ABSTRACT
Increased human population pressure and climate change constitute the global underlying root causes of accelerated and devastating land degradation processes in the Arid and Semi-Arid Lands (ASALs). River Loboi watershed, located at the lower part of the Lake Baringo Catchment, is not an exception. The area is characterized by severe soil degradation that has resulted in excessive vegetation deterioration. This study set to assess the land degradation menace in the river Loboi watershed with specific objectives of determining the vegetation cover and composition, investigating the physiochemical condition of the soil as well as assessing the socio-economic status of the inhabitants. The study undertook a socio-ecological cross-sectional survey of some selected biophysical and socio-economic indicators of land degradation. Tools for data collection included structured questionnaire, observation schedules, laboratory analysis and oral histories. The measured variables were analysed using frequencies, crosstabulations, one-way ANOVA and correlation analysis. Except for correlation analysis, all the analyses were done at α =0.05 level of significance. The results indicated that the whole watershed is has undergone both soil and vegetation degradation. The locals are not able to curb this problem primarily due to lack of appropriate knowledge and financial constrains. The vegetation cover is 59.6% and the watershed has transformed from the typical ‘savannah’ onto a shrubland. This vegetation change has negatively impacted on the soil condition and as a result signs of massive gully erosion are enormous. In addition, the soils are of low fertility. In general, 87.5% of the watershed is highly degraded with the remaining 12.5% moderately degraded. The middle section (Simotwe location) is the most affected part (‘hotspot’) in the watershed. It recorded the least soil organic matter level of 1.3% and least vegetation cover of 51.4%. These results demonstrate the urgency of developing and establishing more effective and scientific ways to curb and monitor land degradation processes in the watershed.
CHAPTER ONE
INTRODUCTION
Background of study
The Arid and Semi-Arid Lands (ASALs) are characterised by harsh climatic conditions and are ecologically sensitive environments (Akuja et al., 2005 and Njoka et al., 2005). In Africa they are characterised by unpredictable rainfall and long periods of drought; limited water resource and inadequate knowledge and technology of water resource management. These regions are experiencing rapid population growth coupled with low or declining real incomes and low nutritional levels; serious environmental degradation and the externalities of modernization and economic development (Darkoh, 1996).
In Kenya, Arid and Semi-Arid land covers 80% of the country (Sutherland et al., 1990). The current rapid increase in population and the associated demand for land in the high potential areas, has led to migration of people to the ASALs (Johansson and Svensson, 2002 and Njoka et al., 2005). This has resulted in severe land degradation (Johansson and Svensson, 2002 and Akuja et al., 2005). According to Williams and Balling (1996) land degradation is the reduction of biological productivity of ASAL ecosystems, including rangeland pastures and rainfed and irrigated croplands, as a result of acceleration of certain natural, physical, chemical and hydrological processes. These processes may include erosion and deposition (by wind and water), salt accumulation in soils, ground water or surface run-off, a reduction in the amount of natural vegetation and a decline in the ability of soils to transmit and store water for plant growth. It basically involves deterioration in soil, water and vegetation resources (Chuchu, 2008).
The River Loboi watershed is undergoing land degradation through accelerated soil erosion and vegetation loss. The main causes of land degradation in the watershed are overgrazing, poor watershed management, poor farming practices and indiscriminate cutting of trees for fuel (GoK, 2002). The degradation has resulted in off-site effects like sediment accumulation in Lake Bogoria and Kiborgoch swamp. For instance, the Kiborgoch swamp, formerly known as the greater Loboi swamp, is said to be more than twice the present size and free from trees a few years ago. In addition, it has transformed from an expanse of tall cattail, Typha domingesis to a complex mosaic riddled with different species of Acacia trees. The consequences of such changes include loss of organic matter, erosion, loss of biodiversity and habitat changes for many plant and animal species.
Land degradation particularly soil deterioration and vegetation cover loss negatively impact on the watershed hydrology dynamics (ICRISAT, 1989 and Rose, 1990). It exposes the soils to agents of erosion and during rainfall, there is increased surface runoff (FAO, 1986; Gachene, 1995 and Johansson and Svensson, 2002). Consequently, underground water balance changes as a result of reduced rainwater infiltration (Jones, 1997 and Rose, 1990). These leads to shortage of water supply as springs and rivers have their duration of flow reduced drastically (FAO, 1986).
The effects of land degradation are immense and with the fact that the ASALs are now the only areas still available for agricultural expansion, there is need for improved management of the ASALs (Johansson and Svenssson, 2002 and Njoka et al., 2005). For instance, integrating watershed management concept onto soil and water conservation meseasures will results in increased annual yield of usable water for downstream users and reduced run-off volumes and peak discharges for moderating floods hence promoting environmental conservation (FAO, 1986 and ICRIAST, 1989).
A clear understanding of the status of biophysical degradation and the socio-economic condition of the locals is important for sound intervention in mitigating land degradation. The purpose of this research study was to assess the ground surface characteristics (especially the vegetation and soil resources) as well as the socio-economic factors so as to be able to establish the nature of the problem of land degradation in the watershed. The findings of the study will now be used as the basis of planning and designing of effective control, rehabilitation and preventive measures to combat the land degradation problem in the watershed. The common degradation effects in the area especially siltation and flooding experienced downstream will then be minimised. The findings can also be used to identify the areas most affected by land degradation (‘hotspots’) as well as provide a basis for monitoring the progress of rehabilitation efforts.
Statement of the Problem
As is the case in most parts of Africa, land degradation assessments in the Baringo County have basically embarked on the estimation of the rate of soil erosion (Johansson and Svensson, 2002 and Warren, 2002). Onyando et al., 2005, estimated the potential soil erosion from River Pekerra catchment using the Universal Soil Loss Equation (USLE). Using a socio-economic approach, Johansson and Svensson, (2002) did a pilot study on the physical causes of land degradation in the semi-arid catchments of Lake Baringo. Chebet, (2002) also carried out a socio-economic survey on the utilization of lake Bogoria wetland ecosystem. These constitute some of the many studies whose interest revolve around the conservation of Lake Baringo and Lake Bogoria. Most of these studies are socio-economic in nature and/or lack a scientific integrated approach. In addition the spatial scale of some of the assessments is too large to effectively capture the local phenomena. Based on this, failure of past rehabilitation and restoration programmes in the area can be attributed to lack of consistent, site specific baseline information on land degradation which constrains effective designing of control measures; the identification of priority areas and monitoring of the consequences of rehabilitation actions (Campell et al., 2003 and Adeel et al., 2005). As a result Baringo County remains to be one of the highly degraded regions in Kenya. This continued land degradation has resulted to severe loss of arable land for rainfed crop production and extreme forage shortage for livestock production hence exacerbating food insecurity in the County. River Loboi watershed is one of the most affected areas in the County.
Objectives
General Objective
This study was to generate ground-based biophysical baseline information that can be used as a basis for making recommendations for sustainable land degradation control practices in the river Loboi watershed of Baringo County, Kenya.
Specific Objectives
i. To assess the socio-economic condition (especially aspects on education, access to social amenities and income level) of the inhabitants of river Loboi watershed.
ii. To assess the vegetation resource deterioration (cover, species composition and alterations) in the river Loboi watershed.
iii. To assess selected soil physiochemical characteristics (visible erosion, macro elements, organic matter and pH) in the river Loboi watershed.
Research Questions
i. What is the educational level and occupation of household heads; housing and sanitation facilities; average number of livestock and acreage holding per household in the river Loboi watershed?
ii. What is the vegetation cover, dominant type/plant species in the river Loboi watershed?
iii. What is the level of soil pH, organic matter and major macro-elements and which is most prominent erosion type (by water) in the river Loboi watershed?
Justification
With increasing human population and limited arable land, the ASALs remain the only areas still available for agricultural expansion (Johansson and Svenssson, 2002 and Njoka et al., 2005). Therefore, the problem of land degradation in the ASALs requires urgent consideration. In spite of some studies and many projects that have been funded for purposes of combating land degradation in the Baringo County, it remains to be one of the highly degraded regions in Kenya. In attempting to curb land degradation, understanding its current status of is very important (Taddese, 2001 and Charbrillant et al., 2002). Information on the current situation of land degradation problem assists in the designing and planning of appropriate control measures as well as identifying priority areas for intervention. This study was therefore intended to generate such information. The study findings can be used by policy makers, the community in the watershed, individual farmers, researchers and extension staff to enhance adoption of appropriate land degradation control measures in the river Loboi watershed and other similar conditions in the county. It will also ensure that rehabilitation efforts are well focused. Successful amelioration of the situation will reduce the soil erosion menace in the watershed and increase land potentiality and this will translate to increased agricultural productivity as stipulated in vision 2030. This will also enhance the achievement of two Millennium Development Goals: extreme poverty and hunger eradication (no. 1) and that of environmental sustainability (no.7).
Scope of Study
This research study was carried out in the River Loboi watershed that stretches from Kibomui village in Kapkechui location down to Kiborgoch swamp in Koibos Location. The study assessed the nature and extent of land degradation in the seasonal stretch of the watershed, using selected biophysical indicators. Parameters for physical degradation were soil organic matter content, nutrient levels, soil pH and the visible erosion type. Vegetation cover and alteration of key/dominant plant species constituted the indicators for biological degradation. Being a ground- based assessment, the study involved field measurements and laboratory analysis of the mentioned indicators. This biophysical assessment was then complemented by a household socio-economic survey on the inhabitants within the watershed.
Limitations of Study
The line-intercept method of measuring vegetation (cover and composition) records only a small amount of vegetation along each line. For desired precision, it is required that a relatively large number of transects ought to be established in the study area. Only eight transects were located in the watershed. To minimize this limitation, the step-point method was used together with the line-intercept method. In general, the change from the initial Y-sampling technique for data collection to the line transects technique was be attributed to the financial constraints experienced during the study.
A reliable estimate of household income was difficult to obtain within the watershed due to principally to unwillingness of household heads to divulge all sources and levels of income. To overcome this limitation, housing type, level of education and livestock numbers and rearing system were used as a proxy to household socio-economic status.
Definition of Terms
Arid and Semi-Arid Lands (ASALs)/dryland: refers to the terrestrial regions where water scarcity limits the production of crops, forage, wood and other ecosystem provisioning services. Assessment: refers to evaluation of a situation, event, phenomena or condition.
Cover: this is the proportion of the ground obscured by a species’s above ground leaves and stems (and flowers).
Household: comprises of a person or group of persons who are generally bound together by ties or kinship or joint financial decision who live together under a single roof or compound and are answerable to one person as the head.
Land: is the solid surface of the globe that usually supports biological production. Land Degradation: is lowering in quality or deteriorating in the condition of land. Land use: refers to mans’ activities on land.
Soil: is the loose material composed of weathered rock and other materials and also partly decayed organic matter that covers large part of land.
Watershed: refers to the whole water gathering ground of river system.
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Item Type: Kenyan Topic | Size: 87 pages | Chapters: 1-5
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