RP-Department of Geography

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Land and Population Problems in Kajiado and Narok, Kenya
(Cambridge University Press, 1984-03) Sindiga, I.
The physical appearance of Africa's marginal semi-arid lands shows evidence of eroding hillsides, denuded plains, large erosion shelves, and deep sheer-sided gulleys. These features manifest an imbalance between humans and the resources which support them or what some scholars have termed rural population pressure (Anzagi and Bernard, 1977; Steel, 1970). A decade ago, an International Labor Office mission to Kenya (1972: 405, hereafter ILO) noted that surface soil degradation and erosion in marginal semi-arid areas were chronic. Other symptoms of the physical destruction of the land included the drying up of streams, cultivating on river banks leading to silting of streams and dams, unchecked gullying of cultivated slopes, and sheet erosion following bad grazing practices. More recently, the World Bank (1980: 53) noted that increasing population growth in the drier areas of Kenya has led to a pressure exceeding the carrying capacity of the land, which in turn has led to lower income per capita, and even to famine. In general Kenya's rangelands are densely populated relative to pastoral areas in other African countries (von Kaufmann, 1976: 255). The government itself (Kenya, 1979a: 211) notes the urgency of dealing with social problems related to the rapid population expansion in medium and low potential areas of the country where crop production is feasible but very risky.
Evaluation of agrometeorological indices as maize yield predictors in a high rainfall Kenyan environment
(East African Agricultural and Forestry Journal, 1990) Shisanya, C.A.; Coulson, C. L.; Stigter, C. J.
Maize is the most important food crop in Kenya and occupies more than 25% of the total land area in many high rainfall areas of the country. Investigations were carried out to test which agrometeorological crop yield forecasting models would come out with accurate predictions of maize yields. Two FAO methods developed by Frere and Popov (FAO 1986) and by Doorenbos and Kassam (1979) were used in predicting maize yields of variety H625 in Kakamega district. Results are discussed
A Review of Methods for Estimating Evapotranspiration
(Kluwer Academic Publishers, 1991) Kairu, E. N.
The problems which characterize the study of evapotranspiration are briefly discussed. Different models which have been used for estimating evapotranspiration are reviewed. They include the eddy correlation model, mass transport model, aerodynamic model, Penman-resistance model and the energy balance model. The utilization of remote sensing for regional evapotranspiration estimation is discussed at length with case studies cited from USA, France, Germany and Kenya.
Day-time Effects of Urbanization on Relative Humidity and Vapour Pressure in a Tropical City
(Springer-Verlag, 1991) Adebayo, Y. R.
“Heat island” in a Humid Tropical City and its Relationship with Potential Evaporation
(Springer-Verlag, 1991) Adebayo, Y. R.
Responding to population pressure in the rural Kenya
(Kluwer Academic Publishers, 1993-08) Ogutu, Z. A.
This paper reviews different historical and contemporary factors responsible for population pressure in the rural Kenya. It is argued that the process is not new, having its roots in the colonial administration. Cultural backgrounds, the economic setting of the rural population and the large moisture stricken areas are responsible for population pressure in the postindependence era. Different ways of mitigating population pressure such as (i) encouraging land use options that least stress the human ecology and natural environment; (ii) reducing the number of people and; (iii) diversifying sources of income to supplement earnings from agriculture so as to reduce direct dependence on land are discussed. Constraints with these strategies, particularly socio-economic factors such as land inheritance and the need for many children, are also discussed with a view to establishing the way out to sustainable development.
Field Assessment of Flood Event Suspended Sediment Transport from Ephemeral Streams in the Tropical Semi-Arid Catchments.
(PubMed, 1995-03) Ondieki, C. M.
An assessment of suspended sediment transport was carried out in a number of semiarid catchments during flood events in order to quantify the degradation rates. In order to quantify these, a systematic sampling procedure of the episodic flood events was proposed for representative catchments. The procedure allows for an integration over the whole run-off episode using both the rising and falling limbs of the run-off hydrograph to compute the sediment quantities for each individual flood event.Higher sediment concentrations occurred in the rising limb than those at the recession for any stage of flow. The maximum suspended sediment concentration was observed at the peak of the flood hydrograph. An integration of the sediment concentration over its duration gave the total sediment yield from the flood event. For the ephemeral channels, only a small number of flood events were observed over a three-year experimental period each with a duration of the order of 3-6 h. It is notable that high sediment loads were associated with high flow volumes which were effectively the result of the catchment characteristics and incident rainfall causing the flood events in the respective catchments. A large percentage of the annual sediment yield from a catchment is transported by the ephemeral streams during a small number of flood events. The correct determination of the total sediment yield from any of the flood events depends entirely on the accuracy of the measurements.The understanding of run-off and sediment loss for the representative catchments aims at assisting planning, management and control of water and land resources for sustainable development in the semi-arid parts of the tropics. The sediment rates reveal the degradation of catchments which have repercussions on the crop and pasture production and this has a bearing on the soil and water conservation programmes in the delicate ecological balance of the semi-arid areas. Further, these rates will determine the lifespan of the reservoirs planned for the dry river valleys (ephemeral streams) and existing ones which serve livestock and domestic needs. These occasionally will require costly rehabilitation and scooping to increase effective storage unless conservation measures are taken, and these measures are bound to vary from place to place as per the representative catchments output.
Multivariate analysis of plant communities in the Narok district, Kenya: The influence of environmental factors and human disturbance
(Kluwer Academic Publishers, 1996) Ogutu, Z. A.
Species type in 42 samples was examined using ordination analysis to establish whether the vegetation pattern displays gradation due to environmental factors, and whether the pattern was being altered by human disturbance. The analysis displayed two patterns. First, the ordination on axis 1 demonstrated vegetation gradation from xeric communities on the plains to humid forests on the highland. This pattern is explained on the basis of moisture and nutrient variations. Vegetation vectors based on species presence-absence were correlated with average rainfall, carbon, nitrogen and zinc. The second was separation of disturbed and undisturbed forest and bushland site categories on axis 2 of the ordination space. This pattern suggests that disturbance response is interactive with moisture so that only in moist communities does a significant vegetation response to disturbance occur.
Modelling the impact of land abandonment on runoff and soil erosion in a semi-arid catchment.
(University of London, 1997) Obando, Joy Apiyo
The overall aim of this research is to evaluate the dynamic interactions between soil moisture, vegetation and erosion of abandoned land in a semi-arid setting within the context of changing climate, with a view to establishing the appropriate land use practices. This is crucial issue in semi-arid Spain, where land abandonment has been increasing in the last 40 years as a result of aridity and changing socio-economic activities. The research adopts a multi-faceted approach to investigate the response of vegetation and the hydrology for varying rates, patterns and percentages of abandonment. This is done by integrating field measurements from a semi-arid catchment with computer modelling. Field measurements of vegetation characteristics, soil factors, slope aspects, surface characteristics and other physical variables have been collected from abandoned land in Rambla del Chortal, Murcia in South East Spain. The key parameters for the soil hydrology model were identified using rainfall simulation experiments in the same catchment. A simple single layer soil model has been developed to simulate these interactions and to explore the impacts of land abandonment on biomass production, runoff generation and sediment yield. The basis of the model is the continuity equation described in the form of a simple water balance equation. The main assumption of the model is that water is the limiting factor to plant productivity in semi-arid areas. The soil hydrology is influenced by interception, infiltration, drainage and evaporation. Plant growth is estimated as dry matter accumulation using the actual evapotranspiration rates and a water use efficiency. A regular gridded Digital Elevation Model (DEM) of the catchment has been used for the routing of the overland flow generated, and for computation of spatial erosion rates for varying spatial patterns of abandonment. The model has low data requirements and is designed in a flexible manner to allow modifications to suit the available data. The results indicate that vegetation regeneration in the catchment following abandonment depends largely on the rainfall amount, the timing of abandonment and the percentage and rate of abandonment. The simulated vegetation recovery curve has the characteristic logistic form, and is consistent with field measurements in Rambla del Chortal. The impact of abandonment on runoff generation and sediment yield in the catchment depends largely on the character and rate of abandonment as well as the rainfall characteristics. The runoff and sediment yield simulated by the model generally decreases with abandonment since the vegetation cover increases over time. Large magnitude events tend to produce high sediment irrespective of the vegetation cover in the catchment. For dry periods, correspondingly low sediment yield is produced implying thatincreasing aridity will not necessarily lead to higher erosion rates. A positive relationship exists between the annual rainfall amount and the modelled sediment yield.
Potential of Episodic Flows in Some Four Representative Non-perennial River Flow Catchments in Semi arid Laikipia District, Kenya
(Kluwer Academic Publishers, 1997) Ondieki, C. M.
The purpose of this study was to establish the water resources of thenon-perennial streams in providing supplementary water needs inLaikipia district. This district has undergone remarkable land usechanges resulting in water use stress of perennial river abstractions andgroundwater exploitation in the semi arid environment. Over a three year period extending from January 1989 to December1991, hydrological variables were monitored in four non-perennial flowcatchments within the district. These catchments have been shown tohave potential of about 8000 m3/km2/year except forlong dry spells during the observation period and high sediment lossesand evaporation rates calling for proper conservation measures in orderto exploit productively the water resources potential of such catchments
Conflicts over resources: Saiwa Swamp National Park (Kenya) and its environs
(Kluwer Academic Publishers, 1997) Ogutu, Z. A.
This paper examines conflicts in Saiwa Swamp National Park and adjacent households. The conflicts centre on poaching of park resources and destruction of park ecology on the one hard and, the spread of diseases, crop damage by wildlife and loss of land by adjacent households on the other. The conflicts are primarily due to socio-economic constraints in park-adjacent areas following government policies which are irresponsive to the livelihood needs of the local community. To fill up the missing link between policy and practice, participatory approach to conservation is emphasized.
Phenological and physiological evaluation of the potential of Tohono O'odham Z16 maize as a new crop for the semi-arid areas of SE-Kenya
(Journal of Agriculture in the Tropics and Subtropics, 1997) Shisanya, C.A.; Hornetz, B.
This study intends to compare the phenology, crop water requirements and the diurnal behaviour of leaf water potential of the new maize variety Tohono O'odham Z16 and of the locally grown varieties, i.e. Makueni DLC and Katumani Comp. B. under different watering treatments. The major objective of this study was to evaluate the potential of the new maize variety in a semi-arid environment of SE-Kenya, with a view to making recommendations on its suitability for incorporation into the maize breeding programme at NDFRC, Katumani, Kenya. The results ot this study showed that: a) Under optimum water requirements, Tohono Z16 attained full maturity within 70 days compared to 95 and 110 days for Makueni DLC and Katumani Comp. B, respectively. b) Makueni DLC and Katumani Comp. B maize varieties required about 41 % and 52% more water than Tohono Z16. c) Under rainfed treatment, leaf enrolling was more pronounced among the Tohono Z16 maize plants as compared to the other two maize varieties. This has been shown to be evidence for plant adaptation to water stress and results in a marked reduction in effective leaf area thus reducing the radiation load. d) Under rainfed treatment, Tohono Z16 maize attained a minimum LWP of about -2.38 MPa compared to -2.85/-3.00 MPa attained by Makueni DLC and Katumani Comp. B, respectively. The susceptibility of these latter two maize varieties to water stress is documented by the fact that they quickly leave their hydrature level early in the morning compared to Tohono Z16 maize which tends to maintain its level for a relatively longer period of time. As a result of this study, it is strongly recommended that Tohono Z16 be incorporated into the maize breeding programme at NDFRC, Katumani. It has been shown that Tohono Z16 maize possesses physiological characteristics which could be positively exploited by plant breeders at NDFRC, Katumani, in the search for drought adapted maize cultivars for the semi-arid areas of SE-Kenya.
Phenology and Diurnal Course of Leaf Water Potential of Three Bean Varieties under a Semi-Arid Environment in South-East Kenya
(Faculty of Science Kenyatta University, 1998) Shisanya, C.A.
The objectives of this study were to observe the phenology and to investigate the diurnal behaviour of leaf water potential (LWP) in three bean varieties under irrigated and unirrigated treatments with a view to making recommendations on their suitability for the semi-arid environments of Kenya. The field experiments were conducted during the short rainy season of 1993/94 in a typical semi-arid environment at KARIlNRRCIICRISAT Kiboko experimental field station, southeast Kenya. The selected beans were: high-yielding kenyan bean varieties Mwezi moja (MM) and Rose coco (RC) (Phaseolus vulgaris, var. GLP-I004 and var. GLP-2, respectively) and "minor pulse" Tepary beans (TB) tPhaseolus acutifolius A. Gray var, latifolius), possessing a high nutritional value. Under irrigated conditions, the bean varieties took 60 (TB), 65 (MM) and 70 days (RC), after emergence to reach full maturity respectively; water deficit induced false starting of phonological phases of the less adapted Phaseolus vulgaris. Differences in leaf water potential between the treatments were apparent. TB appeared to maintain higher leaf water potential values and showed more pronounced diurnal responses than MM and RC beans in both treatments. This also resulted in less yield reductions during water deficit for Phaseolus acutifolius. The susceptibility of Phaseolus vulgaris to water deficit is also documented by the fact that their LWP decreases more rapidly much earlier in the morning than TB. The short growth cycle of TB together with the maintenance of high leaf water potentials (and good yield performance) even under water deficit could be interpreted to mean that they are more adaptable to the semi-arid environments of Kenya compared to MM and RC beans.
Variations of the effective temperature index (ET) in Kenya
(GeoJournal, 1998) Makokha, G. L.
Using the Effective Temperature Index (ET) as a measure of climatic comfort conditions in Kenya, this study analyses its spatial, seasonal and diurnal variations. This index is computed using data collected from 57 weather stations spread throughout the country. Isarithmic mapping technique and the conditioning square method are used in this analysis. The results indicate that there exists in Kenya marked spatial, seasonal and diurnal variations of climatic comfort conditions. A classification of the country using this index and the Terjung (1968) system of climatic classification yields six climatic comfort zones. This type of physio-climatic studies has significant implications for Kenya in aspects such as building, clothing, recreation and sporting.
An investigation of the influence of human disturbance on selected soil nutrients in Narok District, Kenya
(Kluwer Academic Publishers, 1999) Ogutu, Z. A.
Selected soil nutrients were analysed purposely to establish whether they display a spatial pattern due to environmental factors and whether the pattern has been affected by human activities. Data analysis involved descriptive and canonical variate analysis. Except for grassland and shrubland sites, mean carbon, nitrogen, phosphorus, most base cations and copper in the 0–10 cm depth is low for disturbed sites. Within profile data are closer to each other than to data between profiles, suggesting that the former are chemically similar, and that the combined effects of underlying factors is similar. A two-dimensional ordination using canonical discriminant analysis suggests three soil sample clusters that are largely determined by altitude and moisture gradient. Sample ordination of group means show differences between disturbed and undisturbed forest and grassland site categories, suggesting the overriding role of human disturbance over environmental factors on soil nutrients.
Biological Nitrogen Fixation in Selected Legumes of the Semi-Arid Makueni District of Southeast Kenya
(Journal of Agriculture in the Tropics and Subtropics, 1999-10) Shisanya, C.A.; Maingi, J.M.; Gitonga, Nkanata Mburugu; Hornetz, B.
The major objective of this study was to investigate biological nitrogen fixation in two main legumes (green gram and common bean) grown in semi-arid southeast Kenya. Nodulation experiments on the two legumes were carried out in the greenhouse of the Botany Department, Kenyatta University with soil samples that had been obtained from Kiboko. Indigenous rhizobia were isolated from the two legumes and screened for the ability to fix nitrogen in comparison with commercially available strains from MIRCEN, UniverSity of Nairobi. The population of indigenous rhizobia specific to the two legumes was determined using the Most Probable Number (MPN) plant infection technique. Results showed that infectivity in common bean was better (80 nodules/plant) than in green gram (18 nodules/plant). Bisection of the nodules showed that 32 % and 77 % of them had an inner pink colour in common bean and green gram, respectively. This is an indication that a majority of the nodules in green gram were effective nitrogen fixers compared to those in common bean. The results of the MPN counts indicated that the number of indigenous rhizobia resident in Kiboko soils, and specific to green gram and common bean were 519-3,780 and 2,037-14,850 rhizobia cells per gram of soil, respectively. Two different isolates of rhizobia for common Bean (C_1S and C_2L) and one for green gram (GG-T), were isolated. Presumptive and authentication tests confirmed these isolates as rhizobia. Greenhouse trials showed thaI isolate C_1S and C_2L was not as effective in nitrogen fixation, as C_2L, and Rhizobium leguminosarum bv. phaseoli strain 446 from MIRCEN although no significant difference in Shoot dry weight was recorded for C_2L and 446. Further, isolate GG-T from green gram was not as effective in nitrogen fixation as the commercial strain Bradyrhizobium sp. strain CB1015.
Twenty Years of Resolving the Irresolvable: Approaches to the Fuelwood Problem in Kenya
(Wiley Online Library, 2001) Mahiri, I.; Howorth, C.
Resolving the fuelwood problem in Kenya has been the cause of many debates. A review of the literature reveals the changing emphasis on the cause and effect of the problem. The dominant focus links fuelwood consumption with environmental degradation. This view has been perpetuated and reinforced by the ‘Woodfuel Gap’ theory of supply and demand differentials, based on population growth. The demand mitigation has been addressed through the ‘Fuelwood Orthodoxy’ approach and energy technologies. This paper shows that deforestation, and subsequent degradation, has little to do with fuelwood consumption as much is extracted from outside the forest. Therefore, costly interventions of afforestation programmes have had little impact in addressing the issue. The locale-specificity of the fuelwood problem means there can be no simple, technical solution. The local nature of shortages means that national projections cannot capture the complex socio-economic and cultural issues. Such complexity and diversity of rural contexts demand that the rural energy problem cannot be treated in isolation from the equally pressing issues of poverty, labour, food, culture and values. Copyright © 2001 John Wiley & Sons, Ltd.
Crop water relationships and thermal adaptation of kathika beans (Phaseolus vulgaris L.) and green grams (Vigna radiata L. Wilczek) with special reference to temporal patterns of potential growth in the drylands of SE Kenya
(Journal of Arid Environments, 2001) Shisanya, C.A.; Hornetz, B.; Gitonga, Nkanata Mburugu
High soil temperatures influence seedling emergence as well as the performance of plant organs and yields. Temperatures of above 40°C were recorded in the topsoil of the Ferralsols of the semi-arid areas of SE Kenya during the rainy season. Experiments were conducted in the climatological laboratory of the University of Trier, Germany, on two legumes (green grams and common beans var. kathika), grown by smallholder farmers in the study area under varying soil temperature conditions. The main objective was to examine the effect of soil temperature on various parameters: seedling emergence, crop water requirements, leaf area index and phenology of the two legumes. The simulated climatological laboratory conditions were similar to those at Kiboko, SE Kenya. This study confirmed that under high soil temperature conditions, green grams are well adapted to semi-arid and hot tropical lowlands as well as lower midlands due to low water requirements, high seedling emergence rates and good yield performance. However, kathika beans were very susceptible to the simulated extreme climatic environment. By means of crop simulation modelling, a temporal differentiation for potential growth of green grams is presented for the long and short rains according to different rainfall conditions (ENSO, antiENSO, normal) over a period of 31 years.
Improvement of drought adapted tepary bean (Phaseolus acutifolius a. Gray var. latifolius) yield through biological nitrogen fixation in semi-arid SE-Kenya
(European Journal of Agronomy, 2002-01) Shisanya, C.A.
Tepary bean (TB), a drought adapted bean variety has recently assumed prominence among resource poor farmers in semi-arid SE-Kenya. However, its productivity is still low because of inadequate inputs. Greenhouse experiments were initially carried out to determine the number of rhizobia specific to TB in the soils of SE-Kenya, nodulation and nitrogen fixation of the same. The most probable number (MPN) of Rhizobia cells capable of nodulating TB were 1.0 × 102 cells per gram of soil in SE-Kenya. Subsequent field experiments were conducted at Kiboko KARI sub-station over two rainy seasons, i.e. long rains (LR) 1999 (March-June) and short rains (SR) 1999/2000 (October-January). The main objective was to screen various Rhizobia strains effectivity in nitrogen fixation with TB. The field trials showed that from the five Rhizobium strains tested only R3254 significantly increased pod dry weight, seed dry weight and seed yield/ha. Top dressed fertilizer N had no significant impact on growth and seed formation of tepary bean. Total nitrogen (N) concentration in the plant tissues was significantly enhanced in the course of the vegetative growth in R3254 treatment. This is an indication that Rhizobium strain R3254 can be used in the improvement of TB production for the resource poor farmers of semi-arid SE-Kenya.
The impact of ecotourism on livelihood and natural resource management in Eselenkei, Amboseli Ecosystem, Kenya
(Wiley, 2002-06) Ogutu, Z. A.
This paper presents the impact of ecotourism† on livelihood and natural resource management in the periphery of Amboseli Biosphere Reserve in Kenya. Ecotourism initiatives that have been introduced by Porini Ecotourism, a private investor, are benefiting Eselenkei Group Ranch in terms of income, improved infrastructure, employment opportunities and exposure. Over US$5000 is received annually as land rent, gate fee and bed charges. Twenty-six Maasai men are employed for the upkeep of project facilities. The community's capacity to facilitate resource-related conflicts has improved following support from development institutions. An expanding livelihood base is reducing local vulnerability to disaster and people–wildlife conflicts. The numbers of resident wildlife species in the conservation area have increased due to regeneration of woody species and reduced frequency of livestock. Despite the achievements, ecotourism is threatened by cultivation. The latter is jeopardizing conservation efforts, as the area frequented by wildlife is being lost and people–wildlife conflicts intensified. Another dilemma is that the Eselenkei community is not effectively participating in ecotourism a situation that is associated with inadequate management and negotiation skills in the group ranch committee. The latter requires leadership and microenterprise management skills if earnings from ecotourism are to be effectively invested in alternative sources of livelihood, to reduce current and potential conflicts. There is also need to build the community's capacity for the promotion of activities that compliment ecotourism. Frequent breakdown of community boreholes lead to dependence on the conservation area for water during prolonged drought, intensifying conflicts between livestock and wildlife.

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