Participatory soil and water conservation planning using an erosion mapping tool in the central highlands of Kenya

Despite several approaches that aimed at mobilising East African farmers to embrace soil and water conservation (SWC) activities, farmers hardly responded since they were seldom involved in the planning of SWC activities. Two tools that employ farmers' participation were developed and applied at Gikuuri catchment in Kenya. The first tool involved farmers to map soil erosion using their own indicators and determine the soil erosion status at catchment scale. This formed the basis upon which they undertook to plan for SWC measures at catchment scale. Farmers also predicted crop yield losses based on the soil erosion status. Farmers widely approved the soil erosion status map since their own indicators and perceptions were used. The second tool provided cash flow trends for a variety of SWC activities and farmer situations. Farmers can use land with a high, moderate or low erosion status and often have rather different socio‐economic settings. The net benefits over 5 yr for bench terraces, fanya juu terraces and grass strips were illustrated to assist farmers in making informed decisions on SWC adoption. The two tools increased awareness on the need for collective actions among farmers and showed fields that cause run‐on on downslope fields. The improved awareness of erosion problems and the related financial consequences increased farmers' willingness to share the investment costs for cut‐off drains. Copyright © 2007 John Wiley & Sons, Ltd.     

Farmers' perceptions of soil erosion and its consequences in India's semiarid tropics

This paper investigates farmers' perceptions of soil erosion and how it affects crop yields, land values, and private conservation investments in India's semiarid tropics. It is based on three types of data: (1) a survey of farmers in three study villages; (2) a plot survey by a professional soil surveyor in the same villages; and (3) experimental and simulated data from nearby research stations with similar conditions. Farmers' perceptions of erosion are compared to the surveyor's using kappa, a statistical measure of interrater agreement. Perceived erosion–yield relationships are estimated econometrically and compared to experimental and simulated data. Effects on land values and conservation investments are estimated econometrically. Findings suggest that farmers are keenly aware of rill erosion but less aware of sheet erosion; kappa values ranging from 0 to 0·28 suggest low agreement with the soil surveyor. They anticipate annual yield losses of 5·8–11 per cent due to rill erosion; these figures are reasonably consistent with those from nearby research stations. They anticipate yield increases of 3·8–14·5 per cent due to installation of soil conservation bunds, largely because they can harvest soil from up the slope and capture organic matter. Perceived erosion has some effect on land values and soil conservation investments, but other factors such as irrigation and soil type have a much greater effect. These findings suggest that promoting soil conservation requires capitalizing on farmers' interest in short‐term gains, such as from water and nutrient management. Copyright © 2005 John Wiley & Sons, Ltd.     

Farmers' knowledge of wind erosion processes and control methods in Niger

Field research on wind erosion processes in Sahelian Africa has revealed that wind-blown particle transport forms a constraint for local crop production systems. This paper describes the results of an on-farm survey on wind-erosion processes and soil conservation practices. Interviews were held with 138 farmers from seven villages in southern Niger. Of the interviewed farmers, 63 per cent consider wind-blown particle transport as damaging to their cropping systems. Nearly all farmers reported to observe differences between fields with respect to wind erosion. Fields that are mainly eroded were said to lose fertility and produce less, whereas deposition of material results in a better fertility and production. These differences occur also on a smaller scale, with erosion and deposition spots in the same field. Most farmers (96 per cent) are familiar with techniques to reduce wind erosion, and 92 per cent applied one or more of these techniques in the field. The indigenous soil conservation techniques are application of manure and mulching with crop residues or tree branches. New techniques are tree planting, natural regeneration of woody vegetation, and application of zai , a method of soil preparation from Burkina Faso, using pits filled with compost for sowing crops. The farmers who have applied these new techniques reported to have less wind-erosion problems in their fields. © 1998 John Wiley & Sons, Ltd.     

Mitigating soil erosion through farm-level adoption of soil and water conservation measures in Samanalawewa Watershed,Sri Lanka

Abstract

Soil erosion by water is currently one of the most notable types of land degradation in Samanalawewa Watershed in Sri Lanka, creating copious environmental and socioeconomic impacts. Thus, with the aim of detecting and mapping the rates of human-induced soil erosion in the watershed, remote sensing and geographic information system based modelling and field experiments were carried out. The results of the assessment disclosed that the present rate of human-induced soil erosion varies from 0 to 289 t ha^?1 yr^?1 with the majority of the area exceeding the natural rate of soil erosion by 14 to 33 times at present. However, the average rate of human-induced soil erosion has declined dramatically from 19.8 to 4.3 t ha^?1 yr^?1 from 1986 to 2008. In order to analyse the significant determinants of farm-level adoption of soil and water conservation measures, binary logistic regression procedure was applied using the data collected through a household survey (n = 201). The most significant (p<0.01) variables of the study were the farmers’ perceptions of soil erosion problems, gender of the household head, training on soil and water conservation, and ascertained advice from agricultural extension officers while the variables regarding past awareness about soil conservation technologies and off-farm income were significant at p<0.05. Furthermore, the study revealed that the majority (60.2%) of the farmers in the study area had been adopting different types of soil and water conservation measures for a prolonged period of time. Therefore, owing to the current decreasing rate of soil erosion, the soil and water conservation costs and the ratios of human-induced soil erosion vs natural soil erosion had declined significantly while the productivity of their lands had gone up.     

Farmers' perception of land‐cover changes in NE Iceland

Land degradation is considered to be a major environmental problem by scientific and political institutions in Iceland. In past years, land degradation problems related to sheep and horse grazing have gradually come to the fore in public discussion of environmental questions. However, land degradation is often evaluated in different ways by different groups of people. This has led to a lack of consensus regarding rates and severity of land degradation. Therefore, it is important to study differences in environmental perception, and how these differences can be dealt with in the context of sustainable management. This paper aims to highlight farmers' perception of land degradation in Iceland, as perceptions of the environment determine the basis for human activities related to the land. A total of 100 farmers in NE Iceland were questioned and interviewed for their opinions on land degradation, its history, causes and severity. The results indicate that farmers consider land degradation to be a slow process, and not a catastrophic phenomenon. The understanding of the general ecological processes by the users affects their practices and concern for their environment. This feeds back on the land‐use system and ultimately causes changes in land‐cover. Therefore, if we are to increase our understanding of the processes that lead to land‐cover changes we have to integrate the perceptions of land users and technical experts. In this way we may improve conservation practices and land‐resource management policies. Copyright © 2000 John Wiley & Sons, Ltd.     

A pragmatic approach to modelling soil and water conservation measures with a catchment scale erosion model

To reduce soil erosion, soil and water conservation (SWC) methods are often used. However, no method exists to model beforehand how implementing such measures will affect erosion at catchment scale. A method was developed to simulate the effects of SWC measures with catchment scale erosion models. The method was implemented by applying the LISEM model to an agricultural catchment on the slopes of Mt. Kenya. The method consisted of a field scale calibration based on P-factors, followed by application at catchment scale. This calibration included factors such as saturated conductivity, Manning's n, roughness and slope angle. It was found that using data on P-factors, such models can be calibrated to give acceptable predictions at pixel scale. However, P-factors were also found to vary with land use type and storm size. Besides, more data on the physical effectiveness of SWC measures are needed. At catchment scale, the effect of SWC was found to be different from that at pixel scale. Most SWC were simulated to be more effective at catchment scale, indicating additional infiltration during transport through the catchment to the outlet. However, slope corrections in case of terraces were found to be less effective at this scale. Nevertheless, a simulation for current land use with current SWC measures indicated that these SWC measures decrease runoff by 28% and erosion by 60%.     

Scientific evaluation of smallholder land use knowledge in Central Kenya

The following study was conducted to determine smallholders' land use management practices and agricultural indicators of soil quality within farmers' fields in Chuka and Gachoka divisions in Kenya's Central Highlands. Data on cropping practices and soil indicators were collected from farmers through face‐to‐face interviews and field examinations. Farmers characterised their fields into high and low fertility plots, after which soils were geo‐referenced and sampled at surface depth (0–20 cm) for subsequent physical and chemical analyses. Farmers' indicators for distinguishing productive and non‐productive fields included crop yield, crop performance and weed species. Soils that were characterised as fertile, had significantly higher chemical characteristics than the fields that were of poor quality. Fertile soils had significantly higher pH, total organic carbon, exchangeable cations and available nitrogen. Factor analysis identified four main factors that explained 76 per cent of the total variance in soil quality. The factors were connected with farmers' soil assessment indicators and main soil processes that influenced soil quality in Central Kenya. Soil fertility and crop management practices that were investigated indicated that farmers understood and consequently utilised spatial heterogeneity and temporal variability in soil quality status within their farms to maintain and enhance agricultural productivity. Copyright © 2007 John Wiley & Sons, Ltd.     

Farmers' perceptions of the role of scattered vegetation in wind erosion control on arable land in Burkina Faso

This paper describes the results of a survey on farmers' perceptions of the effect of woody natural vegetation on wind erosion. Sixty farmers were interviewed in three villages in northern Burkina Faso. The farmers mentioned that the presence of woody vegetation between the crops could benefit yield, but feared competition between the natural vegetation and the crop. Vegetation in a field was considered to increase deposition and decrease erosion on that field. The most important vegetative characteristics that affect wind erosion were, according to the farmers, vegetation's shape, porosity, flexibility and arrangement of the vegetation in the field. At present, most farmers do not apply this knowledge to the management of the natural woody vegetation on their fields. Copyright © 2005 John Wiley & Sons, Ltd.     

上海市水力侵蚀现状与水土保持措施分析

为研究上海市水土流失及措施现状,以第一次全国水利普查水土保持情况普查结果为基础,结合上海市基本情况,分析上海市水力侵蚀现状和水土保持措施情况。结果表明,上海市水土流失面积超过了200km^2,水土流失以河道两岸和湖泊沿岸的坍塌淤浅为主要特征,建设项目施工造成的人为水土流失也是上海市水土流失的一个重要方面。上海市中心城区水土保持措施较完善,但郊区部分河道还没有采取有效护坡措施,基本处于自然状态,很容易发生水土流失;因此,河道边坡和湖泊岸线的护岸整治、海岸滩涂的保滩促淤治理是上海市水土保持工作的重点,同时还应加强建设项目的监管和水土保持监测,以防止人为水土流失。     

Farmers' perceptions of soil erosion and soil fertility loss in Southern Ethiopia

Data and information about farmers' perceptions of soil degradation were collected using household survey, focus group discussion and field observations. The results indicate that farmers in the Sidama zone of southern Ethiopia are able to identify soil erosion and fertility loss indicators, take a holistic view of soil degradation and have a broad knowledge of the reasons for soil degradation. They perceive soil degradation mainly by reduced yields, soil changing in appearance and becoming stoney or coarse. The most frequently mentioned soil erosion indicator was soil becoming coarse and stony, followed by rill formation, dissection of fields and gullies and topsoil removal. The most important perceived indicator of soil fertility loss was reduced crop yield, followed by poor crop performance and yellowing of the crop. Farmers also have knowledge of solutions; however, participation in soil conservation activities is minimal because of the immediate threat of food insecurity. Any programme designed to address soil degradation in the region will have to be cognisant of farmers' knowledge and holistic view of soil degradation, and be integrated with aid measures to guarantee food security. Copyright © 2007 John Wiley & Sons, Ltd.     

延河流域水土保持措施减蚀效应分析

 利用延河流域35个雨量站50多年的日降雨、数字高程模型、土壤类型图、土地利用图和植被覆盖图、水土保持措施调查数据,结合黄土高原的区域特征,运用CSLE,在ArcGIS的支持下分别计算研究区1986、1997和2006年土壤侵蚀量,以1986年的水土保持措施实施情况作为基期水平,模拟1997、2006年在水土保持基期水平情景下的土壤侵蚀量,对比分析水土保持措施变化对土壤侵蚀量的影响。结果表明:以1986年作为基期,新增水土保持措施在1997年减少土壤侵蚀量96万t,在2006年减少土壤侵蚀量628万t;考虑2006年降雨特征不同于研究区多年降雨特征,按照2006年降雨特征计算,则新增水土保持措施在2006年减少土壤侵蚀量140万t。研究结果可为延河流域水土保持效益评价、水土流失治理和生态建设提供参考。     

自然侵蚀量和容许土壤流失量与水土流失治理标准

在总结分析国内有关自然侵蚀量、容许土壤流失量研究成果的基础上,探讨自然侵蚀量与容许土壤流失量的关系,讨论制订水土流失治理标准的思路。认为水土流失治理标准的确定有3个参考值：1）标准值,即一定条件下的容许土壤流失量,是水土流失治理至少要达到的目标,且随着对不同土地利用类型的功能需求与可实施的最佳水土保持措施、以及所在水土流失类型区的侵蚀危害与治理约束条件的不同而不同;2）理想值,即正常自然侵蚀状态下的土壤流失量;3）极端值,即土壤流失量为0,不发生水土流失。水土流失治理应是先控制到现时生态环境与社会经济条件下的容许土壤流失量范围内,逐步达到自然正常侵蚀量或制止水土流失的发生;还应引入环境伦理、环境美学及景观设计等理念,最终实现土地的可持续利用、区域生态系统的健康稳定及人与自然的和谐友好发展。     

Farmer perception of soil erosion and investment in soil conservation measures: emerging evidence from northern Taraba State,Nigeria

To combat soil erosion in the northern part of Taraba State, Nigeria, farmers are of major importance. Their perceptions vitally influence the levels of support and investment associated with solving problems of soil erosion through adoption of practices that are alternative to those in current use, including approaches focused on soil conservation. The objective of this study was to evaluate how farmer perceptions of soil erosion influence their investments in soil conservation, particularly soil or stone bunds, their applications of organic amendments and inorganic fertilizers and other soil conservation practices. In the study area, we undertook a field plot experiment and carried out a survey, using open‐ and closed‐ended questions. Water erosion and depletion of fertility were taken as the main indicators of soil erosion. The results of the experiment showed that farmers were aware of and perceived both indicators as having increased over the past decade. Farmer investments in water erosion control (3.7 US$/ha) and the prevention of soil fertility depletion (37.8 US$/ha) in the study area were found to be limited. The results also showed that awareness of water erosion was only marginally correlated with investment in water erosion control (χ² = 4.906, P = 0.09) and not associated with investments in soil fertility control measures (χ² = 0.175, P = 0.92). Those farmers who identified depletion of soil fertility as a problem, based on erosion, were not significantly more likely to make greater investments in soil conservation (χ² = 0.947, P = 0.62) but did invest more in fertility measures (χ² = 3.199, P = 0.20). Hence, further research is needed to determine other factors that may influence farmer investment in soil conservation, especially factors related to socio‐economic characteristics of farm households, institutional and technological innovations and field characteristics that were not addressed in this study.     

Farmers' participation in soil and water conservation activities in the Chemoga Watershed,Blue Nile basin,Ethiopia

Soil erosion by water constitutes a threat to the maintenance of the subsistence living of the Ethiopian rural population. Past efforts at Soil and Water Conservation (SWC) did not bring about significant results, mainly because of the top‐down approach pursued. Uprooting this past oversight and instating a participatory approach has since then been strongly recommended as the correct strategy. This paper analyses the extent of farmers' participation in current SWC activities in the Chemoga watershed, East Gojjam Zone, Amhara Regional State. Formal household survey, informal and focus group discussions and field observation were used to generate the data. The results indicate that the majority of the farmers participated in the SWC against their will. The most important factor discouraging them from participating freely was the perceived ineffectiveness of the structures under construction. Awareness about soil erosion as a problem, labour shortage and land tenure insecurity were found to be less important in providing an explanation for the disinterest shown by most of the farmers towards the SWC activities. Therefore, the important factors that need immediate consideration for SWC efforts in the study area or the region at large are: (1) SWC structures have to be carefully designed and constructed taking into account ground realities, and (2) participation of the farmers has to be through their own conviction regarding the effectiveness and efficiency of the technologies. Alternative SWC technologies will have to be considered in this regard. Copyright © 2002 John Wiley & Sons, Ltd.     

Modelling soil erosion and sediment yield at a catchment scale: the case of Masinga catchment,Kenya

Development of improved soil erosion and sediment yield prediction technology is required to provide catchment stakeholders with the tools they need to evaluate the impact of various management strategies on soil loss and sediment yield in order to plan for the optimal use of the land. In this paper, a newly developed approach is presented to predict the sources of sediment reaching the stream network within Masinga, a large‐scale rural catchment in Kenya. The study applies the revised universal soil loss equation (RUSLE) and a developed hillslope sediment delivery distributed (HSDD) model embedded in a geographical information system (GIS). The HSDD model estimates the sediment delivery ratio (SDR) on a cell‐by‐cell basis using the concept of runoff travel time as a function of catchment characteristics. The model performance was verified by comparing predicted and measured plot runoff and sediment yield. The results show a fairly good relationship between predicted and measured sediment yield (R²=0·82). The predicted results show that the developed modelling approach can be used as a major tool to estimate spatial soil erosion and sediment yield at a catchment scale. Copyright © 2006 John Wiley & Sons, Ltd.     

The influence of land management on soil erosion in the Sneeuberg Mountains,Central Karoo,South Africa

Farm practices in the Sneeuberg Mountains, Karoo, South Africa are examined to assess their contribution to the development of the observed gullies and badlands. Data from the literature is augmented by interviews with local farmers and measurements in the field. Changes in stocking rates, grazing systems and technological advances are assessed for their impact on soil erosion, vegetation cover and species composition. The possibility of natural and managed rehabilitation of badland areas is discussed, as are future prospects for farm management in the Sneeuberg. The findings suggest that high stock numbers and less benign management practices in the 19th century and the early 20th century underlie much of the degradation seen today. Copyright © 2007 John Wiley & Sons, Ltd.     

Erosion modelling approach to simulate the effect of land management options on soil loss by considering catenary soil development and farmers perception

The prevention of soil erosion is one of the most essential requirements for sustainable agriculture in developing countries. In recent years it is widely recognized that more site‐specific approaches are needed to assess variations in erosion susceptibility in order to select the most suitable land management methods for individual hillslope sections. This study quantifies the influence of different land management methods on soil erosion by modelling soil loss for individual soil‐landscape units on a hillslope in Southern Uganda. The research combines a soil erosion modelling approach using the physically based Water Erosion Prediction Project (WEPP)‐model with catenary soil development along hillslopes. Additionally, farmers' perceptions of soil erosion and sedimentation are considered in a hillslope mapping approach. The detailed soil survey confirmed a well‐developed catenary soil sequence along the hillslope and the participatory hillslope mapping exercise proved that farmers can distinguish natural soil property changes using their local knowledge. WEPP‐model simulations show that differences in soil properties, related to the topography along the hillslope, have a significant impact on total soil loss. Shoulder and backslope positions with steeper slope gradients were most sensitive to changes in land management. Furthermore, soil conservation techniques such as residue management and contouring could reduce soil erosion by up to 70 percent on erosion‐sensitive slope sections compared to that under tillage practices presently used at the study site. The calibrated model may be used as a tool to provide quantitative information to farmers regarding more site‐specific land management options. Copyright © 2008 John Wiley & Sons, Ltd.