School of Agriculture, Environment, Water and Natural Resources Managementhttp://repository.seku.ac.ke/xmlui/handle/123456789/862024-03-28T17:48:25Z2024-03-28T17:48:25ZEnvironmental and socio-economic predictors of anthrax spatial distribution in KenyaOtieno, Fredrick T.http://repository.seku.ac.ke/xmlui/handle/123456789/73572023-12-01T07:17:24Z2023-10-19T00:00:00ZEnvironmental and socio-economic predictors of anthrax spatial distribution in Kenya
Otieno, Fredrick T.
Anthrax spatial distributions and the potential driving factors remain poorly understood
worldwide and in Kenya. This study aimed at establishing environmental and social economic predictors of the spatial distribution of anthrax in Kenya through (1)
determining the relationship between selected environmental and socio-economic
factors on spatial distribution of anthrax through use of an ecological niche modelling
framework; (2) predicting the effect of climate change on the future spatial distribution
of anthrax; and (3) establishing the influence of socio-economic factors in vulnerability
to anthrax. Ecological Niche Model (ENM) of boosted regression trees (BRT)
algorithm was applied to predict the suitable spatial environments for anthrax under
current and future climate scenarios in Kenya. The model fitted confirmed anthrax
occurrences from three distinct sources of retrospective records (2011 to 2017),
sporadic anthrax outbreaks (2017 to 2018) and active surveillance (2019 to 2020)
against selected predictor variables to yield current and future anthrax risk maps.
Finally, the underlying socio-economic vulnerability due to the risks of anthrax
distribution was assessed by laying over socio-economic indicators in spatial
multicriteria decision analysis to produce socio-economic vulnerability maps. The
high-risk areas for anthrax outbreaks were identified predominantly in: regions around
western Kenya bordering Uganda; southwestern regions bordering Tanzania and
regions around central highlands of Kenya. Based on the current scenario, the number
of humans affected was estimated at ~ 193,00,840 people/sq.km while that of livestock
was at ~7,750,675 animals / sq.km. The important contributing predictor variables were
predominantly cattle density, rain of the wettest month, monthly precipitations, soil
clay, soil pH, soil carbon, longest dry season and temperature range. The anthrax highly
suitable areas expanded from current to future climatic scenarios with current at 36131
km2, RCP 4.5, 40012 km2, and RCP 8.5, 39835 km2. Highly socio-economic
vulnerable areas closely correlated with areas of high anthrax risk currently and into the
future. At current vulnerability index > 75%, approximately 40,369,455 people were
estimated to be at risk. This study results will guide risk-based surveillance and
strategies for managing anthrax under One Health approach and also contributes to
future research studies within Kenya and beyond.
Doctor of Philosophy in Environmental Management, 2022
2023-10-19T00:00:00ZThe impacts of agricultural sector devolution on delivery of agricultural extension services and agricultural productivity in Kitui County, KenyaKyambo, Onesmus M.http://repository.seku.ac.ke/xmlui/handle/123456789/73542023-12-01T07:29:06Z2023-10-19T00:00:00ZThe impacts of agricultural sector devolution on delivery of agricultural extension services and agricultural productivity in Kitui County, Kenya
Kyambo, Onesmus M.
Agriculture supports the livelihoods of rural people in developing countries, including
Kenya. Agriculture is the mainstay and driver of the Kenyan rural economy. Despite the
critical role of agriculture in Kenya, poor access to extension support services persists.
The study was carried out to evaluate the impact of devolution of the agricultural sector
on the provision of agricultural extension services and agricultural productivity in Kitui
County. To achieve this objective, the following specific objectives were addressed,
namely to: assess the influence of selected socio-economic factors on farmers’ awareness
of the devolution of agricultural extension services; determine the factors influencing the
delivery of extension services by the county governments; establish the interactions
between agricultural extension functions run by county and national governments; and
assess the impact of agricultural extension services on the farmers’ household income
with respect to agricultural productivity and income as proxies for the years 2012 (before
devolution) and 2016/2017 (after devolution). A total of 70 extension officers and 99
farmers were sampled from Kitui County using a stratified random sampling approach.
Secondary information sources such as national and county ministries’ reports and
existing literature were reviewed to supplement the primary data. A questionnaire was the
main tool used for data collection in this study. Data obtained were analyzed through:
descriptive and inferential statistics; binary logistic regression; linear regression; and
stochastic frontier analysis. The logit binary model showed that age of household, gender,
education, income, and size of the land were important factors that influenced farmers’
awareness of the devolution of agricultural extension services. Further, this study
established that most of the sampled respondents reported insufficient performance in
extension service provision by the county government due to challenges such as
inadequate transport, salaries not paid on time, lack of proper staff promotion, lack of
clear terms of service without duplication, unconducive work environment, and low
facilitation for extension activities. There is minimal interaction between agricultural
extension functions run by county and national governments due to the minimal
involvement of county extension staff in the development and implementation of the
work plans as well as monitoring and supervision at the national level. For example, the
sampled smallholder maize farmers who had access to agricultural extension services had
their yield productivity increase by 16.4%. The devolution of agricultural extension
services resulted in a significant improvement in agricultural productivity and farmer’s
income by 27.2% and 13.8%, respectively. This study recommends that more campaigns
with focus on women's groups and elderly farmers should be held in the vast Kitui
County to create awareness about the devolution of agricultural extension services.
Greater involvement of extension staff in development and implementation of work plan
at the national level as well as monitoring/supervision should be enhanced in order to
contribute to better interactions between national government and county governments.
Also, there is a need to provide incentives to extension officers through adequate
facilitation, remuneration, and promotion. Therefore, adequate funds should be allocated
to the devolved agricultural extension services, for example, a specified percentage of the
agriculture sector budget as a way of enhancing overall agricultural productivity and
households’ incomes.
Doctor of Philosophy in Agricultural Economics, 2022
2023-10-19T00:00:00ZPhenological characteristics, wool yield and quality of three selected provenances of Calotropis procera (Ait) in the South Eastern drylands of KenyaMutiso, Festus M.http://repository.seku.ac.ke/xmlui/handle/123456789/73372023-12-01T07:55:42Z2023-10-18T00:00:00ZPhenological characteristics, wool yield and quality of three selected provenances of Calotropis procera (Ait) in the South Eastern drylands of Kenya
Mutiso, Festus M.
Calotropis procera is a dryland species which produces wool. In order to domesticate the species for wool production, a study was undertaken to evaluate growth, phenology and wool productivity of selected provenances of C. procera in the drylands of South Eastern Kenya. The research site was located at South Eastern Kenya University (SEKU) off Kwa Vonza, Kitui County, Kenya. Geographically, it lies at 01.313580S, 037.755460E & 01.314220S, 037.755760E at an elevation of 1173m above sea level (a.s.l.). The objectives of the study were to: i) determine the germination and early growth of three C. procera provenances in three soil types under nursery conditions, ii) to determine growth and phenological characteristics of three provenances under field conditions and at different spacing, iii) to quantify seasonal wool yield and quality from three provenances and iv) determine soil chemical characterization of the study site. The experiments were done at nursery and field levels. The experiments were done at nursery and field levels. The nursery and field experiments were laid out in a randomized complete block design and replicated three times. The nursery media treatments were three provenances and three soil media while field treatments were three provenances and three spacing levels. At the nursery, data on germination energy, energy period, germination rate, germination value and seedlings mortality were collected. Field data included growth data, phenological data, soil data and plant tissue data. Charts were generated to depict germination attributes. Computations of germination values were done using Czabator and Djavanshir and Pourbeik methods. Correlation analysis of germination attributes were also done. Seedling leaf production and height data were subjected to analysis of variance (ANOVA) and means separated using Tukey’s test (post hoc, p < 0.05). The field data was subjected to ANOVA to detect significant statistical differences (p < 0.05). Wool quantification and wool quality analysis were done in the laboratory. ANOVA was applied to assess the significance of variations in the soil chemical properties, plant tissue data, C. procera provenances and spacing variables in relation to the field plots. Tharaka provenance and sand soil had the highest germination energy of 76% and 83%, respectively, and a similarly high germination value of 87.67% and 86.21%, respectively. Analysis of Variances for branching indicated significant differences (p<0.05) with Baringo provenance recording a p-value of 0.043, Kibwezi, 0.01 and Tharaka, 0.0001. Dancun Multiple Range Test (DMRT) showed no significant differences in diameter growth for all the three provenances though height growth was significant (p < 0.05). All the three provenances showed strong and positive correlations (Pearson, p <0.01) for branching, DBH and height with Baringo recording rs=0.975, Kibwezi (rs=0.988) and Tharaka (rs=0.996). Flowering was characterized by clear-cut phenophases. Spearman rank correlations between wet seasons and flowering ranged from 0.89-0.96 and were highly significant. Growth, flowering and fruiting was impeded by periodic attack by Aphis nerii. 1.5*1.5m spacing level had highest wool production per Ha, followed by 2*2m then 3*3m, while 3*3m spacing gave the highest amount of wool per plant. Despite the fact that C. procera wool quality compared relatively well with that of cotton, spinning of the wool presented a challenge. There were no significant differences in subplots soil chemical properties. The study concluded that C. procera can be grown as a plantation crop with 1.5*1.5m spacing being the most appropriate from the economic perspective. Attack of C. procera by Aphis nerii is a major challenge in adopting the species as a plantation crop while failure of the fibres to separate during spinning presents a challenge in large scale use of the wool in textile industry. The study strongly recommends use of normal nursery soil (forest soil) due to its ability to promote early growth. Further, seeds for raising plantation stock should be obtained from the nearest source to reduce effects of seed transfer distance. Further research on improvement of the spinning properties of the wool is strongly recommended.
Doctor of Philosophy in Environmental Management, 2021
2023-10-18T00:00:00ZInfluence of tea, forest and mixed farming land uses on stream flow and sediment flux in Sondu Miriu river basinKoech, Nancy C.http://repository.seku.ac.ke/xmlui/handle/123456789/72542023-11-30T10:00:35Z2023-06-20T00:00:00ZInfluence of tea, forest and mixed farming land uses on stream flow and sediment flux in Sondu Miriu river basin
Koech, Nancy C.
The changing patterns of land cover and land use in the tropical river basins over time are critical. However, there is limited data and information on the extent to which land use types in tropical regions affect hydrological processes particularly in terms of stream flow and sediment transport. The magnitude to which stream flows and sediment flux differ in tea plantations, forests and mixed farming land covers has not been determined adequately in tropical river basins. The main goal of this study was therefore to determine the influences of different land covers tea plantations, forests and mixed farming on magnitudes of stream flow and sediment flux variability. The study was undertaken in three sub basins namely Timbilil sub basin dominated by tea plantations, Kiptiget sub basin dominated by forests and Kipsonoi sub basin dominated by mixed farming at the upstream of Sondu Miriu River Basin located in the Western Kenya region in period from 1960-2021. Field-based investigations was done using a depth integrated sampler to collect samples for Total Suspended Sediments Concentrations (TSSC), Acoustic Doppler Current meter and Seba current meter were used to measure flow velocities and river gauges were used to measure water levels in the sub basins. Turbidimeter was used to determine turbidity levels in the rivers draining the sub basins. Laboratory analysis and hydrological modelling were used to determine response of hydrological components in dominant land cover types. Spatial data used were obtained from the USGS and FAO databases, while temporal data used were obtained from Kenya Meteorological Services (KMS), Water Resources Authority (WRA) and Ministry of Water, Sanitation and Irrigation. Regression and correlation techniques were used to determine relationship between stream flows and sediment yields. Scenario analysis was carried out to test the effectiveness of various catchment management structures in the sub basins with high sediment generation. The findings of this study showed that the forest land cover in the sub basins dominated by tea plantation and mixed farming land covers declined by 8.4% (4 km2) and 0.3% (26 km2) respectively in the period from 1975 to 2021. Tea plantations land cover showed an increasing trend in all the three sub basins under study from 1975 to 2021. In the sub basin dominated by tea plantation an increase of 7% (24 km2) was observed while in the sub basins dominated by forest and mixed farming land cover, tea plantation increased by 15.2% (23.1 km2) and 6.4 % (101 km2) respectively. The mixed farming land cover portrayed a decline in the sub basins dominated by mixed farming and forest land covers by 6.1 % (96 km2) and 15.4% (23.4 km2) respectively. At the basin scale it was revealed that forest and mixed farming land cover reduced by approximately 16.9% (84 km2) and 3.6% (93 km2) from 1975 to 2021. While the area under tea plantations in the river basin increased by 44% (177 km2) in the same period. It was observed that the sub basin dominated by mixed farming generates high surface runoffs with average of about 30 m3/s compared to average surface runoffs of approximately 4 m3/s generated by sub basins dominated by forest and tea plantation. The sub basin dominated by mixed farming land cover exhibit high turbidity and TSSC levels of about 620 NTU and 630 mg/l in wet seasons. The relationship between TSSC and turbidity in sub basin dominated by mixed farming was positive with coefficient of determination R2 of 0.97. While low levels of turbidity and TSSC of less than 30 NTU and 20 mg/l were observed in the sub basins dominated by forest and tea plantations land cover in wet periods. The sediment loads in the sub basin dominated by mixed farming land cover in the pre planting period were about 900 tonnes/day. The sub basin dominated by the forest and tea plantations land covers exhibited relatively lower sediment generation ranging between 2 and 7 tonnes/day. The sediment loads at the downstream of the river basin ranged from 150 to 600 tonnes/day during the pre-planting and post harvesting periods. The SWAT model simulated the stream flows and sediment yields in the three sub-basins with dominant land covers quite effectively with R2 of 0.8 and Nash–Sutcliff Efficiency (NSE) of 0.78. The SWAT model showed that the mean annual sediment yield in the larger Sondu Miriu River Basin was about 140 tonnes/ha. The identified hotspots’ areas of the sediment generation in the river basin were Kuresoi at the upstream, Ndanai at the middle part and near Sondu market at the downstream. The mean annual evaporation and transpiration was high in the sub basins dominated by tea plantations and forest land covers ranged between 800 mm/a and 1000 mm/a compared to the sub basin dominated by mixed farming land cover with less than 800 mm/a. The relationship between sediment yields and stream flows in the sub basin dominated by forest and tea plantations land covers was weak with R2 of less than 0.24. Whereas a strong relationship between sediment yields and stream flows with R2 of 0.84 was observed in the sub basin dominated by mixed farming land cover. Forest and tea plantations land covers were found suitable for sustainable stream flows and sediment reduction. Also, the terraces, strip cropping and vegetative filter strips were found ideal structures for conserving soils in the sub basin dominated by mixed farming especially the hotspot areas. This study therefore recommends integration of tea plantations and forest land covers to be practiced in the sub basins of the Sondu Miriu River Basin. However, mixed farming should not be replaced completely because it will affect food security in the river basin. Alternatively appropriate soil water conservation measures terracing and strip cropping are recommended to be adopted in mixed farming land uses. This study creates awareness to basin communities, water users and water managers in both County and National Governments on the appropriate land cover and land use that will ensure sustainable availability of water with high water clarity.
Doctor of Philosophy (PhD) in Integrated Water Resources Management, 2023
2023-06-20T00:00:00Z