Master Theses: Department of Water and Agricultural Resource Management
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Item Adoption of Selected Climate Smart Agriculture Technologies among Smallholder Farmers in Lower Eastern Kenya(University of Embu, 2021-09) Muriithi, Lydia NyawiraClimate change has greatly affected food production and food security. Erratic temperature rises and inconsistent precipitation have greatly influenced productivity of crops and livestock. The impacts have gotten much more pronounced among small scale farmers in Kenya whose farming activities are climate reliant. As a component of climate change adaptation, selecting suitable climate smart agriculture (CSA) technologies that can alleviate these adverse consequences is critical. The study sought to determine the factors affecting adoption of selected climate smart agriculture technologies among smallholder farmers in Lower Eastern Kenya, comprising of Machakos, Kitui and Makueni Counties. A sample of 384 households was obtained using multi-stage sampling procedure. A semi-structured questionnaire designed in an open data kit (ODK) application was used to collect primary data from the sampled smallholder farmers. The main adaptation technologies considered were mixed farming, intercropping, crop rotation, conservation agriculture, agroforestry, crop diversification and water harvesting, in that order. Descriptive statistics (frequency and percentages) were used to analyze socio-economic characteristics. Findings revealed that 54.2% of the respondents were males and 35.7% in their productive years (36-50 years). In addition, the findings revealed that most of the interviewed farmers (97.4%) had observed climate change and the effect on food production. Results of the multinomial regression on socio-economic and climate information pathways revealed a positive impact of gender and education level on uptake of crop rotation (0.7%), agroforestry (0.9%) and crop diversification (0.4%) while reliance on mobile phones (0.9%) and neighbors/friends (0.2%) reduced adoption of water harvesting. Multivariate probit model was employed to analyze socio-economic and institutional factors influencing adoption. The likelihood of adopting mixed farming, intercropping and crop rotation significantly increased (p<0.05) among male-headed households and having adequate access to off-farm income and credit facilities. Further, a Food Consumption Score (FCS) was employed to compare quantity and quality of food consumed among households across the three counties. Kitui County had the highest poor FCS at 80% due to lack of adequate knowledge on proper use of the technology than was the case in Kitui (72.5%) and Makueni (73%) Counties. This study therefore recommends promoting adoption of the disseminated CSA technologies, providing reliable extension services plus accessibility to other essential services, like, fertilizer and seeds markets for realizing increased agricultural production in Lower Eastern Kenya.Item Adsorptive Ability of Banana Stalks Biochar in Greywater Remediation for Reuse: A Case of University of Embu, Kenya(University of Embu, 2020-02) Ndung’u, Paul WaweruThe global demand for fresh water resources has been increasing over the years due to population growth, urbanization, industrialization, climate change and the global warming effect. The available water resources have reduced over time leaving a water demand deficit. Recycling and reuse of greywater has been touted as one of the strategies to augment the existing water resources. This study characterized the greywater from students’ hostels and prepared biochar from banana stalks for use as an adsorbent in greywater remediation. The study found significant differences in greywater quality based on source, day and time of sampling. The biochar produced through pyrolysis at pyrolytic temperatures of 300 °C, 400 °C and 500 °C showed the presence of hydroxyl and carboxyl surface functional groups responsible for adsorption of target contaminants. The biochars achieved varying percentage reduction of the selected parameters with biochar prepared at temperature 500 °C recording a significantly higher (p≤ 0.05) percentage removal of Na+, K+ and COD at 65.43%, 89.36% and 60.60% when compared to 58.30%, 56.96% and 49.51% for biochar 400 °C, and 41.13%, 40.36% and 38.31% for biochar 300 °C, respectively. Biochar produced at temperature 300 °C exhibited a significantly higher (p≤ 0.05) reduction of BOD in the greywater of 71.28% as compared to biochars 400 °C and 500 °C which had 66.64% and 61.92% percentage reduction, respectively. Biochar 500 °C was found most suitable for Na+, K+ an COD reduction while Biochar 300 °C most suited the BOD reduction. The results from this study showed that biochar produced from banana stalks can be used as an adsorbent for greywater remediation and the treated water was suitable for consideration in agricultural reuse under the test conditions.Item Adsorptive Ability of Banana Stalks Biochar in Greywater Remediation for Reuse: A Case of University of Embu, Kenya(University of Embu, 2020-12-11) Ndung'u, PaulThe global demand for fresh water resources has been increasing over the years due to population growth, urbanization, industrialization, climate change and the global warming effect. The available water resources have reduced over time leaving a water demand deficit. Recycling and reuse of greywater has been touted as one of the strategies to augment the existing water resources. This study characterized the greywater from students’ hostels and prepared biochar from banana stalks for use as an adsorbent in greywater remediation. The study found significant differences in greywater quality based on source, day and time of sampling. The biochar produced through pyrolysis at pyrolytic temperatures of 300 °C, 400 °C and 500 °C showed the presence of hydroxyl and carboxyl surface functional groups responsible for adsorption of target contaminants. The biochars achieved varying percentage reduction of the selected parameters with biochar prepared at temperature 500 °C recording a significantly higher (p≤ 0.05) percentage removal of Na + + and COD at 65.43%, 89.36% and 60.60% when compared to 58.30%, 56.96% and 49.51% for biochar 400 , K C, and 41.13%, 40.36% and 38.31% for biochar 300 °C, respectively. Biochar produced at temperature 300 °C exhibited a significantly higher (p≤ 0.05) reduction of BOD in the greywater of 71.28% as compared to biochars 400 °C and 500 °C which had 66.64% and 61.92% percentage reduction, respectively. Biochar 500 °C was found most suitable for Na ° an COD reduction while Biochar 300 °C most suited the BOD reduction. The results from this study showed that biochar produced from banana stalks can be used as an adsorbent for greywater remediation and the treated water was suitable for consideration in agricultural reuse under the test conditions.Item Agro-morphological and nutritional Characterization of horned melon Accessions from selected agro-ecological Zones in kenya(University of Embu, 2020-10-26) Owino, Marline HannyAfrican horned melon (Cucumis metuliferus) is an indigenous crop belonging to the family Cucurbitaceae. The crop has been neglected despite its high potential. Therefore, to conserve the biodiversity of this crop, there is need to promote its domestication and production. However, this can only be realized if its morphology, agronomic and nutritional value is understood. The objective of this study was to determine the agromorphological performance and nutritional composition of horned melon accessions obtained from selected agro-ecological zones in Kenya. The study was conducted at the University of Embu research farm for two cropping seasons; October to January 2018 and March to June 2019. The experiment was laid out in a randomized complete block design with nineteen accessions replicated three times. The accessions were planted in experimental plots measuring 3m x 3m at a spacing of 1m by 1m. Morphological and agronomic characterization was based on modified International Plant Genetic Resource Institute (IPGRI) descriptors for melon. Data was recorded from four plants per plot per replicate. The fruit content of Fe and P were determined using atomic absorption spectrophotometry while Na and K were determined using flame photometry procedure. Vitamin C content was estimated by titrimetric method. Sugar content was determined using a brix refractometer. The qualitative and quantitative data obtained from morphological and agronomic characters were organized in a matrix and subjected to cluster analysis. A dendrogram was then constructed using unweighted pair-group method with arithmetic average. Agronomic and nutritional data was also subjected to analysis of variance using XLSTAT 2019 statistical software and means separated using Students Newmans Keuls test at 95% level of confidence. Significant differences (p<0.05) were observed in all the quantitative traits except the number of branches and main vine length. However, qualitative variations were only observed in fruit shape, rind colour and seed shape. In both seasons, the dendrogram separated into 5 supported clusters with the diversity between classes being 63.82% in the first season and 68.84% in the second season and diversity within classes being 36.18% in the first season and 31.16% in the second season. Accessions from Rongo, Wote, Siakago, Maragua, Oyugis and Meru had the highest fruit number and fruit weight for both season hence they can be more preferred by farmers and consumers. The accessions also varied significantly (p<0.05) in their nutritional composition except the Moisture Content and the Vitamin C. The composition of the mineral contents in the fruits followed the order K > P >Na >Fe .Potassium (K) content ranged from 249.52mg/100g-165.17mg/100g for Kangundo and Embu accessions respectively. Sodium (Na) ranged from 2.27mg/100g- 1.10mg/100g for Mitunguu and Siakago accessions respectively. Phosphorus (P) range was 40.49mg/100g8.76mg/100g for Migori and Machakos accessions respectively. Iron (Fe) ranged from 2.61mg/100g-0.80mg/100g for Kianjokoma and Maragua accessions respectively. The horned melon accessions tested in this study showed a high agro-morphological and nutrition variation. The study recommended the accessions from Kehancha, Embu and Siakago which recorded highest sugar content across seasons to be used by plant breedersto improve on taste which is considered to be bland by some consumers.Item Agro-Morphological and Nutritional Characterization of Horned Melon Accessions from Selected Agro-Ecologicalzones in Kenya(University of Embu, 2020-12)African horned melon (Cucumis metuliferus) is an indigenous crop belonging to the family Cucurbitaceae. The crop has been neglected despite its high potential. Therefore, to conserve the biodiversity of this crop, there is need to promote its domestication and production. However, this can only be realized if its morphology, agronomic and nutritional value is understood. The objective of this study was to determine the agromorphological performance and nutritional composition of horned melon accessions obtained from selected agro-ecological zones in Kenya. The study was conducted at the University of Embu research farm for two cropping seasons; October to January 2018 and March to June 2019. The experiment was laid out in a randomized complete block design with nineteen accessions replicated three times. The accessions were planted in experimental plots measuring 3m x 3m at a spacing of 1m by 1m. Morphological and agronomic characterization was based on modified International Plant Genetic Resource Institute (IPGRI) descriptors for melon. Data was recorded from four plants per plot per replicate. The fruit content of Fe and P were determined using atomic absorption spectrophotometry while Na and K were determined using flame photometry procedure. Vitamin C content was estimated by titrimetric method. Sugar content was determined using a brix refractometer. The qualitative and quantitative data obtained from morphological and agronomic characters were organized in a matrix and subjected to cluster analysis. A dendrogram was then constructed using unweighted pair-group method with arithmetic average. Agronomic and nutritional data was also subjected to analysis of variance using XLSTAT 2019 statistical software and means separated using Students Newmans Keuls test at 95% level of confidence. Significant differences (p<0.05) were observed in all the quantitative traits except the number of branches and main vine length. However, qualitative variations were only observed in fruit shape, rind colour and seed shape. In both seasons, the dendrogram separated into 5 supported clusters with the diversity between classes being 63.82% in the first season and 68.84% in the second season and diversity within classes being 36.18% in the first season and 31.16% in the second season. Accessions from Rongo, Wote, Siakago, Maragua, Oyugis and Meru had the highest fruit number and fruit weight for both season hence they can be more preferred by farmers and consumers. The accessions also varied significantlyItem Application of water quality index to assess water quality in river chania, kiambu county, kenya(UoEm, 2020-10-15) Kasyoka, GeofreyHuman-related activities are known to have deleterious effects on the water quality of aquatic ecosystems globally. However, there is limited information on the impact of similar perturbations in tropical regions, especially the River Chania in Kiambu County, Kenya, which is an important source of water for humans and animals and also provides habitat for a variety of flora and fauna along its length. The aim of this study was to determine the spatial and temporal variations of selected water quality parameters in seven sampling sites along a section of River Chania, to evaluate water quality of the river using Water Quality Index (WQI) and to assess the effect of socio-economic factors on water quality of the river. The study used a longitudinal study design in water sample collection. The sample collection was done between October 2018 and February 2019 to cater to the dry and wet seasons. A paired t-test (p< 0.05) was used to compare the water quality variables collected in both the wet and dry seasons across sites to see if these differed longitudinally down the river. The data were subjected to analysis of variance (ANOVA) using Statistical Analysis Software (SAS) version 9.2 and means separated using LSD at p< 0.05 confidence level. The mean values of the physico-chemical parameters were compared with the World Health Organization (WHO) water quality guidelines. The parameters used to compute WQI were nitrates, Total Dissolved Solids (TDS), potassium, sulphates, chlorides, copper, manganese, pH and total phosphates. The study revealed a decline in water quality from the most upstream site (Site 1) from excellent (WQI=23.17) to poor (WQI=>50) and very poor (WQI=>76) water quality at the two downstream sites during the wet season. On the other hand, the socio-economic factors were assessed using a survey employing cross-sectional survey design. The study observed that the education level of the respondents was a positive and significant predictor of the ability of an individual to identify water quality changes in River Chania in the last 10 years with an associated significance of 0.014. Age, household size, change in household number, gender and household income had no significant correlation with the identification of water quality changes in River Chania in the last 10 years. The study recommends that the riparian zone of River Chania, especially at downstream sites, should be protected from interference by human activities (e.g., deforestation, farming) and human interactions with the river ecosystem should be regulated for sustainable utilization, hence protect the water quality from further deterioration. Further research can be conducted to develop models for predicting water quality of the river over time.Item Assessment of fodder conservation in smallholder dairy farming systems in highland and midlands of eastern Kenya(UoEm, 2025-06-03) Kogo, Thomas KipchogeGENERAL ABSTRACT The dairy industry is important for its contribution to the living standard of people, industries, foreign exchange and 4% of the total GDP in Kenya. Productivity of 7.8 liters/cow/day is low and attributed to poor feeding and contribution to high emission of greenhouse gases (GHGs). Fodder scarcity poses a challenge to the achievement of high productivity, while mitigation of fodder scarcity through fodder conservation remains low. Despite common challenges, farms perform differently, in different farm locations with some farms, also called positive deviants (PDs) conserving adequate fodder. In the highlands and midlands of eastern Kenya, information on fodder conservation among smallholder dairy farming systems is limited. The adoption levels and the intensity of fodder conservation technologies including silage and hay, factors affecting the adoption and use of such technologies in (peri-) urban locations and strategies used by PDs in fodder conservation are unknown. Therefore, the study sought to assess fodder conservation technologies among smallholder dairy farming systems in the highlands and midlands of Tharaka-Nithi County, Kenya. Specifically: to determine factors affecting the adoption intensity of fodder conservation. To determine factors of fodder conservation technologies adoption in urban and peri-urban areas. To determine strategies that distinguish PDs from peers (non-PDs) in fodder conservation. A cross-sectional survey was conducted on smallholder dairy farms producing and conserving fodder in Tharaka Nithi County. Multistage sampling procedures were used: purposive sampling of the Sub- counties and locations, random selection of villages and proportional selection of 242 farms through snowball chain referral. The questionnaire was used to collect information, which included: household socio-demographics, husbandry practices, farm characteristics and fodder conservation characteristics. Two towns were chosen purposively to represent urban locations i.e. Chuka (UL, n=68) and peri-urban locations Chogoria (PUL, n=93) in Chuka and Maara Sub-Counties respectively (Total n=161), due to the relatively high number of urban dwellers. Additionally, the PDs (n=24) conserved fodder adequate to last the dry season and had a milk yield of ≥15 kg/cow/day. While non-PDs (n=97) do not qualify for both criterion as farms qualifying for one criteria were discarded. Multiple regression analysis was applied to explain the quantity of fodder conserved. The Multivariate Regression (MVR) model was used to identify and estimate simultaneously the determinants of fodder conservation technologies adoption. Logit regression was used to examine variables that influence the probability of PDs. The study found that most farms were headed by older males who had basic education. Fodder was scarce during the dry season in most farms. Fodder conserved included; silage was conserved in the least number of farms only 26%, but the highest in the quantity of fodder conserved (13 tons); hay was conserved in 40% of the farms, but the quantity conserved was the least (2 tons); crop residue storage was the major conserved fodder by 85% of the farms and the quantity conserved was 5 tons. Quantities of fodder conserved were affected by land size, herd size, duration planned to use conserved fodder, main fodder source during scarcity and the fodder conservation technologies used (silage and hay). Quantities of silage and hay conserved were higher in urban location (UL) than in peri- urban locations (PUL) farms. Crop residue storage was conserved more in non-PD farms, especially in PUL farms. Fodder conserved in UL and PUL was influenced by farm location, land size, herd size, total milk yield per farm, sex, source of fodder during feed scarcity, extension services, period the current stock is expected to last, use of concentrate feeds and breed kept. Access to extension services, milk yield, land size, land under xivfodder, period to use conserved fodder, total herd size, and different combinations of fodder conservation technologies differ between PDs and non-PDs. PDs in fodder conservation are favored by a high level of education, access to extension services, large land, herd size and high milk yield. The study shows knowledge production resources and technology used as important in fodder conservation. Recommended mitigation measures target more education on fodder conservation technologies as well as increasing the adoption of improved fodder production. Knowledge advancement of farmers and policymakers through education and extension increases milk production. Therefore, policymakers can focus on creating enabling policies that promote the adoption of improved technologies as used by PDs to support fodder production and conservation to improve productivity and inform the direction of future research.Item Characterisation of smallholder farming systems and greenhouse gas emissions simulation from maize cropping system in tharaka-nithi county, kenya(COLLINS MUIMI MUSAFIRI, 2020-08) MUSAFIRI, COLLINS MUIMIThe influence of soil fertility management technologies on crop production has widely been researched in Tharaka-Nithi County. However, data on their contribution towards national greenhouse gas budget is scanty. This study aimed at characterising smallholder farming systems and simulating greenhouse gas emissions, maize yields, yield scaled nitrous oxide (N2O) emissions and N2O emission factors from different soil fertility management technologies in Tharaka-Nithi County. Three hundred households were interviewed to obtain data for farming systems characterisation and evaluation of socio-economic factors influencing the diversity of farm typologies. Interview schedules were administered using open data kit collect mobile App. Multivariate analysis was done to characterise smallholder farming systems. To evaluate socio-economic factors influencing farm diversity, Chi-square, t-test, and multinomial regression analysis were carried out using the Statistical Package for Social Sciences (SPSS version 23). For calibration and validation of the DeNitrification DeComposition (DNDC) model, a one-year soil greenhouse gas quantification experiment data were used. The data were obtained from a field experiment conducted in Kigogo primary school. It was laid out in randomised complete block design under four soil fertility treatments as control (no external inputs), inorganic fertiliser (NP, 23.23, 120 kg N ha-1 yr-1), animal manure (goat manure, 120 kg N ha-1 yr-1) and animal manure + inorganic fertiliser (120 kg N ha-1 yr-1) replicated thrice. Climate, soil properties, N2O fluxes, maize yields and farm management data were used. The model was evaluated using modelling efficiency, mean error, coefficient of determination, mean absolute error, and root mean square error (RMSE). The experimental data were subjected to Analysis of Variance in SAS 9.4 software and mean separation done using least significance difference at p = 0.05. The results showed six farm types: Type 1, comprising cash crop and hybrid cattle farmers; Type 2, involving food crop farmers; Type 3, composed of coffee-maize farmers; Type 4, consisting of millet-livestock farmers; Type 5, comprising highly diversified farmers, and Type 6, had tobacco farmers. Land size, total tropical livestock unit, the proportion of land and amount of nitrogen applied to different cropping systems were significant in the construction of farm typologies. The DNDC model was fair in simulating daily N2O fluxes (54% ≤ normalized RMSE (nRMSE) ≤ 68% and 0.26 ≤ modelling efficiency (MEi) ≤ 0.49) and good to excellent performance in simulating cumulative annual soil N2O fluxes (6.16 ≤ nRMSE ≤ 12.86 and 0.63 ≤ MEi ≤ 0.86) across soil fertility treatments. The cumulative observed and simulated annual soil N2O fluxes ranged between 0.21±0.01 and 0.38±0.02 kg N2O-N ha-1 yr-1 and 0.20 kg N2O-N ha-1 yr-1 (control) to 0.38 (fertiliser) kg N2O-N ha-1 yr-1. The simulated N2O yield scaled emissions, and emission factors ranged from 0.022 to 0.029 g N Kg -1 grain yield and 0.03 % to 0.14% under manure and fertiliser treatments, respectively. Based on the low observed and simulated emission factors, using the Intergovernmental Panel on Climate Change (IPCC) Tier 1 default factor of 1% overestimates agricultural soils GHG emissions in the Central Highlands of Kenya. Manure and fertiliser combination should be promoted to enhance the three pillars of climate-smart-agriculture (CSA) as food security, climate change mitigation and adaptation.Item Characterization and selection Anthracnose and Pythium root rot resistance in common bean landraces grown in Kenya(UoEm, 2023-08) Misango, ShamirCommon bean (Phaseolus vulgaris L.) production in Kenya has not reached its potential yield due to various abiotic and biotic factors. Anthracnose, caused by Colletotrichum lindemunthianum and root rots caused by Pythium species are major production constraints. Landraces are preferred by farmers in Kenya due to yield stability and tolerance to some stresses. However, there is little information on the genetic diversity of the landraces and the level of resistance to anthracnose and Pythium root rot. The current study therefore focused on the following objectives (i) to characterize common bean landraces in Kenya based on morphological and simple sequence repeat (SSR) variations, (ii) screen for Pythium root rot and anthracnose resistance among Kenyan landraces and (iii) introgress anthracnose and Pythium resistance genes into farmer-preferred landraces. The study landraces were collected from farmers’ fields and local markets in western, central and eastern Kenya. The genetic diversity within the landraces was determined based on morphological data that was obtained from field experiments and simple sequence repeats (SSRs) markers. Commercial genotypes were included as checks in the study. The results showed significant differences (P≤0.05) among the genotypes for days to 50% flowering, days to plant maturity, leaf length, leaf width, number of pods per plant, number of seeds per pod, pod length, plant height, 100 seed weight and seed yield per plot, indicating high variability among the genotypes. In addition, 51 alleles were obtained from a set of 22 SSR markers, with a mean of 2.32 alleles. Through morphological cluster analysis, 4 distinct clusters were identified. The first cluster consisted of 20 large-seeded genotypes, the second cluster included 39 medium-seeded genotypes with a mixture of determinate and semi-determinate growth habits, the third cluster contained six medium-seeded indeterminate genotypes while the fourth cluster comprised of 34 small-seeded genotypes. Molecular analysis grouped the germplasm into three clusters. Cluster 1 was majorly composed of commercial genotypes of all seed sizes. Cluster 2 comprised of medium seeded genotypes while the third cluster comprised a mixture of genotypes with no unique observation within the clusters. Under greenhouse conditions, majority of the landraces were moderately resistant to anthracnose while most of the small seeded landraces were moderately resistant to Pythium root rot. None of the landraces possessed the molecular markers that are linked to anthracnose and Pythium root rot resistances. Three farmer-preferred landraces were selected for introgression of genes that confer resistance to anthracnose and Pythium root rot. The anthracnose differential cultivar, G2333, was used as the donor parent for anthracnose resistance in a marker assisted backcrossing scheme, while KK 8 was used as the donor parent for Pythium root rot resistance. Utilization of molecular markers enabled the development of 99 lines that carried Co 4 gene (anthracnose) and Pyult1 gene (Pythium). The introgression of disease resistance genes in landraces will ultimately enable bean growers achieve greater yields contributing to high income and improvement of their livelihoods. The information that was obtained from characterization of the landraces will inform breeders on suitable parents to use in breeding programs.Item Characterization and selection Anthracnose and Pythium root rot resistance in common bean landraces grown in Kenya(UoEm, 2023-08) Misango, ShamirCommon bean (Phaseolus vulgaris L.) production in Kenya has not reached its potential yield due to various abiotic and biotic factors. Anthracnose, caused by Colletotrichum lindemunthianum and root rots caused by Pythium species are major production constraints. Landraces are preferred by farmers in Kenya due to yield stability and tolerance to some stresses. However, there is little information on the genetic diversity of the landraces and the level of resistance to anthracnose and Pythium root rot. The current study therefore focused on the following objectives (i) to characterize common bean landraces in Kenya based on morphological and simple sequence repeat (SSR) variations, (ii) screen for Pythium root rot and anthracnose resistance among Kenyan landraces and (iii) introgress anthracnose and Pythium resistance genes into farmer-preferred landraces. The study landraces were collected from farmers’ fields and local markets in western, central and eastern Kenya. The genetic diversity within the landraces was determined based on morphological data that was obtained from field experiments and simple sequence repeats (SSRs) markers. Commercial genotypes were included as checks in the study. The results showed significant differences (P≤0.05) among the genotypes for days to 50% flowering, days to plant maturity, leaf length, leaf width, number of pods per plant, number of seeds per pod, pod length, plant height, 100 seed weight and seed yield per plot, indicating high variability among the genotypes. In addition, 51 alleles were obtained from a set of 22 SSR markers, with a mean of 2.32 alleles. Through morphological cluster analysis, 4 distinct clusters were identified. The first cluster consisted of 20 large-seeded genotypes, the second cluster included 39 medium-seeded genotypes with a mixture of determinate and semi-determinate growth habits, the third cluster contained six medium-seeded indeterminate genotypes while the fourth cluster comprised of 34 small-seeded genotypes. Molecular analysis grouped the germplasm into three clusters. Cluster 1 was majorly composed of commercial genotypes of all seed sizes. Cluster 2 comprised of medium seeded genotypes while the third cluster comprised a mixture of genotypes with no unique observation within the clusters. Under greenhouse conditions, majority of the landraces were moderately resistant to anthracnose while most of the small seeded landraces were moderately resistant to Pythium root rot. None of the landraces possessed the molecular markers that are linked to anthracnose and Pythium root rot resistances. Three farmer-preferred landraces were selected for introgression of genes that confer resistance to anthracnose and Pythium root rot. The anthracnose differential cultivar, G2333, was used as the donor parent for anthracnose resistance in a marker assisted backcrossing scheme, while KK 8 was used as the donor parent for Pythium root rot resistance. Utilization of molecular markers enabled the development of 99 lines that carried Co 4 gene (anthracnose) and Pyult1 gene (Pythium). The introgression of disease resistance genes in landraces will ultimately enable bean growers achieve greater yields contributing to high income and improvement of their livelihoods. The information that was obtained from characterization of the landraces will inform breeders on suitable parents to use in breeding programs.Item Characterization of Smallholder Farming Systems And Greenhouse Gas Emissions Simulation From Maize Cropping System in Tharaka-Nithi County, Kenya(University of Embu, 2020-12-11)The influence of soil fertility management technologies on crop production has widely been researched in Tharaka-Nithi County. However, data on their contribution towards national greenhouse gas budget is scanty. This study aimed at characterising smallholder farming systems and simulating greenhouse gas emissions, maize yields, yield scaled nitrous oxide (N2O) emissions and N2O emission factors from different soil fertility management technologies in Tharaka-Nithi County. Three hundred households were interviewed to obtain data for farming systems characterisation and evaluation of socioeconomic factors influencing the diversity of farm typologies. Interview schedules were administered using open data kit collect mobile App. Multivariate analysis was done to characterise smallholder farming systems. To evaluate socio-economic factors influencing farm diversity, Chi-square, t-test, and multinomial regression analysis were carried out using the Statistical Package for Social Sciences (SPSS version 23). For calibration and validation of the DeNitrification DeComposition (DNDC) model, a oneyear soil greenhouse gas quantification experiment data were used. The data were obtained from a field experiment conducted in Kigogo primary school. It was laid out in randomised complete block design under four soil fertility treatments as control (no external inputs), inorganic fertiliser (NP, 23.23, 120 kg N ha ), animal manure (goat manure, 120 kg N ha -1 -1 yr -1 ) replicated thrice. Climate, soil properties, N2O fluxes, maize yields and farm management data were used. The model was evaluated using modelling efficiency, mean error, coefficient of determination, mean absolute error, and root mean square error (RMSE). The experimental data were subjected to Analysis of Variance in SAS 9.4 software and mean separation done using least significance difference at p = 0.05. The results showed six farm types: Type 1, comprising cash crop and hybrid cattle farmers; Type 2, involving food crop farmers; Type 3, composed of coffee-maize farmers; Type 4, consisting of millet-livestock farmers; Type 5, comprising highly diversified farmers, and Type 6, had tobacco farmers. Land size, total tropical livestock unit, the proportion of land and amount of nitrogen applied to different cropping systems were significant in the construction of farm typologies. The DNDC model was fair in simulating daily N2O fluxes (54% ≤ normalized RMSE (nRMSE) ≤ 68% and 0.26 ≤ modelling efficiency (MEi) ≤ 0.49) and good to excellent performance in simulating cumulative annual soil N2O fluxes (6.16 ≤ nRMSE ≤ 12.86 and 0.63 ≤ MEi ≤ 0.86) across soil fertility treatments. The cumulative observed and simulated annual soil N2O fluxes ranged between 0.21±0.01 and 0.38±0.02 kg N2O-N ha -1 yr ) and animal manure + inorganic fertiliser (120 kg N ha -1 -1 yr (control) to 0.38 (fertiliser) kg N2O-N ha -1 -1 yr and 0.20 kg N2O-N ha -1 -1 yr . The simulated N2O yield scaled emissions, and emission factors ranged from 0.022 to 0.029 g N Kg -1 -1 yr grain yield and 0.03 % to 0.14% under manure and fertiliser treatments, respectively. Based on the low observed and simulated emission factors, using the Intergovernmental Panel on Climate Change (IPCC) Tier 1 default factor of 1% overestimates agricultural soils GHG emissions in the Central Highlands of Kenya. Manure and fertiliser combination should be promoted to enhance the three pillars of climate-smart-agriculture (CSA) as food security, climate change mitigation and adaptation.Item Characterization of Smallholder Farming Systems And Greenhouse Gas Emissions Simulation From Maize Cropping System in Tharaka-Nithi County, Kenya(University of Embu, 2020-12-11) Musafiri, Collins, MuimiThe influence of soil fertility management technologies on crop production has widely been researched in Tharaka-Nithi County. However, data on their contribution towards national greenhouse gas budget is scanty. This study aimed at characterising smallholder farming systems and simulating greenhouse gas emissions, maize yields, yield scaled nitrous oxide (N2O) emissions and N2O emission factors from different soil fertility management technologies in Tharaka-Nithi County. Three hundred households were interviewed to obtain data for farming systems characterisation and evaluation of socioeconomic factors influencing the diversity of farm typologies. Interview schedules were administered using open data kit collect mobile App. Multivariate analysis was done to characterise smallholder farming systems. To evaluate socio-economic factors influencing farm diversity, Chi-square, t-test, and multinomial regression analysis were carried out using the Statistical Package for Social Sciences (SPSS version 23). For calibration and validation of the DeNitrification DeComposition (DNDC) model, a oneyear soil greenhouse gas quantification experiment data were used. The data were obtained from a field experiment conducted in Kigogo primary school. It was laid out in randomised complete block design under four soil fertility treatments as control (no external inputs), inorganic fertiliser (NP, 23.23, 120 kg N ha ), animal manure (goat manure, 120 kg N ha -1 -1 yr -1 ) replicated thrice. Climate, soil properties, N2O fluxes, maize yields and farm management data were used. The model was evaluated using modelling efficiency, mean error, coefficient of determination, mean absolute error, and root mean square error (RMSE). The experimental data were subjected to Analysis of Variance in SAS 9.4 software and mean separation done using least significance difference at p = 0.05. The results showed six farm types: Type 1, comprising cash crop and hybrid cattle farmers; Type 2, involving food crop farmers; Type 3, composed of coffee-maize farmers; Type 4, consisting of millet-livestock farmers; Type 5, comprising highly diversified farmers, and Type 6, had tobacco farmers. Land size, total tropical livestock unit, the proportion of land and amount of nitrogen applied to different cropping systems were significant in the construction of farm typologies. The DNDC model was fair in simulating daily N2O fluxes (54% ≤ normalized RMSE (nRMSE) ≤ 68% and 0.26 ≤ modelling efficiency (MEi) ≤ 0.49) and good to excellent performance in simulating cumulative annual soil N2O fluxes (6.16 ≤ nRMSE ≤ 12.86 and 0.63 ≤ MEi ≤ 0.86) across soil fertility treatments. The cumulative observed and simulated annual soil N2O fluxes ranged between 0.21±0.01 and 0.38±0.02 kg N2O-N ha -1 yr ) and animal manure + inorganic fertiliser (120 kg N ha -1 -1 yr (control) to 0.38 (fertiliser) kg N2O-N ha -1 -1 yr and 0.20 kg N2O-N ha -1 -1 yr . The simulated N2O yield scaled emissions, and emission factors ranged from 0.022 to 0.029 g N Kg -1 -1 yr grain yield and 0.03 % to 0.14% under manure and fertiliser treatments, respectively. Based on the low observed and simulated emission factors, using the Intergovernmental Panel on Climate Change (IPCC) Tier 1 default factor of 1% overestimates agricultural soils GHG emissions in the Central Highlands of Kenya. Manure and fertiliser combination should be promoted to enhance the three pillars of climate-smart-agriculture (CSA) as food security, climate change mitigation and adaptation. -1Item Contributions of Anthropogenic Activities to Leaf Litter Decomposition in River Kapingazi, Embu County, Kenya(University of Embu, 2021-09) Nyambane, Neliah MoraaHuman activities have potential adverse effects on freshwater ecosystems, which sustain a wide range of ecosystem services such as the provision of potable water, nutrient cycling, and a habitat for organisms such as decomposer macro-invertebrates. The effect of these activities with regard to water quality and invertebrates has been established and well documented. However, information on the effect of human activities on leaf litter breakdown as an indicator of river ecosystem integrity is still limited in Kenya. The objectives of the study were: To determine effect of anthropogenic activity on litter decomposition rates of Lantana camara, Eucalyptus grandis and Psidium guajava; to compare leaf litter decomposition rates of the three species and To examine relationships between leaf litter decomposition rates, macro invertebrate shredders and water quality parameters. The study employed the litterbag method where dry leaves enclosed in mesh bags were incubated in the river to measure mass loss decomposition and associated macro invertebrates. Data was collected from September to December 2018.iThe Physicochemical characteristics of water measured in-situ included electrical conductivity (EC), pH, total dissolved solids, dissolved oxygen (DO) concentration and temperature. Further, water discharge, velocity, depth and width were determined. Laboratory analyses were conducted to determine concentration of nitrates, nitrites, total phosphorus and phosphates. Daily mass loss of the collected bags was determined to assess litter decomposition rates. Macro invertebrates identified were classified up to family level and grouped into functional feeding groups. Data was analyzed using R statistical packages. Findings show that site and plant species had a significant effect (p=0.05) on leaf litter decomposition rates. Of the three species, Lantana camara had the fastest decomposition irate while Psidium guajava had the slowest irate of decomposition. Water physicochemical parameters had both positive and negative correlation with leaf litter decomposition rates and no macro invertebrate shredders were observed. It is recommended that future studies should evaluate other human activities (for example, mining and waste water effluents) and effects of leaf litter mixtures on the decomposition process.Item Effect of Tillage Methods and Nutrient Application Levels on Soil Properties and Soghum and Greengram Yields in Siakago, Embu County, Kenya(LILY GICUKU NJIRU, 2024-08) Njiru, Lily GicukuDeclining soil fertility is a significant constraint to sorghum and green gram yields for smallholder farmers in semi-arid regions of Kenya. This research was carried out in Siakago, Embu County, Kenya, with the aim of assessing the efficacy of different tillage methods and inorganic and organic fertilizers for sorghum and green gram production. The research was performed for four consecutive seasons from October 2018 to February 2021 at the Agricultural Technology Development Centre, Siakago in Mbeere North sub-County. In the study, there were a total of 24 different treatments using a randomized full block design with three replicates. The treatments comprised of two different types of tilling, namely conventional and tied ridges, three cropping systems (sole-green grams, sole-sorghum, and green grams + sorghum intercrops) and four soil fertility input regimes (no inputs), (60 kg DAP ha-1 ), (5.0 t ha-1 manure) and a combination of manure and inorganic fertilizer as (2.5 t ha-1 + 30 kg DAP ha-1 ). Soil properties, including organic carbon, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron, zinc, and copper, were analyzed before and after the experiment. Crop parameters, such as days to 50% flowering, plant height, leaf chlorophyll content, biomass, and grain yields, were also measured. The treatment effects were analyzed using ANOVA, and a significance level of p ≤0.05 was used to differentiate the treatment means using post hoc Turkey’s HSD test. Differences in treatment means were analyzed using Fisher's test for the test with the least significant difference, which was performed at a significance level of p ≤ 0.05. The results showed that tied ridge tillage practice significantly increased exchangeable phosphorus and magnesium contents. The green gram cropping system registered higher but insignificant nutrient status compared to sole sorghum or sorghum-green gram cropping systems. Organic-based fertility inputs positively affected soil organic carbon, although these increases were not statistically significant. Soil inputs significantly influenced soil carbon concentrations, with the lowest values observed in the control treatment. The study found that sorghum supplied with full-rate inorganic fertilizer had greener leaves and produced 75% higher grain than in the control. The pure farmyard manure treatment produced 45% more grain compared to the control. Tied ridges did not significantly increase yields p ≤ 0.05. Similar trends were observed in green grams. This research emphasizes the significance of applying soil conservation techniques, such as tied-ridging, in conjunction with organic input applications, to improve the availability of multiple nutrients for better crop performance and human nutrition in dryland farming systems.Item Effects of Tillage and Mulching on Maize Yield, Soil Water Content and Organic Carbon in Kirige, Tharaka-Nithi County. Kenya(University of Embu, 2016-09) Njogu, Evelyn W.Sustainable agricultural production in Kenya requires improvement of yields per unit of land while still conserving soil resources. Besides poor soil nutrient status, water is a limiting factor to crop production in the rain-fed farming systems of central highlands of Kenya. Hence, there is need to address soil water scarcity challenges in order to increase crop production. The objective of the study was to determine the effects of tillage and mulching on maize (Zea Mays. L) yield, soil water content and organic carbon of Humic nitisols in the central highlands of Kenya. The study was conducted in Tharaka-Nithi County, Meru South Sub-County at Kirege for two seasons (long rains 2014 and short rains 2014). Two mulch levels; removal (W) and retention (R) of crop residue were applied randomly to plots measuring 7 m by 7 m under two tillage methods; conventional tillage (CT) and minimum tillage (MT). The treatments arrangement was a split-plot laid down in a randomized complete block design. Data on soil organic carbon, soil moisture, grain and biomass yield was subjected to Analysis of variance (ANOVA) using the mixed model in SAS 9.3. The soil organic carbon content data at the beginning and end of the experiment was subjected to student t-test for pair wise comparisons using the mixed model in SAS 9.3. Difference between treatment means was tested using least significant difference at 5% level of significance. The results showed significant tillage (p=0.0042) and mulching (p=0.0255) singular effect on maize yield. Combining tillage and mulching significantly (p=0.039) increased maize stover and grain yields. Overall, conventional tillage with residue treatment gave the highest increase in stover yield by 72%. Minimum tillage with residue and without residue, increased grain yield by over 50% compared to conventional tillage with and without residue. In the short term, soil water was not significantly influenced singly by tillage and mulching but it was positively influenced by tillage and mulch combination. On average, minimum tillage with residue and without residue increased soil moisture content by 10 and 7%, respectively compared to control, while Conventional tillage with residue and without residue increased moisture by 4 and 3% respectively. Tillage alone significantly (p=0.01) affected soil organic carbon content while mulching alone did not. There was significant (p=0.01) increase in soil organic carbon under minimum tillage as opposed to the reduction under conventional tillage at the 0–0.2 m soil depth. Combining tillage and mulching resulted to higher soil organic carbon content. Minimum tillage with residue, increased soil organic carbon by 0.33% more than minimum tillage alone. Short-term implementation of minimum tillage and mulching under the soil and climate conditions prevailing in Kirege Tharaka-Nithi County enhances maize production while improving soil conditions in terms of soil moisture and organic carbon content.Item Effects of Tillage Method and Sowing Time on Growth, Water Use and Yield of Chickpea (Cicer arietinum L.) in Kenyan Dry(Egerton University, 2007) Onyari, Charles N.The need to provide sufficient protein food for an increasing population that is mainly resource poor requires opening up of marginal land for growing appropriate pulsessuch as chickpea. An experiment was carried out at KARI-Naivasha situated at an altitude of 1900 m, characterized with clayey to sandy loam soils in a split plot of randomized complete block design over two seasons (December 29, 2004 to May 26, 2005 and June 21 to November 15, 2007). The objective was to investigate the production of kabuli chickpea in Kenya as affected by tillage methods (main plots) and sowing times (subplots) and the effects of these factors on water use and yield ofthe crop. The overall mean height ranged from 39.7 to 47.7 cm under tillage methods with strip tillage resulting in relatively taller plants than the other tillage methods. Sowing times gave plant heights of 41.5 – 46.4 cm with early sown crops being relatively taller than late sown crop in both seasons. The leaf area index ranged from 2.50 to 3.31 and 4.22 to 5.44 under tillage methods in Season I and II, respectively. The corresponding valuesof LAI in the respective two seasons under sowing times were 2.80 to 3.20 and 3.59 to 5.69. Thecrop took 32.5 to 35.5 days to first flower and 61.8 to 61.4 days to 50% flowering in Season I and II, respectively. The mean time to physiological maturity was 120 days showed significant differences among tillage methods in both seasons. The time to first flower and 50% flowering however had non-significant differences (P<0.05) under both tillage method and sowing time treatments. The aboveground biomass yield of the chickpea varied from 3242.1 to 4231.3 kg ha -1 in Season I and 3035.8 to 4556.1 kg ha -1 in Season II under varying tillage treatments. The sowing time effects on biomass yield showed significant differences in biomass yields ranging between 3784.3 to 4095.0 kg ha -1 and 2938.1 to 4263.2 kg ha -1 in Season I and II, respectively. The grain yields obtained were significantly different (P<0.05) ranging from 1430.6 to 2544.9 kg ha -1 under tillage method effects and 1573.8 to 2235.3 kg ha -1 under sowing time treatment effects in both seasons. Tillage and sowing time effects on grain yield of chickpea were significantly different (P<0.05) only in the second season. In Season I, rains received in the post anthesis period of the chickpea thus causing it to exhibit indeterminate growth habit which resulted in additional yield increments of between 26.2 to 29.8% and 23.3 to 35.0% under various tillage and sowing time treatments, respectively. This gave a final overall mean grain yield of 2058.4 ka ha -1 . The 100-grain weight of the chickpea varied between 36.7 to 40.2 g in both seasons and showed non-significant differences under both factors of study. Infiltration rates were not significant under tillage and sowing times but affected the storage capacity ranging between 450.3 mm for first sowing time in Season II to 488.1 mm for conventional tillage in Season I. The mean seasonal evapotranspiration varied between 300.1 mm to 326.1 mm and showed interaction effects between tillage and sowing times in Season II. The mean biomass based water use efficiency (WUE b) and grain based water use efficiency (WUE g) ranged from 12.09 to 12.21 kg ha-mm -1 and 4.93 to 6.31 kg ha-mm -1 in Season I and II, respectively. The moisture use rate was non-significant with ranges of 2.23 to 2.58 and 2.18 to 2.56 mm/day in Seasons I and II, respectively.Item Effects of Tillage Method and Sowing Time on Growth, Water Use and Yield of Chickpea (Cicer arietinum L.) in Kenyan Dry Highlands(2010) Onyari, Charles N.The need to provide sufficient protein food for an increasing population that is mainly resource poor requires opening up of marginal land for growing appropriate pulses such as chickpea. An experiment was carried out at KARI-Naivasha situated at an altitude of 1900 m, characterized with clayey to sandy loam soils in a split plot of randomized complete block design over two seasons (December 29, 2004 to May 26, 2005 and June 21 to November 15, 2007). The objective was to investigate the production of kabuli chickpea in Kenya as affected by tillage methods (main plots) and sowing times (subplots) and the effects of these factors on water use and yield of the crop. The overall mean height ranged from 39.7 to 47.7 cm under tillage methods with strip tillage resulting in relatively taller plants than the other tillage methods. Sowing times gave plant heights of 41.5 – 46.4 cm with early sown crops being relatively taller than late sown crop in both seasons. The leaf area index ranged from 2.50 to 3.31 and 4.22 to 5.44 under tillage methods in Season I and II, respectively. The corresponding values of LAI in the respective two seasons under sowing times were 2.80 to 3.20 and 3.59 to 5.69. The crop took 32.5 to 35.5 days to first flower and 61.8 to 61.4 days to 50% flowering in Season I and II, respectively. The mean time to physiological maturity was 120 days showed significant differences among tillage methods in both seasons. The time to first flower and 50% flowering however had non-significant differences (P<0.05) under both tillage method and sowing time treatments. The aboveground biomass yield of the chickpea varied from 3242.1 to 4231.3 kg ha-1 in Season I and 3035.8 to 4556.1 kg ha-1 in Season II under varying tillage treatments. The sowing time effects on biomass yield showed significant differences in biomass yields ranging between 3784.3 to 4095.0 kg ha-1 and 2938.1 to 4263.2 kg ha-1 in Season I and II, respectively. The grain yields obtained were significantly different (P<0.05) ranging from 1430.6 to 2544.9 kg ha-1 under tillage method effects and 1573.8 to 2235.3 kg ha-1 under sowing time treatment effects in both seasons. Tillage and sowing time effects on grain yield of chickpea were significantly different (P<0.05) only in the second season. In Season I, rains received in the post anthesis period of the chickpea thus causing it to exhibit indeterminate growth habit which resulted in additional yield increments of between 26.2 to 29.8% and 23.3 to 35.0% under various tillage and sowing time treatments, respectively. This gave a final overall mean grain yield of 2058.4 ka ha-1. The 100-grain weight of the chickpea varied between 36.7 to 40.2 g in both seasons and showed non-significant differences under both factors of study. Infiltration rates were not significant under tillage and sowing times but affected the storage capacity ranging between 450.3 mm for first sowing time in Season II to 488.1 mm for conventional tillage in Season I. The mean seasonal evapotranspiration varied between 300.1 mm to 326.1 mm and showed interaction effects between tillage and sowing times in Season II. The mean biomass based water use efficiency (WUEb) and grain based water use efficiency (WUEg) ranged from 12.09 to 12.21 kg ha-mm-1 and 4.93 to 6.31 kg ha-mm-1 in Season I and II, respectively. The moisture use rate was non-significant with ranges of 2.23 to 2.58 and 2.18 to 2.56 mm/day in Seasons I and II, respectively.Item Enhancing Soybean Production, Economics and adoption among Smallholder Farmers in the Central Highlands of Kenya(University of Embu, 2019-08) Murage, Francis M.Current demand for soybean in Kenya is higher than production. The deficit which is over 95% is filled through importation from neighboring countries. Despite the high demand, adoption and production is low (0.56 to 1.1 t ha-1) against potential yield of 3.0 – 3.6 t ha-1. The low production is associated with low use of fertilizers. Farmers are using mineral fertilizers below recommended rates and they are not using organic fertilizers despite them being readily available. The objectives of the study was therefore to determine the effect of applying organic and inorganic fertilizers singly or in combination on grain yield of soybean, compare economics of soybean under organic and inorganic fertilizers and to determine factors influencing adoption of soybean by smallholder farmers in the central Highlands of Kenya. To achieve these objectives, on-farm experiments were set in Embu County and a survey was carried out in Embu, Meru and Tharaka Nithi Counties. The experiments had six treatments; (tithonia, tithonia plus fertilizer, fertilizer plus manure, fertilizer, manure and a control) arranged in Randomized Complete Block Design (RCBD). The plot sizes measured 6 m × 4.5 m and the main data collected was yield and labour. In the survey, the sample size was 210 farmers. Net benefits, benefit cost ratio and return to labor were used as the economic tools in data analysis. All biophysical data was subjected to analysis of variance (ANOVA). To determine factors influencing adoption of soybean, data was subjected to Cross-tabulation for categorical variables to test for association using Pearson chi-square statistic, the data was also subjected to a binary logistic regression model to predict the factors affecting adoption of soybean in the central highlands of Kenya. Results showed that there was a significant difference in soybean yield among treatments in LR 2016 and SR 2016, (P= <0.0001) and (P= <0.0033) respectively. A combination of manure plus fertilizer and tithonia plus fertilizer recorded a significant higher soybean yield than the control in both seasons. Manure plus fertilizer recorded a significantly higher net benefit and return to labour than the control in both seasons and it is the only treatment that recorded a return to labour of greater than 2.0, which is the minimum acceptable for smallholder farming activities. Out of 210 households interviewed, 41% were adopters while 59% were non-adopters. Total farm size, membership of a farmer group and attendance of training on soybean positively influenced adoption of soybean while age of household head negatively influenced adoption of soybean. The implication of these results is that farmers should be integrating organic and inorganic fertilizer in soybean farming in Embu County. Integration of manure and fertilizer should be advocated for in order to realize maximum economic benefits from soybean farming. Further, the adoption of soybean in the central Highlands of Kenya can be enhanced by targeting young household heads, household heads with bigger farm sizes, encouraging farmers to join farmer groups and increasing trainings on soybean. These findings provide a guide to the extension agents in the Ministry of Agriculture, Livestock and Fisheries (MoALF) in Embu, Meru and Tharaka Nithi Counties. This will help them in designing training manuals for farmers in regard to soybean production and increasing adoption of the crop in these Counties.Item Integrated Soil Nutrient Management Technologies for Improved Maize (Zea Mays L.) Productivity in Murang’a and Tharaka-Nithi Counties, Kenya(University of Embu, 2018-09) Otieno, Erick OduorContinuous land cultivation without adequate soil nutrients replenishment causes soil fertility decline leading to reduced crop productivity. Significant research on external fertility inputs application rates and type have been carried out under researcher designed and managed conditions in Kenya. But little research on the same has been carried out to evaluate their performances under on-farm smallholder farmers’ conditions. Hence, the study evaluated the decomposition rates (goat manure and Tithonia diversifolia) and performance of selected integrated soil nutrients management technologies on soil nutrients amounts and maize productivity under two tillage methods. On-farm trials were laid out in randomized incomplete block design. There were two control treatments; conventional tillage-control (CON-C) and minimum tillage-control (MIN-C). Each tillage method was combined with different soil fertility inputs. Soil fertility inputs included mineral fertilizer, rock phosphate, crop residue, legume intercrop, goat manure and Tithonia diversifolia. Compared to CON-C, in Meru South, N and K significantly increased under minimum tillage+crop residue+Tithonia diversifolia+goat manure and minimum tillage+crop residue+Tithonia diversifolia+rock phosphate by 100 and 52%, respectively. In Gatanga, nitrogen, phosphorus and potasium significantly increased under minimum tillage+mineral fertilizer, conventional tillage+crop residue+mineral fertilizer+goat manure and minimum tillage+crop residue+goat manure+legume intercrop by 33, 78 and 34%, respectively. The highest decomposition rate constants were 0.024 and 0.015 d-1, and 0.020 and 0.014 d-1 for Tithonia diversifolia and goat manure in Meru South and Gatanga, respectively. Relative to CON-C, minimum tillage+crop residue+Tithonia diversifolia+rock significantly increased maize grain yield by 89 and 91% in Meru South and Gatanga during SR2016 and LR2016, respectively. The selected soil nutrient management technologies were preferred based on the ability to improve soil fertility, crop yield, ease of implementation, availability of inputs and labour and farmer’s age. The study concludes that selected soil nutrients technologies improve soil fertility and maize grain and stover yields thus are likely to be taken up by farmers. Tithonia diversifolia and goat manure can be used to synchronize crop-nutrient release.Item Marker assisted Selection for resistance to bean common Mosaic Necrosis virus In French Bean cultivars in Kenya -(UoEm, 2023-08) Watare, Grace WambuiWorldwide, commercial production of French bean (Phaseolus vulgaris L.) is constrained by diseases, key among them being the bean common mosaic virus (BCMV) and bean common mosaic necrosis virus (BCMNV). These potyviruses are the most devastating to common bean farmers and can cause total yield loss under heavy infestation. The objective of this study was to characterize the BCMNV resistance in commercial French bean cultivars and initiate a breeding program against the disease. A set of 32 entries, comprising 27 French bean genotypes together with 5 dry bean varieties were evaluated for resistance under field conditions. All the 29 French bean genotypes showed susceptibility to BCMNV but the 3 dry bean resistant checks (MCM 2001, MCM 5001 and MCM 1015) were resistant to the disease. The French bean cultivars displayed varied reactions to BCMNV pathotypes III and VI under greenhouse conditions ranging from top necrosis, mosaics, mottling, and deformed leaves to stunted growth. In this study, molecular marker SW13 and SBD5 were used to detect the presence of the I gene and the bc-12 gene, respectively. ROC11 and CAPS elF4E that are linked to BCMNV bc-3 gene, were also used to detect specific resistance genes. Molecular analyses showed that only SW13 and elF4E markers were consistent in identifying the presence/absence of the I and bc-3 gene, respectively. The two molecular markers and ROC-11 were successfully utilized in the introgression of bc-3 gene into three commercial French bean cultivars (Amy, Serengeti and Vanilla) in a backcross breeding program involving MCM 2001, MCM 5001 and MCM 1015 as donor parents. From the breeding program, 19 breeding lines combining field resistance against both BCMNV and BCMV were developed. The selected lines were further phenotypically evaluated for quality and yield traits such as pod length, pod quality, pod suture string, pod wall fiber, pod yield and the number of pods per plant. The results confirmed significant maintenance of the yields and quality traits among the 19 selections. The developed breeding lines will be further screened and improved for release as new French bean cultivars thus enabling the production of this valuable vegetable in areas where these potyviruses are prevalent. In addition, the developed lines can be utilized as sources of BCMNV resistance in future breeding programs. Availability of reliable sources of BCMNV resistance within French bean gene pool will simplify the future breeding programs.