tourism destination. It’s evident that majority of the respondents strongly agreed that product, price and safety influence a tourist in decision-making to consume a product. Correlation analysis was used to investigate the existence and nature of relationship between Product, Pricing, Safety and consumer behavior among Domestic tourists. The study concludes that tourist behaviors is strongly influenced by price with 41.4% change followed by product and safety respectively as indicated by a Pearson correlation coefficient of .653**,.611** and .633** These relationships were found to be statistically significant as the significant value was 0.000 which is less than 0.05 threshold. Since, price, product and safety affects tourists, further research for Safety should be carried on to ascertain the individual safety of tourists in destination areas, especially this era of Al-Shabaab which is a security challenge to Kenya and the horn of East Africa as a whole. The study will benefit travel agents and tourism industry as a whole since the sector continues to be one of the largest industries in the world. Also, further research with wider scope to be carried on as this study could not exhaust all the factors affecting consumer behavior among Domestic tourists.
Assessment of Heavy Metals Contaminants in Nkenye Stream in Meru South, Kenya
(Journal of Environmental Sustainability Advancement Research, 2022) Kithaka, S. C.; Njagi, E. C.; Njagi J.
Access to portable water remains a major global concern due to its dimishing supply and increasing and competiting demand. Water scarcity is aggrevated by the increasing pollution from different sources. Nkenye stream in Meru South is depended upon source of water for domestic, agriculture and agricultural processing, Nonetheless, little attention has been accorded to ascertain the quality of its water despite of the stream being located in an urban area with high exposure to pollutants. Pressure on Nkenye wetlands ecosystem that habour Nkenye stream has seen major destruction of riparian leaving just few plant communities such as Commelina banghalensis whose water purification potential is not well known. A study was conducted to determine water quality of Nkenye stream. Samples were collected at designated locations using ecological survey method and taken to Chuka University for analysis. Macrophyte roots were cleaned and dried then powdered and digested using nitric acid. Sediment samples were dried, ground to pass a 2 mm non-metal sieve.The digested samples were diluted and analyzed using atomic absorption spectrometry model PG990 at Chuka University. The concentration of anions was determined by ion chromatography at Chuka University Chemistry laboratory. The results obtained from the field and laboratory were analyzed by General linear model (GLM) on Statistical analysis system (SAS) version 9.4 and significance means separated by Least significance difference (LSD) [alpha = 0.05]. The results showed that Nkenye stream is polluted with iron, copper and lead. However, the concentration of iron and copper were within the allowable concentrations for potable water by the World Health Organization while lead was slightly higher by 0.02 ppm. The results obtained were analyzed by General linear model (GLM) on Statistical analysis system (SAS) version 9.4 and significance means separated by Least significance difference (LSD) [alpha = 0.05]. The metals contaminants observed in the Nkenye stream water, sediments and root samples may be associated with discharge of wastes from Chuka town particularly wastes from car wash, garages and from farms that surround the stream and the wetland. Considerable amount of lead, copper and iron was observed in the root samples of Commelina banghalensis. This is an indication that Commelina banghalensisfo can be used can be used for the removal of contaminants from water. Local authorities should provide waste management disposal systems and policies that prohibit direct discharge of untreated effluents into the stream.
Solid Waste Management Practices at Egerton University,Njoro C ampus and the Community Around
(Chuka University, 2018-07-11) Kariuki ,J.M.Soi,B. Mutio, A.N.Kinyanjui,D.N.
The purpose of this study was to characterise existing solid waste management practices in the study area. StudyDesign:Thestudywasacross-sectionalsurvey Place and Duration:It was carried out between January – May 2009 within Egerton University, Njoro campus and the community around it, all within Njoro division. Methodology:Thesamplecomprised220respondentsthatweredrawnfromtenants,farmersand the business community. A semi-structured questionnaire was used to gather quantitative data which was analysed using frequency tables by the Statistical Package for Social Sciencessoftware. Results:The study established that use of open dumpsite as the final disposal option was done within the University as well as for the community around the university. Open dumps and waste pits near living areas were fairly common outside the university but very rare within the University. Whereaswastecollectionwascommonintheuniversity,it wasrareoutsidetheUniversity.Waste burning was fairly common outside the university with more than 70% of the business people and the tenants burning their waste whereas tenants and students within the University never burnttheir waste.Waste minimisation practices like shopping witha durable bag were practiced by over 50%oftherespondents.Wasteseparation,practicedby36%oftherespondentswasnotpracticed for environmental reasons but to extract materials that were still useful. Conclusion:wastemanagementwithintheuniversitywasbetterduetothepresenceof waste collection and centralised disposal which were lacking in the community outside the university
Nile Tilapia (Oreochromis Niloticus Linnaeus, 1758) Culture in Kenya: Emerging Production Technologies and Socio-Economic Impacts On Local Livelihoods
(John Wiley & Sons Ltd, 2022-05-22) Munguti, Jonathan M.; Rita Nairuti Jacob O. Iteba Kevin O. Obiero Domitila Kyule Mary A. Opiyo Jacob Abwao James G. Kirimi Nicholas Outa Mavindu Muthoka Cecilia M Githukia Erick O. Ogello
Nile tilapia (Oreochromis niloticus) is one of the most farmed fish globally, with a significant contribution improving local livelihoods, especially in developing countries. Nile tilapia was first cultured in Kenya in 1924 and is the most cultured fish species. Annually, O. niloticus accounts for 62% (∼15,000 tonnes) of total aquaculture production. Although O. niloticusis the most preferred cultured fish, its culture faces challenges, for example, early maturation due to prolific breeding behaviour leading to stunted growth that limits its culture and profitability among smallholder farmers. With the surging demand for locally farmed fish, innovative technologies have emerged to boost aquaculture production. Donor and public research-funded projects, for instance, the Kenya Climate Smart Agriculture Project, are validating various aquaculture technologies, innovations and management practices (TIMPs) to achieve ‘triple wins’ of increased fish production, improved resilience and reduced greenhouse gas emissions. In addition, the International Fund for Agricultural Development (IFAD)-funded Aquaculture Business Development Programme aims at commercialising aquaculture to improve local livelihoods. In this study, we adopt a scoping review methodology to review and synthesise published literature on tilapia culture in Kenya to explore current and emerging tilapia production technologies and document their socio-economic impacts on farmers’ livelihoods. These emerging innovative technologies range from culture systems, for example, biofloc, periphyton, fingerpond technology, integrated aquaculture, breeding and genetics (selective breeding), fish health and biosecurity measures, to post-harvest loss reduction, value addition and marketing. The study findings reveal that the technologies have great potential to increase tilapia production and profitability and positively impact the local livelihoods of smallholder fish farmers through employment creation, economic growth and better nutrition
Causes of Environmental Degradation in Chuka Igambang`Ombe Sub-County, Kenya
(Journal of Environmental Sciences and Technology, 2024-05-09) Sarah Kagendo Gitonga(1) ; Dickson Nkonge Kagema(2) ; Jonathan Kathenge(3
This study investigated the causes of environmental degradation in Chuka Igambang’ombe Sub-County, Tharaka Nithi County, Kenya. Environmental degradation, characterised by deforestation, pollution, and soil erosion, poses significant threats to ecosystems and human well-being. Environmental challenges persist despite the Catholic Church's active participation in conservation efforts such as tree planting, river rehabilitation, soil conservation, and awareness campaigns. Identifying the underlying factors is crucial for developing effective interventions. The study employed a descriptive survey design targeting a population of 15,574 Church members. A sample size of 389 participants was selected, including ten priests, ten development committee members, 86 youths, 98 members of the Catholic Men Association (CMA), and 175 members of the Catholic Women Association (CWA). Data was collected through interviews and questionnaires and analysed using descriptive statistics. The findings revealed that deforestation, pollution, improper waste disposal, overgrazing, lack of environmental knowledge, and encroachment on natural habitats were crucial factors contributing to environmental degradation in the region. The study concludes that these factors and inadequate management strategies exacerbate degradation. It is recommended that the government and stakeholders enforce stricter regulations against deforestation, promote environmental education, and enhance waste management practices to mitigate these effects
Climate Variability and Its Impacts on Wildlife Ecosystems: A Study of Meru Conservation Area, Kenya
(Journal of Natural Sciences Research, 2018-04-18) Edwin Kiria
Climate variability is currently a major concern not only to conservationist but also to several other disciplines such agriculture and production sectors. The world’s climate continues to change at rates that are projected to be unprecedented in recent human history. Climate change adds to the impact of land use change on species and ecosystems. Rising temperatures, rainfall variability, and new climatic regimes pose threats to biodiversity and human livelihoods alike. A study conducted at Meru Conservation area, Kenya established that that has been a climate variability which has over time affected wildlife populations, wildlife ecosystems and human livelihoods within and around the protected areas. This has however exposed wildlife conservation at a higher risk due to continuous loss of preferred habitats, movement corridors, dispersal areas and population decline.
Climate Variability and Its Impacts on Wildlife Ecosystems: A Study of Meru Conservation Area, Kenya
(Journal of Natural Sciences Research, 2018-03-16) Edwin Kiria
Climate variability is currently a major concern not only to conservationist but also to several other disciplines such agriculture and production sectors. The world’s climate continues to change at rates that are projected to be unprecedented in recent human history. Climate change adds to the impact of land use change on species and ecosystems. Rising temperatures, rainfall variability, and new climatic regimes pose threats to biodiversity and human livelihoods alike. A study conducted at Meru Conservation area, Kenya established that that has been a climate variability which has over time affected wildlife populations, wildlife ecosystems and human livelihoods within and around the protected areas. This has however exposed wildlife conservation at a higher risk due to continuous loss of preferred habitats, movement corridors, dispersal areas and population decline. Keywords: Climate Variability, Wildlife Populations, Wildlife Ecosystems, Human Livelihoods
Spatiotemporal trajectories of invasive tree species reveal theimportance of collective action for successful invasionmanagement
(Informa UK Limited, 2022-10-02) Adoyo, Beatrice; Schaffner, Urs; Mukhovi, Stellah; Kiteme, Boniface; Mbaabu, Purity Rima; Eckert, Sandra; Choge, Simon; Ehrensperger, Albrecht
Biological invasions are complex processes requiring coordinated andspatially targeted management. This study assessed spatiotemporal tra-jectories and determinants of Prosopis cover in Baringo County, Kenya.Land cover data for every seven years between 1988 and 2016 revealedthe presence of Prosopis. We tested for trajectory clusters using spatialautocorrelation and overlaid the trajectory categories with landscapefeatures. Generally, most plots were only temporarily managed or notmanaged at all, while continuous management of Prosopis occurredmainly near rivers and on plots suitable for cultivation. Parcels within250 m from roads, which are dispersal pathways for Prosopis seeds, wererarely cleared of Prosopis. We conclude that successful managementrequires incentives for stakeholders’ engagement in collective manage-ment action at a landscape level. Trajectory mapping should be integratedinto planning tools to foster the prioritization of timely and context-specific response mechanisms.
Impacts of Covid-19 Pandemic and Adaptive Strategies to Build Resilience in the Kenyan Aquaculture Sector
(ScienceOpen, 2022-10-08) Jonathan Munguti, Jacob O. Iteba, Nicholas Outa, James G. Kirimi, Daniel Mungai, Domitila Kyule, Kevin Obiero, Erick O. Ogello
This study examines the impacts of Covid-19 pandemic and adaptive strategies to build resilience among stakeholders and actors in the aquaculture value chain in Kenya. Prior to the pandemic, Kenya's aquaculture sector had progressed from a minor player to a key component of the country's fish food system. Fish and fishery products have become the most heavily traded food commodity in Kenyan markets. The results indicate that the pandemic had major impacts on the access to aquaculture inputs, fish trade, and socio-economic livelihoods of the aquaculture value chain stakeholders and actors during the two whole years. Thus, initial and longer-term adaptive measures, in particular by private sector players and government agencies can contribute to building resilience to multiple shocks and stressors among stakeholders and actors in the aquaculture sector. Some of the measures include government incentive package to overcome the damage to the fisheries and aquaculture sector, improve farming operations and win market trusts and adoption of new methods such as intelligent sensors, camera systems and automated or remotely controlled monitoring/feeding strategies to reduce labour intensity. Such measures and policies can cushion the sector against future shocks occasioned by such pandemics.
Influence of variation in biophysical factors on tree species structure and composition in Kapseret forest, Uasin Gishu county, Kenya
(Journal of Environmental Sustainability Advancement Research, 2022) Kutuny, G. K.; Njeru, J. R.; Mutuma, E.
Forests are important for survival and development of human and other fauna. However, they are under degradation due to changes in biophysical factors which affects tree species structure and composition. Understanding these variations and their influence on tree species structure and composition guides conservation of forest. This study aimed at assessing the influence of variation in biophysical factors on tree species structure and composition. Ecological survey was used whereby, tree species and soil samples were studied from 12 sample plots identified through stratified sampling techniques within Kapseret forest. Tree species were enumerated and recorded by species name and Diameter at Breast Height (DBH), those with ≥3m height and DBH > 9.5 cm were classified as trees, while those with ≤3m height and less than DBH ≤ 9.5cm were recorded as saplings. Tree species attributes assessed included: tree DBH and diversity, while biophysical variables measured were: soil organic carbon (SOC), soil texture, phosphorous and potassium. A total of 148 tree species were identified with 62.16% being saplings while 35.14% were mature trees. The CCA results indicated positive correlation between tree species diversity with variation in biophysical factors, the presence of gaps with high P levels were associated with majority of the saplings, however, the DBH class distribution did not indicate an inverse J-shape portraying high degradation. The tree species-biophysical factors should therefore be utilized with other environmental factors such as topography,light intensity,temperature and wind when planning and choosing species for rehabilitation and restoration of degraded landscapes.
Effects of Potassium Application on Yield, Protein and Oil Content of Selected Soybean Varieties in Trans Nzoia County, Kenya
(Research International, 2023-06-12) Kimkung Sam Kibet a*, Gathungu Geofrey Kingori a and Muraya Moses Mahugu
seed weight, grain yield, protein and oil content. Data collected was subjected to analysis of variance using Statistical Analysis System version 9.3 and significantly different means separated using Least Significance Difference at α = 0.05. Application of potassium at the rate of 67.5 kg K2O ha-1 resulted to higher number of pods per plant and number of seeds per plant at 78.97 and 243.40, and 44.47 and 141.20 in the varieties DPSB19 and Gazelle, while in SB24 higher recording of 51.23 and 162.40 was observed with 22.5 kg K2O ha-1 . The higher 1000-seed weight was recorded in 22.5 kg K2O ha-1 in DPSB19 and Gazelle varieties, while for SB24 it was recorded in 67.5 kg K2O ha-1 . The highest grain yield recorded was 9156.45 kg per ha, in DPSB19 in 22.5 kg K2O ha-1 , 4517. 67.5 kg per ha in Gazelle variety in 67.5 kg K2O ha-1 and 6432.78 kg per ha in SB24 variety in 22.5 kg K2O ha-1 . The higher percentage oil content was observed in 45 K2O kg ha1 in DPSB19 (28.48%) and SB24 (23.38%) varieties, and in 22.5 kg K2O ha-1 in Gazelle (19.38%) variety and the higher percentage protein content was recorded in 45 K2O kg ha-1 in DPSB19 (42.99%) and Gazelle (40.56%), and in 45 K2O kg ha-1 in SB24 (48.87%). These findings show that soybean farmers should apply potassium fertilizer for appropriate growth, increased yield, protein and oil content in different soybean varieties. It is recommended that application of potassium at 67.5 kg K2O ha-1 be done for better soybean growth, yield and protein content and application of potassium at 45 kg K2O ha-1 is done for high oil content.
Assessment of benthic macroinvertebrates as bio indicators of water quality in river Naka, Chuka, Tharaka-Nithi, Kenya
(Journal of Environmental Sustainability Advancement Research, 2022) Chamia, L. K.; Kutuny, G. K.
Freshwater ecosystems worldwide have been progressively deteriorating leading to a decrease in aquatic biodiversity. Conventionally, evaluation of water quality uses single physical-chemical parameters which may be insufficient to fully assess the quality of freshwaters. This study used bio-indicators to assess water quality of River Naka in Tharaka-Nithi County, Kenya. Fluvial ecosystems support rich and diverse assemblages, making them vulnerable to possible alterations in the habitat. The study assessed the diversity and abundance of benthic macroinvertebrate communities and their use as bioindicators of water quality. Grab sampling was used to collect water samples, a kick sampler and D-frame aquatic net was used to collect 121 benthic macroinvertebrates from three selected sites and determined using EPT Index (Ephemeroptera, Plecoptera and Trichoptera group). The data obtained was used to determine the index of the sampling sites. Physico-chemical factors were analyzed in-situ (temperature, turbidity and pH) and in the laboratory(nitrates and phosphates). The highest EPT index values (28) at the upstream corresponded to good water quality, while the slightly low values (21) at the midstream indicated moderate water quality and the lowest values (15) recorded at the downstream showed fair water quality. The downstream water quality parameters exceeded World Health Organization limits, posing a health risk to water consumers. Continuous bio-assessment of rivers based on EPT biotic indicators should be conducted on a regular basis to establish a long-term profile of water quality state and ecological integrity of rivers.
Variation in Temperature and Nutrient Source Influence the Growth of Exserohilum Turcicum Mycelia Isolated from Sorghum
(Journal of Scientific and Engineering Research, 2019) O. Ogolla, Fredrick; M. Muraya, Moses; O. Onyango, Benson
Turcicum leaf blight (TLB) caused by the fungus Exserohilum turcicum is a serious threat to production of maize and sorghum, since it damages photosynthetic leaves. Growth and development of E. turcicum pathogen is influenced by factors such as light, temperature, dew period, plant age and inoculums concentration. Tharaka Nithi county in Eastern Kenya where sorghum is actively grown has heterogenous climatic and edaphic conditions. It is currently unclear if variations in temperature and media type may influence growth, development and virulence of Exserohilum turcicum. Thus, this study was carried out to investigate the effect of media type and different temperature variations on the growth and development of mycelia of E. turcicum isolates from Tharaka Nithi county in Kenya. Results showed that the effect of temperature was significantly differences for development of E. turcicum (Pr < 0.05) mycelia. Media type had significant effect on growth of E. turcicum isolates (p<0.05). Corn meal agar with mean of 4.233 cm was the best growth media followed by Malt extract agar at 3.3200 cm, while the most preferential (p<0.05) temperature for mycelia growth was 30 oC. The study recommends in cooperation of wider environmental factors in future studies involving TLB pathogen from Tharaka Nithi county.
Assessment of Rhizobia Strains Isolates of Soils around Lake Victoria Basin for their Effectiveness in Nodulation and Symbiotic Efficiency on Soybeans and Bambara Groundnuts
(International Journal of Environment, Agriculture and Biotechnology (IJEAB), 2019-10) Onyango O. Benson; Ogolla O. Fredrick
The symbiotic Biological nitrogen fixation (SBNF) is a sustainable and low-cost alternative to expensive and inaccessible inorganic fertilizers. However, SBNF is underutilized in soils of Lake Victoria basin due to insufficient information on local rhizobial strains diversity and their N-fixation efficiency. This study was carried out to assess the effectiveness of rhizobium strains isolates of Kisumu, Port Victoria, Kendu bay and Karungu soils within Lake Victoria basin in nodulation and symbiotic efficiency on soybeans and bambara groundnuts. Two bambara seeds of groundnut landraces; Kakamega Cream (KAKC) and Busia Brown (BUSB) used in this study were collected from farmers in Kakamega and Busia counties respectively. Screen house experiment was performed at Kenya Forestry Research (KEFRI) in plastic pots with four seeds of each cultivar which was later thinned to two plants. Randomized Complete Block Design (RCBD) was used. Experiments data were subjected to analysis of variance (ANOVA) using Genstat 16th Edition and significant means separated using Least Significant Difference at [LSD5%] and Dancun Multiple Range Test (DMRT). Result indicated highly significant (p<0.05) effect of isolate inoculation on number of nodules per plant. Soybean Variety SB19 formed effective nodules with rhizobia in the genera Bradyrhizobium, Rhizobium and Agrobacterium. On the other hand, ‘Safari’ was quite selective and formed very few nodules with isolates identified as Bradyrhizobium. However, both varieties SB19 and ‘Safari’ had better growth under glasshouse inoculation with Bradyrhizobium spp., rhizobia isolates although one Rhizobium isolate (SoyKis1) resulted in good nodulation of both varieties. Seed treatment of the two legumes with some isolates resulted in improved nodulation and better plant growth; in some instances, outperforming the commercial strain Bradyrhizobium japonicum USDA110. In conclusion, Isolates BAMKis12, BAMKis8, BAMKis4, BAMKbay8 and SoyKar2 were found to be potential elite strains and are recommended for more host range tests as viable inoculants sources.

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