RP-Department of Environmental Science

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Accumulation of heavy metals on bed sediments of Nairobi dam, Kenya
(Academic Journals, 2017-03) Ndeda, L. A.; Manohar, S.; Macharia, G. M.
Globally heavy metals pollutants in aquatic systems are increasing and creating major ecological disturbance(s) and direct health problems. The study on accumulation of Copper (Cu), Cadmium (Cd), Lead (Pb) and Nickel (Ni) on the bottom surface sediments of Nairobi dam was conducted between November 2012 to April 2013. Seven sampling sites were selected within the dam and sediment samples were collected once in a month during the wet and dry season. Standard methods for sampling, storage and analysing according to APHA were used; statistical analysis in form of means, independent T-test and ANOVA were used to summarize the findings. (Mean±SE) (ppm) concentrations of Pb, Cd, Cu and Ni in the dam during the dry season are: 38.01±0.26, 30.86±0.21, 21.7±0.22, 8.44± 0.15, and in wet season are: 33.73±0.22, 26.60±0.19, 19.11±0.14 and 5.94±0.12, respectively. The levels of heavy metals in the sediments at the outlet are lower compared to the other sites within the dam. These metals accumulated in the order: Pb> Cd> Cu> Ni with higher concentration during the dry than wet season. It is concluded Nairobi dam sediments are contaminated with heavy metals that are significantly higher during the dry compared to wet season (P<0.0001). Therefore it is recommended that sediments of this dam are not suitable for cultivation and or any agricultural activities
Adolescent transition to coitus and premarital childbearing in sudan: a biosocial context
(Cambridge University Press, 1999) Otor, S.C.J.; Pandey, Arvind
Adoption and Utilisation of Zai Pits for Improved Farm Productivity in Drier Upper Eastern Kenya
(Journal of Agriculture and Rural Development in the Tropics and Subtropics, 2020) Kimaru-Muchai, Serah Wairimu; Ngetich, Felix K; Baaru, Mary; Mucheru-Muna, Monicah Wanjiku
Inadequate and poorly distributed rainfall and declining soil fertility have led to low crop productivity in most smallholder farms in sub-Saharan Africa. As a result, there has been a renewed quest for sustainable and resource-use efficient agricultural production practices. Zai pit technology is a practice that has the potential to alleviate water stress and enhance soil fertility. We assessed the factors that influence farmers’ adoption and utilisation of Zai pits in Tharaka-Nithi County in upper Eastern Kenya. We interviewed 291 farm household heads. Descriptive statistical analysis and a logistic regression model were applied to evaluate socio-economic factors that affect the adoption of Zai pits by farmers. Binary logistic regression estimation revealed that the number of non-formal training, beneficiaries of nongovernmental organisations, wealth status and membership of a social group play an essential role in the adoption of Zai pits. Based on the findings, we recommend that farm characteristics and socio-economic characteristics of farmers should be considered in the promotion of Zai pits as a water harvesting technology. The results of the study will be useful to extension service providers in planning, designing and evaluating effective and efficient agricultural policies, programs and projects at local, regional and national scales in the dissemination of Zai pit technology among smallholder farmers in the semi-arid tropics.
Adoption of Climate Change Friendly New Rice For Africa (NERICA) Varieties among Farmers in Mwea West Sub-County, Kenya
(AJEST, 2022) Mburu, Benson Kamau; Ngucia, Christine Wanjiku
Climate change and inefficient water utilization have led to marked fluctuations of the mean rice crop production in sub-Sahara Africa. In order to improve food security and households’ income, adaptation strategies to climate change such as the adoption of new rice varieties are inevitable. This study examined the farmers’ perception and adoption of climate change friendly New Rice for Africa in Mwea West Sub-county. The study applied the descriptive survey design with questionnaires being administered to a sample of 376 farmers. Key informants included four officers from Mwea Irrigation Agricultural Development and the Ministry of Agriculture. Quantitative data were analysed using Statistical Package for Social Sciences whereas qualitative data were analysed through establishing the categories and themes, relationships/patterns, and conclusions drawn in line with the study objectives. Results indicated a highly significant difference in adoption between farmers affiliated to Mwea Irrigation Scheme and the out-growers (X2 = 18.5, df =2, p= 1.67×10-6 ). The study concluded that the adoption of New Rice for Africa varieties in the Mwea West Sub-county is low and slow. This is mainly caused by inadequate information among the farmers as well as low market demand for the rice varieties. There is a need to enhance these rice varieties by intensifying efforts to sensitize farmers.
Adoption potential of selected organic resources for improving soil fertility in the central highlands of Kenya
(Springer Science+Business Media B.V., 2009) Mugwe, J.; Mucheru-Muna, M.; Mugendi, D.; Kung’u, J.B.; Bationo, A.; Mairura, F.
Soil fertility decline is the major cause of declining crop yields in the central highlands of Kenya and elsewhere within the African continent. This paper reports a study conducted to assess adoption potential of two leguminous trees, two herbaceous legumes, cattle manure, and Tithonia diversifolia either solely applied or combined with inorganic fertilizer, for replenishing soil fertility in the central highlands of Kenya. The study examined biophysical performance, profitability, feasibility and acceptability, and farmers experiences in managing and testing the inputs. The study was based on a series of studies incorporating both sociological and experimental approaches for two and a half years.Results of on farm trials showed that manure ? fertilizer and tithonia ? fertilizer treatments increased yields by more than 100% above the control. These treatments were the most profitable having highest net benefits and benefit cost ratios. They were also the most commonly preferred by farmers who used them on larger plots compared to the other inputs. In conclusion, cattle manure and tithonia were found to be the organic materials with the highest adoption potential for soil fertility improvement in this area. Calliandra calothyrsus and Leucaena trichandra, on the other hand, have potential for use as animal fodder. The herbaceous legumes had the least adoption potential due to poor performance recorded onthe farms that possibly led to low preference by the farmers. However, issues of sustainable seed production could have played a role. This study recommends some policy issues for enhancing adoption and research issues focusing on exploring strategies for increasing biomass production and use efficiency on farms.
Agroforestry Technologies Adopted by Smallholder Farmers In Southern Province of Rwanda
(East African Nature & Science Organization, 2019) Mukundente, Liliane; Ndunda, Ezekiel; Gathuru, Gladys
Agroforestry is an agricultural system that deliberately integrates trees, crops and animals on the same land and under the same management. Agroforestry practices have the ability to counter the increasing food insecurity and offers several outputs (e.g. enhanced crop production, money and job opportunities) to smallholder farmers hence the improvement of rural living standards. This paper focuses on the agroforestry practices adopted by smallholder farmers, challenge faced and the benefits derived from the agroforestry practices. This study was carried out in four districts in the Southern Province of Rwanda. A descriptive survey design was used in this study. The study adopted a stratified random sampling technique for questionnaire distribution. Descriptive methods of analysis were used to identify the different agroforestry technologies adopted by smallholder farmers in Rwanda. This study illustrated the different agroforestry practices adopted by farmers. The results revealed that most farmers in the Southern Province adopted boundary planting agroforestry followed by homegardens, alley cropping and scattered trees on farm. Most adopters (68%) of agroforestry planted trees around their farms. The farmers maintained that these trees are retained to provide various uses (e.g. fuel wood, staking material, constructional materials, grazing, climate regulation, soil erosion, control of wed and pest, reduction of crop failure, improving soil fertility, nutrient recycling and nitrogen fixation). Input and productivity were the common challenges faced by the farmers who adopted agroforestry practices. Most of the respondents were able to access the necessary information on the importance of agroforestry, attained knowledge for planting trees (especially in spacing and management skills) and knowledge about various species of trees and management skills. The government of Rwanda and other stakeholders should promote tree farming in the area so as to prevent deforestation and land degradation in search of firewood and timber from the community and government forests.
Agronomic and Economic Performance of Legume-Legume and Cereal-Legume Intercropping Systems in Northern Tanzania
(Elsevier, 2023) Kinyua, M.W; Kihara, J; Bekunda, M; Bolo, P; Mairura, F.S; Fischer, G; Mucheru-Muna, M.W
CONTEXT: Cereal-legume intercropping, a common practice among farmers in sub-Saharan Africa (SSA), is important for crop diversification, soil fertility improvement, household nutrition and climate adaptation. However, cereals often outcompete the intercropped legumes for growth resources resulting in low legume yields. OBJECTIVE: The objectives of this study were: i) assessing the effects of different intercropping options (crop spatial configurations) and maize crop (Zea mays L.) management innovations on productivity and economic benefits to farmers and ii) examining how farmers adapt new intercropping technologies to meet their household food security needs. METHODS: The study was undertaken in six on-farm researcher-designed and managed trials in high and low rainfall agro-ecological zones of Babati District in Tanzania, during four cropping seasons (2018–2021). The cropping systems tested included a sole maize system rotated with a legume-legume intercrop (Doubled-up legume), an innovation involving two maize rows intercropped with two legume species (Mbili-Mbili), maizelegume intercrop both with and without de-topping, maize-legume intercrop (2 maize plants at 50 cm intraspace, de-topped), maize-legume system (maize with vertical leaf architecture) and a farmer practice. The Mbili-Mbili technology adaptation assessment was conducted on 225 farmers during the 2021 cropping season. RESULTS AND CONCLUSIONS: Overall, maize grain yields increased by up to 56% in improved compared to farmer intercropping practices (P ≤ 0.05). There were no significant differences in maize grain yield among the improved practices. Significantly higher pigeonpea (Cajanus cajan) yields of between 71% and 113% in 2020 and between 65% and 140% in 2021 were observed under Doubled-up legume and between 63% and 124% under local farmer practices in 2020 than in the improved cereal-legume practices. Across the study period, net revenues of sole maize and Doubled-up legume rotations were both the highest and lowest relative to other intercropping options, depending on the starting phase (US$ 653 sole maize and US$ 326 legume phase starting). These were also associated with the highest variances indicating instability. Mbili-Mbili intercropping system had not only high net revenue i.e., a mean of US$623 per hectare, but also more stable. Farmers perceived that Mbili-Mbili increased food security and 96% were willing to implement the system without project support. SIGNIFICANCE: Mbili-Mbili is recommended for adoption by farmers because of its potential economic benefits, food security and resilience in the current unpredictable weather and climate patterns.
Alley cropping of maize with calliandra and leucaena in the subhumid highlands of Kenya: Part 2. Biomass decomposition, N mineralization, and N uptake by maize
(Kluwer Academic Publishers, 1999) Mugendi, D.N.; Nair, P. K. R.; Mugwe, J. N.; O'Neill, M. K.; Swift, M. J.; Woomer, P.
A major challenge in developing agroforestry approaches that utilize tree-leaf biomass for provision of N to crops is to ensure synchrony between the N released from decomposing prunings and N demand by crops. A study was conducted in the subhumid highlands of Kenya to assess the rate of decomposition and mineralization of soil-incorporated Calliandra calothyrsus Meissner (calliandra) and Leucaena leucocephala (Lam.) de Wit (leucaena) tree biomass and maize roots (Zea mays L.) both in an alley cropping and a sole cropping system. The amount of mineralized N peaked four weeks after planting (WAP) maize in all the treatments during both seasons of 1995. Cumulative mineralized N at week 20 ranged from 114 to 364 kg N ha−1 season−1, the absolute control treatment giving the lowest and the prunings-incorporated treatments giving the highest amounts in the two seasons. Total N uptake by maize, ranging from 42 to 157 kg ha−1 season−1, was lowest in the 'alley-cropped, prunings-removed' treatments, and highest in the 'non alley-cropped-prunings-incorporated' treatments. The apparent N recovery rate by maize was highest in the fertilizer applied treatments in the two seasons. Decomposition rate constants (kD) ranged from 0.07 to 0.21 week−1, and the rates among the different plant residues were as follows: leucaena < calliandra < maize roots. Nitrogen release rate constants (kN), ranging from 0.04 to 0.25 week−1, followed a similar pattern as the rate of decomposition with leucaena releasing the highest amount of N followed by calliandra and lastly by maize roots.
Analysis of Household Energy Sources and Woodfuel Utilisation Technologies in Kiambu, Thika and Maragwa Districts of Central Kenya
(Academic Journals, 2012-02-01) Mugendi, D.N.; Kung'u, J.B.; Githiomi, J.K.
This study was carried out in Kiambu, Thika and Maragwa districts of Central Kenya. Its objective was to analyze household energy sources and utilization technologies used. Primary data was collected from households using structured and non structured questionnaires. Trees on farm were found to be the major supply of the woodfuel energy where firewood was the main source of household energy followed by charcoal. Traditional three stones stoves were the most commonly used with 76 59 and 65 (household respondents) in Kiambu, Thika and Maragwa districts respectively. Improved charcoal stoves were the second commonly used while only a very negligible percentage used kerosene stoves and gas burners. Over 70% of the respondents were aware of the improved stoves but their adoption was less than 29%. The low adoption of improved stoves was due to their high cost as noted by the respondents. Over 90% of the households had the opinion that woodfuel sources were decreasing and there was a need to develop strategies for its future sustainability. The study recommended integration of woodfuel production to local farming systems and establishment of fuelwood plantations by Kenya Forest Service to substitute on farm sources. It also recommended promotion of improved stoves with higher efficiency to reduce the woodfuel used as well as improve on environmental pollution.
Annonated Checklist of Plant Species of Loita Forest (Entim E Naimina Enkiyio Forest or the Forest of the Lost Child), Narok County, Kenya
(IJARBS, 2019) Mbuvi, Musingo Tito E.; Kungu, James B.; Gachathi, Francis N.; Wekesa, Chemuku; Leley, Nereoh; Muthini, Joseph M.
An ethnobotanical survey was undertaken in Loita forest from 2012 to 2015 to document species richness and compile the first comphrensive plant species checklist of Loita forest. The forest is located in Narok County, Loita Sub County, an area occupied by the Loita Maasai community. Purposive sampling using established plots and transects walks was carried out for complete documentation of all plant species existing in the forest. Focused group discussions and key informant interviews were undertaken to confirm the local names of the species. The plants were identified and confirmed at the East Africa Herbarium; National Museusm of Kenya. The checklist outlines the plant species in botanical and Maasai names and their corresponding families. The plant species have been arranged alphabetically using their scientific names. The checklist developed shall be crucial for future ecological studies and management of Loita forest. The checklist can be updated through future botanical surveys.
Anthropogenic Factors that Causes Floods in Mukuru Slums, Nairobi City County, Kenya
(European International Journal of Science and Technology, 2019) Kaburu, Munene; Koech, Michael; Manguriu, Daniel
Urban slums are facing increased challenges of flooding scenarios that hinder their development. Increased flooding events in informal urban settlements can be attributed to humankind alteration of the environment. The study sought to determine anthropogenic factors that caused floods occurrence in Mukuru slum. The study used a cross-sectional survey research design. Stratified random sampling technique was used to collect data from a sample size of 100 respondents. According to the study findings, 32%, 28% and 19% of the respondents stated that poor solid waste disposal, uncontrolled development and clearing vegetation along rivers and wetlands respectively triggered the occurrence of floods in the study area. Human alterations also led to changes in land use land cover patterns in the area. The integral recommendations of the study were: demolition of illegal houses built above the open drains and riparian reserves, restoration of wetlands that act as floods buffer zones by planting trees.
Anthropogenic Impacts on Land Use and Land Cover Change in Ombeyi wetland, Kisumu County, Kenya
(Macrothink Institute, 2019) Odhiambo, Nicodemus Osoro; Obade, Paul; Gathuru, Gladys
Land use and land cover change as a result of human-induced transitions is a major environmental challenge in Lake Victoria Basin. The study adopted a mixed-method consisting of remote sensing and GIS-based analysis, key informant interviews, and household survey consisting of 384 households to asses Land Use and Land Cover Dynamics and associated human-induced transformations in Ombeyi wetland. The study aimed at generating a characterized area estimate of Ombeyi wetlands land use and land cover change schema for the study period (1990-2017), and examining the spatial and temporal characteristics of anthropogenic impacts and their relationship with land use and land cover change in Ombeyi wetland. The gis-based analysis revealed that built-up area/settlements and agricultural lands extensively increased in area at the expense of wetland vegetation. Key informants attributed the changes to population increase (29.2%) and an associated demand for land and natural resources as the major driving forces for the changes. Analysis of household-survey results validated the observed patterns during the remotely sensed data analysis phase of the research, as 90.1% (n=384) of the respondents reported to own land within the wetland through inheritance. 92.2% of the respondents are farmers practicing farming in the wetland with 72.4% of the same respondents attaining primary level education and below. Poverty and education levels were significant factors in influencing unsustainable land use and land cover changes observed in this study. The present state of land cover and its dynamics have had negative impacts on the riparian rural livelihoods and natural resource management.
Assessing perceived impacts of climate change and how small scale farmers adapt in N in North Kinangop Location, Kenya.
(2014) Njenga, N.W.; Mucheru-Muna, M.; Muriuki, J.N.
Climate variability and change has been considered to be posing the greatest threat to agriculture and food security in many of the poor, agriculture-based countries in Africa. In recognition of this, an assessment of climate change impacts on small-scale farmers was conducted in Nyandarua South District to assess the impacts of climate variability and change on the small-scale farmers in the area. The area is nationally known as a high agricultural potential area producing all year round horticulture produce. Data was obtained through administration of questionnaires, observation and focused group discussions. Through systematic random sampling the researcher administered 375 households’ questionnaires representing 10% of the total households in the study area. Descriptive statistics (frequency, mean, percentages) and inferential statistics (chi square) were used to produce associations between variables assessed. The results indicate that small-scale farmers in North Kinangop Division are struggling with impacts of climate variability. According to analysis, there was a strong association between perceived rainfall intensity variations and impacts on small-scale farmers in North Kinangop (X2 = 15.411, P =0.05) and strong association between rainfall distribution and loss of crops and reduced freshwater (X2 = 41.226, P=0.001). Extreme climatic events occurrences had a strong association with impacts on small-scale farmers (X2 = 32.692, P = 0.001). It can therefore be concluded that small-scale farmers have perceived climate variability to be impacting heavily on their agricultural activities as rainfall intensities, reliability and distribution continue to vary in time and space. Other meteorological extreme events (droughts and frost) have been observed to intensify in the area with consequent impacts on crop production. This paper therefore recommends more capacity building programmes to be initiated in the area to enhance awareness of climate variation and change, impacts and adaptation measures to enhance the farmers’ resilience.
Assessing the Uptake of Modern Kiln Technology in Mutomo, Kitui County, Kenya
(Finlogy, 2017) Kioli, John; Wemali, Evelyn; Ngare, Innocent
The demand for energy on developing nations has increased in the past three decades propelled by population growth. This has led to more biomass energy consumption and use in the households. For this study, we assess factors that will propagate better uptake of modern kilns that are environmental friendly and minimal on waste of wood fuel for the production of charcoal in Mutomo. Methodology of the study employed the following sampling techniques: random sampling; stratified sampling and purposive sampling during the survey. The sample size was 255. The methods of data collection used were observation and questionnaires. Both qualitative and quantitative data was obtained. Qualitative data was analysed through content and thematic analysis where the information received from the respondents were captured as were stated. The discussed findings also indicate the perceptions towards the uptake of modern charcoal producing kilns. Further, we analyze challenges of transitioning from traditional earth kilns to modern technology kilns. We conclude that, equitable use of environmental resources depend on better technologies that facilitate sustainability. Therefore the efficiency and economical characteristics of modern kilns play an important role in their adoption because they help in getting high quality charcoal such that the traders are able to get maximum returns. For the socioeconomic wellbeing of charcoal producers, modern kilns are economical and profit generating thus maintaining the forest cover unlike tradition kilns that degrades it. The formation of charcoal processing associations is the main way of encouraging the use of modern charcoal burning kilns other than the sensitization of the public on the benefits of the use of modern charcoal burning kilns.
Assessment of Decay Coefficients of Allochthonous Litter for Sustainable Riparian Forage Agriculture and Environmental Monitoring: A Study in River Nyangores, Kenya
(2016-06) Ochieng, J.; Kitur, C. E.; Obade, P. T.
Research on decay profiles of grass detritus in lotic systems has received little attention in preceding years. An investigation was conducted on in-situ processing coefficients for three dominant forage species grown by farmers along the banks of River Nyangores in 2013. The objectives of the study were; (i) to determine in-situ processing coefficients for Pennisetum purpureum, Panicum coloratum and Chloris gayana, and (ii) to estimate detrital total phosphorus trends during incubation. It was hypothesized that no significant differences existed among the decay rates of the three grass species. A total of 186 leaf packs were deployed in River Nyangores at upstream and downstream sections separated by Bomet urban settlement for ten weeks, with a twoweek withdrawal interval. Temperature normalized decay rates were estimated using an aquatic decay model. Total phosphorus was analyzed using the molybdate-calorimetric procedure with ultraviolet spectrophotometry. Data was analyzed using XLSTAT-2014 computer program. The in-situ decay coefficients ranged from 6.70795 x 10-4 dd-1 to 9.12355 x 10-4 dd-1. Covariance analysis (p<0.05) indicated significant differences for the decay rates among the three species, with higher in-situ processing coefficients recorded downstream than upstream for all the grasses. Litter phosphorus showed positive Pearson correlation with decay rates though not significant (p>0.05). During incubation, detrital phosphorus build-up was lower upstream at 6.4% than downstream at 13.8%. Highest decay rate was recorded for Chloris gayana hence it appears to be the most agro-ecologically sustainable as a riparian forage for River Nyangores. Bomet urban settlement seemingly contributes to shifts in ecological functioning of the river. Keywords : Agro-ecological, Aquatic, Decay, Ecological monitoring, Riparian, Sustainable.
Assessment of the Impact of the Woodcarving Industry on the Environment: A Study of Wamunyu Location, Mwala District, Kenya
(2014) Mutinda, Jane
The wood carving industry in Kenya is highly dependent on indigenous tree species. These hardwood species have other competing uses too: they are preferred for ornate and construction. In construction, they are used as timber for furniture, flooring, and civil works. Over the years, there has been selective harvesting of these preferred tree species, leading to a decline and, locally, to a collapse of the tree population and contribution to the degradation of forests and woodlands. These species take between 100-150 years to mature. The study was on woodcarving handicraft among the Kamba community in Wamunyu location of Mwala District in Kenya. It examined the extent to which the practice has impacted on the raw materials used in the production of the craft. A total of 100 woodcarvers participated in the survey. These were purposively sampled for the reason that in each location, the target respondents were organised into a major association. In Wamunyu the major association is Wamunyu Cooperative Society. Other study respondents included cooperative officials and, programme managers of local non-governmental organisations. Questionnaires, in-depth interview guides, focus group discussions, observation and photography were used in collecting data which revealed certain significant aspects of the handicraft. Wood carving is a major informal industry in Wamunyu. It is a source of livelihood for many families. However, it has been practiced to the detriment of the environment. Witnessed is a complete disappearance of some indigenous trees originally used in the industry due to inactive foresight in replenishing the resource base. Most carvers are blind to environmental concern but monetary gain. Revealed as well, resident NGOs have very little to do with the handicraft industries despite the significance of the crafts as major income earners. Admittedly, the findings suggest a need for woodcarvers to carryout their trade in a sustainable way. Required are afforestation and reforestation programmes and, as relates to leftovers from the craft, adaptation of good waste management practices. For example, use of cut-offs in carving smaller items and making of compost manure rather than setting ablaze the resultant leftovers. The cooperative societies should be in the forefront of ensuring that sustainable wood carving is done. There is need for urgent extensive mobilisation of all stakeholders to start nurseries and plantations with the sole purpose to grow raw materials for use by the craft. Hence conservation education would come in handy in promoting sustainable woodcarving. Suggested as well is a need for resident non-governmental organisations to expand their activities and train and empower the woodcarvers in aspects such as resource conservation, water harvesting techniques and, diversification of income generating activities.
Assessment of Yatta Canal Water Quality for Irrigation, Machakos County, Kenya
(OMICS International, 2017) Manohar, S.; Mang’oka, J.M.; Ndunda, E.; Gathuru, G.
Water is one of the most important global requirements for every activity in life but if it is polluted/contaminated, then it creates direct problems of alkalinity/salinity/toxicity through irrigation to agricultural farms and affects on the quality and nutritional value of cultivated crops. Water quality of Yatta Canal was studied from January to December, 2015 within Machakos County of Kenya. Twenty sampling stations were selected at an interval of 1 km along this canal and water samples were collected once in a month during the wet and dry seasons to monitor its suitability for irrigation. Annual average values of temperature, pH, total dissolved solids, turbidity, dissolved oxygen, and electrical conductivity show significant (P<0.05) seasonal variation. Annual average chemical concentrations of the water during wet and dry seasons are; Nitrates 13.1 ± 0.47 mg/l vs 4.8 ± 0.13 mg/l; Phosphates 0.02 ± 0.001 mg/l vs 0.02 ± 0.001 mg/l; Potassium 3.8 ± 0.098 mg/l vs 2.8 ± 0.031 mg/l; Sulphates 10.7 ± 0.31 mg/l vs 7.2 ± 0.25 mg/l; Bicarbonates 46.9 ± 1.20 mg/l vs 79.9 ± 2.06 mg/l; Chlorides 14.3 ± 0.59 mg/l vs 2.0 ± 0.10 mg/l; Sodium 14.7 ± 0.436 mg/l vs 17.7 ± 0.200 mg/l; Calcium 5.9 ± 0.124 mg/l vs 8.1 ± 0.058 mg/l; Magnesium 2.2 ± 0.020 mg/l vs 2.9 ± 0.029 mg/l, Sodium Adsorption Ratio 1.30 ± 0.030 me/l vs 1.35 ± 0.020 me/l and Iron 0.49 ± 0.007 mg/l vs 0.64 ± 0.041 mg/l respectively. These chemical parameters also show significant (P<0.05) seasonal variation. Most of the physical and chemical levels are within the permissible limits as recommended by FAO and also by Kenya’s National Environment Management Authority with the exception of turbidity (100.2 NTU) and nitrate concentration (13.1 mg/l) only during the wet season. Based on the results, the canal water is safe for irrigation during dry season
Challenges and Opportunities of Participatory Management of Upland Wetland in Kiambu County, Kenya
(SIB, 2020) Kinyariro, Mwaura Samuel; Njuguna, Steven Gichuki; Macharia, Geoffrey
Kinyariro MS, Njuguna SG, Macharia G. 2020. Challenges and opportunities of participatory management of Upland Wetland in Kiambu county, Kenya. Bonorowo Wetlands 10: 78-91. Wetlands are continuously degraded through agricultural activities, pollution, and settlements. For example, in the Lari sub-district, increased population pressure decreased soil fertility, unreliable rainfall, and the search for food security forced farmers to encroach on the seemingly idle Upland Wetlands. Opportunities for wetland conservation lie in participatory approaches applied locally to conserve this vital natural resource. The main water of the Ruiru river comes from the Upland Wetlands harvested by the Nairobi Water and Waste Company in the Githunguri sub-district at the Ruiru dam. This research is critical because the water company does not have in-depth information about its catchment area, which leads to encroachment and ultimately rationing of water in the city of Nairobi. This study aims to document the causes of wetland degradation in the highlands, assess the level of community participation, and determine the level of awareness of the importance of wetlands and the possible contribution of farmer involvement in catchment management. The sampling method used to select the research unit was stratified and random sampling where farmers and Ruiru dam workers were given a questionnaire. Purposive sampling was used to determine the WARMA manager, WRUA officer, and six older people interviewed. 40 farmers from the Lari 107 settlement scheme where the wetlands are located, and four workers of the Ruiru dam were given questionnaires. Data analysis was performed using the Chi-square package computer, T-test, and SPSS. Percentages for qualitative data are presented using tables, bar charts, and pie charts. The wetland mapping was carried out using GIS and Google Earth. The study results found that the total land cover of upland rice fields was 129.6 Ha after deducting 105.4. Ha for the last thirty years due to encroachment. The study revealed that 65% of respondents had lived in the area for more than 20 years. Farmers drain wetlands primarily for food supply (50%) to generate income (25%), while 10% control waterborne diseases. Participation rates are negligible, with only 2.5% of respondents participating in wetland conservation. Community-based conservation groups like WRUA still lack in this area. Environmental impacts include loss of biodiversity, destruction of ornithological habitat, and loss of hydro plant species. Social effects include outbreaks of waterborne diseases such as typhoid, water pollution, and weak community conservation infrastructure. However, there is a chance for community involvement, where the majority of the population is ready to carry out conservation (X2 = 0.127, p = 0.001). The formation of community-based conservation groups such as the Water Resources Users Association, the Association of Riverland Owners, and the Watershed Advisory Committee was proposed as the primary solution. Devolution of water resources is also proposed to ensure local people benefit from selling water to city residents. Such efforts would provide an adequate water supply to Nairobi and the surrounding satellite cities
Climate Change Impacts on Small Scale Farmers in North Kinangop Location, Kenya
(The International Journal of Climate Change: Impacts and Responses, 2014) Njenga, N. W.; Mucheru-Muna, M.; Muriuki, J.N.
Climate variability and change has been considered to be posing the greatest threat to agriculture and food security in many of the poor, agriculture - based countries in Africa. In recognition of t his, an assessment of climate change impacts on small - scale farmers was conducted in Nyandarua South District to assess the impacts of climate variability and change on the small - scale farmers in the area. The area is nationally known as a high agricultura l potential area producing all year round horticulture produce. Data was obtained through administration of questionnaires, observation and focused group discussions. Through systematic random sampling the researcher administered 375 households’ questionna ires representing 10% of the total households in the study area. Descriptive statistics (frequency, mean, percentages) and inferential statistics (chi square) were used to produce associations between variables assessed. The results indicate that small - sca le farmers in North Kinangop Division are struggling with impacts of climate variability. According to analysis, there was a strong association between perceived rainfall intensity variations and impacts on small - scale farmers in North Kinangop (X2 = 15.41 1, P =0.05) and strong association between rainfall distribution and loss of crops and reduced freshwater (X2 = 41.226, P=0.001). Extreme climatic events occurrences had a strong association with impacts on small - scale farmers (X2 = 32.692, P = 0.001). It can therefore be concluded that small - scale farmers have perceived climate variability to be impacting heavily on their agricultural activities as rainfall intensities, reliability and distribution continue to vary in time and space. Other meteorological e xtreme events (droughts and frost) have been observed to intensify in the area with consequent impacts on crop production. This paper therefore recommends more capacity building programmes to be initiated in the area to enhance awareness of climate variati on and change, impacts and adaptation measures to enhance the farmers’ resilience
Combining Manure with Mineral N Fertilizer Maintains Maize Yields: Evidence from Four Long-Term Experiments in Kenya
(Elsevier, 2023) Laub, Moritz; Corbeels, Marc; Ndungu, Samuel Mathu; Mucheru-Muna, Monicah Wanjiku; Mugendi, Daniel; Necpalova, Magdalena; De Broek, Marijn Van; Waswa, Wycliffe; Vanlauwe, Bernard; Six, Johan
Context: Crop productivity in sub-Saharan Africa cannot be substantially improved without simultaneously addressing short-term crop nutrient demand and long-term soil fertility. Integrated soil fertility management tackles both by the combined application of mineral fertilizers and organic resource inputs but few studies examined its‘ long-term effectiveness. Objective: To address this knowledge gap, this study analysed maize yield trends in four long-term (31–37 cropping seasons) field experiments in Kenya with contrasting soil textures and under different climates. Methods: All sites had two maize cropping seasons per year, received a base P and K fertilization and tested combinations of organic resource addition (1.2 and 4 t C ha-1 yr-1 ranging from farmyard manure, to high-quality Tithonia diversifolia and Calliandra calothyrsus material to low-quality saw dust), combined with (+N) and without (-N) mineral N fertilizer (120 kg N ha-1 season-1). General maize yield trends across sites and site specific trends were analyzed. Results: Across sites, the no-input control experienced significant average maize yield reductions of 50 kg ha-1 yr-1 over the study period. In contrast, the treatment with farmyard manure +N maintained yields at both 1.2 and 4 t C ha-1 yr-1. High initial yields following additions of Tithonia and Calliandra, reduced over time. Assessment by site showed site specificity of maize yields and yield trends. For example, the two climatically favorable sites in western Kenya experienced yield gains with high quality organic resources at 4 t C ha-1 yr-1, leading to yields of up to 8 t ha-1 per season, while sites in central Kenya experienced yield losses, leading to 3.5 t ha-1 per season. Yield site specificity for ± mineral N treatments was stonger than for organic resource treatments, e.g. the clayey site in central Kenya in the end showed no yield differences between ± N, except for the 1.2 t C ha-1 yr-1 farmyard manure treatment. Yet, farmyard manure plus mineral N consistently achieved highest yields of all organic resource treatments at all sites and farmyard manure addition at 1.2 t C ha-1 yr-1 (about 5 t dry matter) was the most N-efficient treatment. Conclusions: At realistic application rates, maize yield in integrated soil fertility management is best sustained by a combined application of farmyard manure and mineral N. Implications: Mixed crop-livestock systems and a combined manure and mineral N application are key ingredients for sustained productivity of smallholder systems in sub-Saharan Africa.

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