RP-School of Environmental Studies

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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
Adaptation Mechanisms and Coping Strategies to the Effects of Climate Variability on Maize Yield with Focus on Matungulu West, Machakos County Kenya
(Finlogy, 2017) Mabonga, E.S.; Manguriu, D.G.; Kerich, R.; Nakokonya, G.M.
Climate variability is a phenomenal challenge to the citizens of the globe. It is noticeable from many documented studies that climate variability is taking place at an alarming rate. The globe has been experiencing an increase in temperature of approximately ≈ 0.20 C after every ten years for the last three decades. It is also established that rainfall increased significantly from 1900 to the 1950 then dropped from 1970 to present. The total sum of such extremes is a terribly affected livelihood in particular those living below the dollar. However, farmers in Matungulu West, in Machakos County Kenya have established their own measures and strategies to address the effects posed by climate variability. That informed the main objective of this study which was To determine adaptation measures and coping strategies being practiced by households in Matungulu West in Machakos County Kenya in addressing climate variability. A structured questionnaire which was developed and pre-tested was used to interview 380 randomly selected household heads to elicit information. Findings of the study indicate that most (52.2%) of the farmers have reduced or spread risks by replanting with early maturing maize, (26.4%) staggering planting dates, (2.9%) changing crops when replanting, (6.6%) grazing of failed parcels of land and (11.9%) carrying out varietal selection of stress resistant to suit the prevailing conditions. It was established further that (64.8%) of the respondents preferred early sowing as an adaptation option while (1.4%) indicated that they were practicing irrigation farming to combat climate variability. This study made a conclusion that there is a broad range of contrasting diversification strategies employed between different types of households headed by either females or males with the ownership or lack of ownership of cattle being a key factor that cuts across household types and which provided considerable additional flexibility.
Adaptations of Environmental Sound Practices for Industrial Parks in Kenya: Lessons from the Magana Industrial Park, Kenya
(Academia.edu, 2013) Maina, L.; Kirui, A.; Karagu, N. M.
The effects of poor natural resource management are being demonstrated dramatically in many developing countries like Kenya. Inappropriate agricultural practices in high and medium potential areas have accelerated deforestation and soil erosion. The intense farming in such areas has involved heavy use of agro-chemicals, which has resulted in the pollution of rivers, lakes and other wetlands. Magana Holdings Limited considered the nucleus of Magana Industrial Park was established in 1994 by the proprietor in the twin response to his entrepreneurial instinct and implicitly to the government policy for stimulating development in rural areas through the implementation of an industrialization strategy. Often striking a balance between production and ecological integrity around such agro-enterprises is complex. The study investigated the environmental best practices being implemented by Magana Holdings Limited within its flagship floricultural business with a view to learning replicable lessons. It is apparent that Magana Floricutural Enterprises adheres to a raft of positive environmental practices including integrated pest management, safe use and storage of agrochemicals, water conservation through recycling programmes, green manure preparation and application among others. The continuous surveillance of environmental conditions and strict adherence to both national and international standards has had a positive effect on the local environmental outlook.
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.
Agronomic and Financial Benefits of Phosphate Rock Use in Acidic Soils of Upper Eastern Kenya
(SSRN, 2021-07) Ndeleko-Barasa, Emily Mwake; Mucheru-Muna, Monicah; Ngetich, Felix Kipchirchir
A major constraint to crop production in Sub-Saharan Africa is nutrient deficiency, especially phosphorus deficiency. Phosphorus plays a crucial role in photosynthesis but is usually deficient in acidic soils since it is converted to less available forms, affecting crop yields. There is a need to improve phosphorus availability to crops for maximum production. This study assessed the impact of phosphate rock fertilizer application on maize yields, soil chemical composition, and cost-effectiveness in Tharaka Nithi County, Upper Eastern Kenya. We set a field experiment in a randomized complete block design (RCBD) during long rains (SR2017) and Short rains (LR2018) seasons. The treatments were phosphate rock + manure, Tithonia diversifolia + phosphate rock, Calcium Ammonium Nitrate (CAN) + Triple Superphosphate (TSP), and a control. Soil samples were collected at a depth of 0-20 cm before and at the end of the experiment for pH, P-sorption, and other soil nutrients determinations. Other auxiliary data collected included labor and input costs besides output prices. The CAN+TSP treatment had significantly higher grain yields, while phosphate rock on its own had the second-lowest than the control treatment (p<0.05). We also observed a similar trend in the stover yields. Phosphate rock combined with either manure or Tithonia diversifolia led to a significant (p<0.05) increase in the phosphorous levels. Sole application of organics increased soil sodium and calcium while iron levels decreased. Other than the control, all treatments significantly lowered the p-sorption levels. However, CAN+TSP had the highest p-sorption while Tithonia diversifolia had the lowest. During the LR2018 season, a break-even point was arrived at with all the treatments, and the net benefit was significantly higher at P<0.05. Conclusively, the use of phosphate rock, either solely or in combination with organic elements, was found to improve yields, soil chemical composition, P-sorption, and very cost-effective.
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 Aflatoxin Levels in Broiler Chicken Feed from Selected Farms in Nairobi City County, Kenya
(Springer Nature Switzerland, 2023) Chepkosgei, Kirinyet Ruth; Njogu, Warutere Peterson; Purity, Nguhiu; Ojola, Patroba C; Joel, Kirinyet
Aflatoxin levels in animal feed should be observed from the farm to the table to ensure the safety of the feed to animals and humans. The contamination of cereals and other agricultural supplies used in animal feed production could happen in the farm in the pre-harvest phase or in the post-harvest phase. The study sought to determine Aflatoxin levels in broiler feed from selected farms in Nairobi City County. A total of 42 feed samples were collected. Samples were analyzed using the LCMS/MS technique. Results from the study show that Aflatoxin levels in broiler starter were; B1(17.26±3.07 ppb), B2 (2.44±0.84 ppb), G1 (8.87±2.41 ppb), G2 (0.9±0.44 ppb) and Total AF (29.47±6.13 ppb). Aflatoxin levels in broiler finisher were B1 (17.17±3.09 ppb), B2 (2.68±1.18 ppb), G1 (9.25±2.7 ppb), G2 (1±0.45 ppb) and Total AF (30.1±6.88 ppb). Results from analysis of feed samples showed that AFB1 levels in both broiler starter and broiler finisher were above the KEBS limit but were below the EAC, EU and WHO/FAO limit. Total Aflatoxin levels were above the KEBS limit but below the EAC limit. There is need to enhance the capacity of feed surveillance and monitoring in the country through various laboratory analysis techniques among various agencies in the feed value chain to ensure feed safety
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.
Analysis of the Relationship between Land Surface Temperature and Vegetation and Built-Up Indices in Upper-Hill, Nairobi
(Scientific Research Publishing, 2018) Mwangi, Patricia Wanjiku; Karanja, Faith Njoki; Kamau, Peter Kariuki
Designing “liveable” cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) effect occurs when there is a difference in temperature between rural and urban areas. In urban areas, impervious surfaces absorb heat during the day and release it at night, making urban areas warmer compared to rural areas which cool faster at night. This Urban Heat Island effect is particularly noticeable at night. Noticeable negative effects of Urban Heat Islands include health problems, air pollution, water shortages and higher energy requirements. The main objective of this research paper was to analyze the spatial and temporal relationship between Land Surface Temperature (LST) and Normalized Density Vegetation Index (NDVI) and Built-Up Density Index (BDI ) in Upper-Hill, Nairobi Kenya. The changes in land cover would be represented by analyzing the two indices NDVI and BDI . Results showed the greatest increase in temperature within Upper-Hill of up to 3.96˚C between the years 2015 and 2017. There was also an increase in impervious surfaces as indicated by NDVI and BDI within Upper-Hill and its surroundings. The linear regression results showed a negative correlation between LST and NDVI and a positive correlation with BDI , which is a better predictor of Land Surface Temperature than NDVI . Data sets were analyzed from Landsat imagery for the periods 1987, 2002, 2015 and 2017 to determine changes in land surface temperatures over a 30 year period and it’s relation to land cover changes using indices. Visual comparisons between Temperature differences between the years revealed that temperatures decreased around the urban areas. Minimum and maximum temperatures showed an increase of 1.6˚C and 3.65˚C respectively between 1987 and 2017. The comparisons between LST, NDVI and BDI show the results to be significantly different. The use of NDVI and BDI to study changes in land cover due to urbanization, reduces the time taken to manually classify moderate resolution satellite imagery.
Analysis of woodfuel supply and demand balance in Kiambu, Thika and Maragwa districts in central Kenya
(Journal of Horticulture and Forestry, 2012-04-01) Githiomi, J. K.; Kung’u, J.B.; Mugendi, D. N.
This study was undertaken in Kiambu, Thika and Maragwa districts of Central Kenya and it aimed at developing micro-level wood energy plan that would act as a case study for future decentralized wood energy plans in Kenya. Primary data was collected from households, service/production institutions comprising of factories/industries, schools, restaurants, hospitals and prisons using structured questionnaires. The study established a deficit between supply and demand balance of -41.7, -45.6 and -50.1% of woodfuel in 2006 for Kiambu, Thika and Maragwa districts respectively. The strategies suggested in micro-level wood energy plans to curb these deficits include allocation of gazette plantation forest to fuel wood production, increase of improved stove technology, increase of on-farm tree land area and use of alternative energy sources. The combination of all these strategies gave a surplus of 22,903, 46,947 and 32,409 tons of woodfuel in Kiambu, Thika and Maragwa districts, respectively by 2018. The study recommended implementation of the identified strategies aimed at reducing the huge deficit between supply and demand, enhancing inter-institutional collaboration in all sectors related to wood energy development, developing clear policies to guide charcoal and firewood production and marketing and having regular wood energy surveys
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.
Application of GIS and remote sensing techniques in frost risk mapping for mitigating agricultural losses in the Aberdare ecosystem, Kenya
(Taylor & Francis, 2014-10-30) Onywere, S. M.; Kotikot, Susan Malaso
Frost is a perennial agricultural hazard that normally causes crop damage leading to huge agricultural losses within the Kenyan highlands; aggravated by inadequate information on frost. This research mapped frost hotspots within the Aberdare and Mount Kenya regions and identified the extent of arable land under frost risk while establishing the trend of minimum temperature occurrences between the years 2000 and 2013. Minimum temperature values were extracted from daily Moderate Resolution Imaging Spectroradiometer land surface temperature data-sets, and frost risk categorized into very severe frost (<250 K), severe frost (250–260 K), moderate frost (260–270 K), minor frost (270–280 K) and areas of no frost. Concentration of frost (<273 K) was mapped within regions above 1500 m asl and occasional occurrences within valleys lower than this altitude with recurrent occurrences in the months of April, May, July, August and November. Elevation, land surface convexity and humidity were found to influence frost occurrence. Improved agricultural practice to mitigate against losses is recommended.
Application of GIS and remote sensing to frost risk mapping for improved agricultural productivity in the Aberdare region, kenya
(2014-05-02) Kotikot, Susan Malaso; Onywere, S. M.
Frost is a perennial agricultural hazard within the Aberdares and Mt. Kenya regions that normally causes crop damage leading to huge agricultural losses. This is aggravated by inadequate information on frost risk to cushion investors and farmers against losses. This research maps frost hotspots within the Aberdare and Mt. Kenya regions, while identifying the extent of arable land at risk of frost damage so as to establish the implication of frost occurrence on food security and economic growth. It also establishes the trend of minimum temperature occurrences between the years 2000 to 2013 in order to identify any existing patterns in frost occurrences. Minimum temperature values were extracted from monthly MODIS LST datasets using ENVI 4.7 software and frost risk categorized into very severe frost (<250K), severe frost (250-260K), moderate frost (260-270K), minor frost pockets (270-280K) and areas of no frost (>280K) using ENVI 4.7 decision tree classifiers. Frost was found to concentrate around the Aberdares and Mt. Kenya regions with temperatures below 270K concentrating in regions above 1500m asl. Elevation, land surface convexity as well as high rainfall are some of the factors that were found to influence its occurrence. Time series analysis of minimum monthly temperatures extracted from MODIS LST data in ArcGIS showed recurrent patterns of minimum temperature occurrences in the months of April, May, July, August and November. The study proposes adoption of resilient crop cultivars, use of manual protective measures such as sprinkler irrigation, artificial wind breeze induction and use of green houses, crop rotation based on growth durations as well as planting site selection based on crop susceptibility as well as land surface curvature in order to mitigate the losses and ensure maximum crop production.

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