Soil erosion monitoring indicators: An approach towards natural resource management in Kuresoi South, Kenya

Soil erosion is still one of the most important land problems and it is linked to land use and land cover changes. Soil erosion has negative effects on land resource which ultimately affects agricultural productivity and water quality due to sedimentation. Local monitoring systems constitute an almost compulsory component of any program or project dealing with sustainable management of natural resources. The purpose of this study was to identify soil erosion monitoring indicators in Kuresoi South, Kenya. The study was comprised of a total representative sample population of 68 respondents from Kuresoi south catchment which was achieved using Nassiuma coefficient of variation formulae. Our findings reveal a positive significant relationship between soil erosion monitoring indicators and natural resource management. Taken together, soil erosion monitoring indicators can be used in detecting change over time in soil resource.


Introduction
Soil erosion is a major problem confronting land and water resources. The rate of erosion is primarily determined by the erosive events (e.g., short duration and highintensity rainfall events), soil type, and characteristics of the terrain (Wei et al., 2007). The impacts of accelerated soil erosion processes can be severe, not only through land degradation and fertility loss but through a conspicuous number of off-site effects such as sedimentation, siltation, and eutrophication of waterways or enhanced flooding (Borrelli et al., 2017).
Soil erosion rates are exacerbated for the arid and semi-arid regions due to barren mountains with scattered vegetation that provide direct exposure to heavy rainfall (Vijith et al., 2018). In Kenya, Soil erosion is one of the most important land problems and it is linked to land use and land cover changes. For instance, this problem has persisted in Kuresoi South where its negative effects on land resource, soil productivity, available agricultural land, and water resources due to sedimentation has been dominant.
To date, various studies have been conducted to determine the strategies employed in monitoring soil erosion (Shen et al., 2009;Wang et al., 2009;Wu & Chen, 2012;Xu, Xu, Wu, & Tang, 2012). Nonetheless, less focus has been directed to Kuresoi South ward yet it is an agriculturally productive area which is experiencing high population growth. In fact, farmers in this area continue to experience soil erosion despite effort to conserve soil. This threatens agronomic productivity, the environment, food security, quality, and the well-being of many small-scale farmers. Therefore, the present study seeks to answer the question on whether there any soil erosion Monitoring Strategies in Kuresoi. Providing an answer to this question will immensely help the land use planners, environmental planners, and policy makers to identify and execute site specific best management practices to bring soil erosion rates within the permissible limits at the local environment.

Study area
This study focuses on Kuresoi ward in Nakuru County, within a latitude of -0.3015° S and a longitude of 35.5307° E. Its elevation is 2551 meters feet. It is located next to the South West Mau Forest and is experiencing high population growth and people engage in wide range of agricultural activities such as farming, poultry and herd keeping for their livelihood. The area under study is under significant human pressure through encroachment to the remaining parts of the forest, charcoal burning, grazing, illegal tree logging, smallholder agriculture and subsistence farming. The area is therefore prone to soil erosion due to the many human activities taking place. It was therefore important to identify some soil erosion monitoring strategies to manage the problem of soil erosion.

Research Design
This study used descriptive research design to describe soil erosion monitoring strategies as indicators of soil erosion and natural resource degradation. This was deemed since it helped to provide answers on the questions of who, what, when, where Bryman & Cramer.,1997) and how associated with soil erosion monitoring strategies. Kothari (2004) defines target population as the total number of items that the study intends to investigate them. They are a well-defined set of people, a group of things, households, elements, services, and events that are being discussed. Therefore, the target population in this study was the small holder farmers of Kuresoi South constituency, Kuresoi ward with specific focus to three villages; Mwaragania, Kibugat and South B within the affected regions. The total population of this area is 6,649 (2019 Census) and is distributed in the table below.

Sample and Sampling Procedures
Sampling is the selection of subset of units, people, or items, from the target population. This is for the purpose of collecting information which is used to draw deductions about the entire population (Kothari, 2014). A sample is the subset of units that are selected and they are used to represent the entire population (Mugenda & Mugenda, 2003). According to Abraham and Rusell (2008), a sample size should be greater than 30 for inferential statistics to be conducted. In this study, the sample was 68 households and was obtained using Nassiuma Coefficient of variation formula (Nassiuma, 2000).

Data Collection Instruments
Primary data collection was used in the collection of data where open and closed ended questionnaires adopted as well as the use of camera for capturing picture. Open ended questions gave deeper information about the soil erosion monitoring strategies while closed ended provided quantitative analysis for the study.

Validity of the Research Instrument
This is the adequate reporting of the objectives under study and the measure of accuracy (Cohen et al, 2000). Instrument's validity is significant for logical premises and accuracy (Oso and Onen, 2008). The instruments were interrogated by the supervisors in the university together with the peers and the way forward was decided. The pretesting of the instruments enabled for the evaluation of the content's validity.

Reliability of the Research Instrument
A pilot study was conducted in order to ascertain the reliability of the research instruments, detect any ambiguities, identify the questions that are constructed poorly and cannot be understood together with those questions that are irrelevant. Mugenda and Mugenda (2003) recommended 10% of the sample size is appropriate for pilot study. A pilot of 7 respondents from the target population was selected randomly to test the questionnaires. Cronbach alpha with a set lower limit of Cronbach alpha 0.6 acceptability was used to analyze the results of the pilot test. The study found an overall Cronbach alpha results of 0.762 which is more than the recommended threshold of 0.6.

Data analysis
Data analysis is a technique that investigates what has been collected in the research and make conclusions (Kombo, 2004). It seeks to fulfill each research objective and provide answers to the research questions (Bryman & Cramer, 1997). Descriptive statistics were used to analyze the data in this study. This describes and explains what the data shows about soil erosion monitoring strategies. After data collection, the researcher edited, coded, and presented the results in the form of frequency tables, graphs and pie-charts for easier understanding and interpretation. Descriptive statistics such as mean was used to summarize the data. Regression model was also used to establish the relationship between soil erosion indicators and soil management.

Comment [GY6]
: I think that expalining a technique used in this study is enough rather than defining the meaning of data analayisi. Please, focus on the issue of your research.

Age of the respondents
The age of the respondents was established and the results provided in figure 2 below

Figure 2: Age of the respondents
The largest number came from age bracket of 20 -40 years with 24(41%), followed by 40 -60 years with 22(37%) then 60 and above with 9(15%) and finally 18 and below with 4(7%). It is evident that most of the respondents are youths in the society who are active and engage in economic activities like farming and animal rearing which are the major factors casing soil erosion.

Landscape characteristics
How the area was when the respondents first came was also assessed. It was provided in table1 below; The findings indicated that 39(66%) of the respondents indicated that the area was forested when they first came. 9(15%) indicated that it was an agricultural land while 6(10%) indicated that it was a bare land and 5(9%) indicated that it was a grassland.

Figure 3: How was the area when you first came
Most respondents (66%) indicated that the area was forested when they first came. This shows that soil erosion was not a serious environmental problem at that time. However, 15% responded that it was an agricultural land, to show that as time went by, there was massive migration of people to this land and the residents began to clear the forests in their land to create space for farming. Small channels greatly indicated the presence of rill erosion (mean of 3.4068 whereas deep channels indicated the occurrence of gully erosion (mean of 3.6102). The river water had been significantly decolorized and roots of plants exposed due to soil erosion (mean of 3.2203 and 4.2034 respectively). At the same significant rate, rocks located in the rivers had been exposed and sediments found along the drainages and river banks to indicate the presence of soil erosion (mean of 3.0169 and 4.2034 respectively). Change in soil color, tree mounds and pedestals indicated the presence of soil erosion at a low rate since they are observed after a long period of time (mean of 2.6271, 2.6102 and 2.0169 respectively).
Soil erosion monitoring indicators were therefore significant in assessing the effectiveness of natural resource management by a mean of 3.9492. Studies by Ypsilantis (2011) support these studies. He proposes that soil erosion monitoring indicators are important in providing qualitative assessment of erosion so that the sites that indicate potential erosion problems be red flagged and mitigating measures can be implemented to correct the problem. Rills and gullies were presented at a highly significant rate to show that rill erosion and gully erosion had taken place in most places and the necessary mitigation measures had to be put in place. The river water have been decolorized due to soil erosion and thus not fit for human consumption 0(0.00%) 23(39.0%) 0(0.00%) 36(61.0%) 0(0.00%) 3.2203 .98380 The roots of plants and trees have been exposed due to soil erosion 0(0.00%) 0(0.00%) 0(0.00%) 47(79.7%) 12(20.3%) 4.2034 .40598 Rocks located in the fields and rivers have been exposed due to prolonged soil erosion 0(0.00%) 23(39.0%) 24(40.7%) 0(0.00%) 12(20.3%) 3.0169 1.10628 There are sediments on the drainages/river banks which shows that soil erosion has taken place 0(0.00%) 0(0.00%) 0(0.00%) 47(79.7%) 12(20.3%) 4.2034 .40598 The color of the soil in the farm has changed due to soil erosion 11(18.6%) 12(20.3%) 24(40.7%) 12(20.3%) 0(0.00%) 2.6271 1.01537 The soil under the trees in the field is at a higher level than the soil in the surrounding area which indicates prolonged soil erosion  The results of the findings above revealed that at the level of significance 0.05 soil erosion monitoring indicators identified by the community are significant in natural resource management (F = 27.684, P<0.05).

Discussion
The findings revealed that most respondents experienced decline in crop yield as result of soil erosion. The soil erosion has caused rills, gullies, tree root exposure, decolorisation of the river water, rock exposure and sedimentation as physical indicators of soil erosion in their farms and fields. Change in soil color, tree mounds and pedestals were experienced by few respondents. Therefore, in order to obtain high success rates in natural resource management, there is need to implement management techniques that will curb rill, gully, and sheet erosion since these types of erosion are responsible for decline in crop yield, decolorisation of the river water, sedimentation, tree/plant root exposure and rock exposure. Soil erosion monitoring indicators significantly affect natural resource management. It was also reflected in the regression model where soil erosion monitoring indicators was the second leading variable on predicting natural resource management

Conclusion
The study established that soil erosion monitoring indicators (rills, gullies, Tree root exposure, Rock exposure, Pedestal, and Decolorized River water) are important in natural resource management. These indicators are used in detecting change over time in soil resource. They help during natural resource decision making during environmental planning and management.